Dr Andrew Wilson

Movement control faces a problem of redundancy. In general, there are more degrees of freedom available to solve a task than the task requires. This ‘degrees of freedom’ problem has been reframed as a ‘motor abundance’ feature (Latash, 2012), where the redundancy enables crucial flexibility. The balance between flexibility and control has been proposed to depend on synergies, which are lower-dimensional organisations of movement dynamics into systems that solve the task at hand. There are now several movement analysis methods designed to search for the signatures of synergies (the uncontrolled manifold, Scholz & Schöner, 1999; tolerance-noise-covariation, Cohen & Sternad, 2009, and others) and a great deal of empirical evidence that synergies feature in movement control. However, while all of these analysis methods rely on notions of ‘task’ to constrain movement solutions, they do not come with a formal theory of what a task is or how tasks are perceived. This paper proposes the hypothesis that tasks should be formalised as task-dynamical affordances, and that perceiving these via specifying information is how they constrain synergy formation (effectivities). I lay out the hypothesis, and detail a research programme to investigate the hypothesis, with reference to existing work on throwing.

Roger Shepard's description of an abstract representational space defined by landmark objects and kinematic transformations between them fails to successfully capture the essence of the perceptual tasks he expects of it, such as object recognition. Ultimately, objects are recognized in the context of events. The dynamic nature of events is what determines the perceived kinematic behavior, and it is at the level of dynamics that events can be classified as types. [Shepard]

We recently found that older adults show reduced learning rates when learning a new pattern of coordinated rhythmic movement. The purpose of this study was to extend that finding by examining the performance of all ages across the lifespan from the 20 s through to the 80 s to determine how learning rates change with age. We tested whether adults could learn to produce a novel coordinated rhythmic movement (90° relative phase) in a visually guided unimanual task. We determined learning rates to quantify changes in learning with age and to determine at what ages the changes occur. We found, as before, that learning rates of participants in their 70 s and 80 s were half those of participants in their 20 s. We also found a gradual slow decline in learning rate with age until approximately age 50, when there was a sudden drop to a reduced learning rate for the 60 though 80 year olds. We discuss possible causes for the "50 s cliff" in perceptuo-motor learning rates and suggest that age related deficits in perception of complex motions may be the key to understanding this result.

A central question in motor control is whether that control is predictive or prospective. However, these terms are used widely and inconsistently throughout the literature, which makes it hard for research to reliably build or be challenged. Our goal is to clearly identify the ways in which these terms get used, and to identify what each approach commits to as a theory of motor control. We have identified three notions of predictive control (Perception-Action, Predictive Processing, and the Free Energy Principle) and two of prospective control (Perceptual Control Theory, and Ecological Psychology), and here we briefly discuss what each entails, with reference to key literature and examples. We hope that this guide will help researchers be clear about exactly which approach they are taking, and how they have engaged with the key elements of their chosen approach.

In two experiments, the current study explored how affordances structure throwing for long distance and accuracy. In Experiment 1, 10 expert throwers (from baseball, softball and cricket) threw regulation tennis balls to hit a vertically oriented 4x4ft target placed at each of 9 locations (3 distances x 3 heights). We measured their release parameters (angle, speed and height) and showed that they scaled their throws in response to changes in the target’s location. We then simulated the projectile motion of the ball and identified a continuous sub-space of release parameters that produce hits to each target location. Each sub-space describes the affordance of our target to be hit by a tennis ball moving in a projectile motion to the relevant location. The simulated affordance spaces showed how the release parameter combinations required for hits changed with changes in the target location. The experts tracked these changes in their performance and were successful in hitting the targets. We next tested unusual (horizontal) targets that generated correspondingly different affordance sub-spaces to determine whether the experts would track the affordance to generate successful hits. Do the experts perceive the affordance? They do. In Experiment 2, 5 cricketers threw to hit either vertically or horizontally oriented targets and successfully hit both, exhibiting release parameters located within the requisite affordance sub-spaces. We advocate a task dynamical approach to the study of affordances as properties of objects and events in the context of tasks as the future of research in this area.

Previously, we measured perceptuo-motor learning rates across the lifespan and found a sudden drop in learning rates between ages 50 and 60, called the "50s cliff." The task was a unimanual visual rhythmic coordination task in which participants used a joystick to oscillate one dot in a display in coordination with another dot oscillated by a computer. Participants learned to produce a coordination with a 90° relative phase relation between the dots. Learning rates for participants over 60 were half those of younger participants. Given existing evidence for visual motion perception deficits in people over 60 and the role of visual motion perception in the coordination task, it remained unclear whether the 50s cliff reflected onset of this deficit or a genuine decline in perceptuo-motor learning. The current work addressed this question. Two groups of 12 participants in each of four age ranges (20s, 50s, 60s, 70s) learned to perform a bimanual coordination of 90° relative phase. One group trained with only haptic information and the other group with both haptic and visual information about relative phase. Both groups were tested in both information conditions at baseline and post-test. If the 50s cliff was caused by an age dependent deficit in visual motion perception, then older participants in the visual group should have exhibited less learning than those in the haptic group, which should not exhibit the 50s cliff, and older participants in both groups should have performed less well when tested with visual information. Neither of these expectations was confirmed by the results, so we concluded that the 50s cliff reflects a genuine decline in perceptuo-motor learning with aging, not the onset of a deficit in visual motion perception.

Perception-action systems are redundant; they have more degrees of freedom available than are required to perform any given task. In order to do anything specific, these must be constrained into a task-appropriate organisation. Methods that analyse the variability of movements (e.g. the uncontrolled manifold, UCM) reveal that these organisations are synergies; specific organisations of DoF that constrain their variability to exhibit ‘repetition without repetition’; the same basic outcome, while the specific kinematics may vary from trial to trial. When the right synergy is operating, movement control is stable and adaptive. What is currently missing from this story is a mechanism that would actually allow an organism to select, assemble, and control the ‘right’ synergy; this is currently a researcher degree of freedom. This talk will lay out the hypothesis that the perception of affordances, and the process of affordance-based control, is that mechanism; affordances are the task goal that constrains synergy formation and variability (for organism and researcher both). To make this argument, I will review my recent work on the affordances for long-distance, targeted throwing, where I have formalised affordances in task-dynamical terms and showed how such affordances can be used to meaningfully constrain a UCM analysis of thrower kinematics.

The stability of coordinated rhythmic movement is primarily affected by the required mean relative phase. In general, symmetrical coordination is more stable than asymmetrical coordination; however, there are two ways to define relative phase and the associated symmetries. The first is in an egocentric frame of reference, with symmetry defined relative to the sagittal plane down the midline of the body. The second is in an allocentric frame of reference, with symmetry defined in terms of the relative direction of motion. Experiments designed to separate these constraints have shown that both egocentric and allocentric constraints contribute to overall coordination stability, with the former typically showing larger effects. However, separating these constraints has meant comparing movements made either in different planes of motion, or by limbs in different postures. In addition, allocentric information about the coordination is either in the form of the actual limb motion, or a transformed, Lissajous feedback display. These factors limit both the comparisons that can be made and the interpretations of these comparisons. The current study examined the effects of egocentric relative phase, allocentric relative phase, and allocentric feedback format on coordination stability in a single task. We found that while all three independently contributed to stability, the egocentric constraint dominated. This supports previous work. We examine the evidence underpinning theoretical explanations for the egocentric constraint, and describe how it may reflect the haptic perception of relative phase.

The stability of coordinated rhythmic movements is primarily affected by the target relative phase. Relative phase can be identified in each of two frames of reference (an external, allocentric frame and a body-centred, egocentric frame) and both constrain stability. In the allocentric frame, coordinations that involve isodirectional movement (0° mean relative phase) are more stable than those that do not. In the egocentric frame, coordinations that involve simultaneous use of homologous muscles (in-phase) are more stable than those that do not. The origin of the allocentric constraint is the visual perception of relative phase. The origin of this egocentric frame of reference is still unclear, although it is typically discussed in terms of neural crosstalk. Pickavance, Azmoodeh & Wilson (2018) proposed that the egocentric constraint is also perceptual, based in the haptic perception of relative phase. As an initial step in pursuing this hypothesis, this exploratory report examines some data from two recent studies on the effect of ageing on performing and learning coordinated rhythmic movements. We show that participants in their 20s show a strong egocentric effect in their coordination production, while this disappears in participants in their 60s. Participants in their 50s show an intermediate effect. We propose that a perceptual hypothesis is the best explanation of this age-related change, and lay out how to pursue hypothesis-driven tests in the future.

Ever since Gibson proposed the concept of affordances in 1979, ecological psychologists have been arguing about the best way to formalize the idea in a way that can allow us to successfully explain as much of behavior as possible. The first approach was to consider them as dispositional properties of task environments which can support skillful perception and action. These are perceived via lawfully created ecological information variables in ambient perceptual arrays (Turvey, Shaw, Reed & Mace, 1981). A more recent approach considers them more broadly as relations between properties of organisms and their environments. This expands the spatial and temporal scope of affordances; we stand in many kinds of relations to our physical but also social and cultural environments. Relational affordances are therefore offered as an ecological way to explain behaviors in these so-called ‘representation-hungry’ domains (Chemero, 2009; Rietveld & Kiverstein, 2014). These are perceived via general ecological information (Bruineberg, Chemero & Rietveld, 2018) which allows a wider class of environmental regularities to be informative about the relation. This paper will argue that general ecological information is not actually perceptual information; it does not come into suitable contact with an organism and thus cannot support the perception of anything, let alone the relational affordances that depend on it to be psychologically relevant. I will show that the affordances-as-relations ontology cannot be an ecological solution for explaining a behavior, and point to an ecological information based alternative that can.

There is a recent literature in philosophy that has developed a taxonomy of scientific explanations for phenomena, the kinds of models we use, and the research programmes that produce the explanations and models. Roughly, there are two basic research programmes. The first programme takes some capacity of a system and maps out how it works by breaking it down into various sub-capacities, each with their own distinct characteristics. The end goal is a functional model, a ‘how-possibly’ box-and-arrow type explanation of how a capacity such as memory is organised. The second programme instead focuses on analytically decomposing a proposed mechanism that produces a phenomena into real parts and processes. Empirical work focuses on establishing that the proposed parts are part of the actual mechanism being modelled, and localising where those parts live and how they contribute to implementing the phenomena. The end goal is a dynamical mechanistic model, a ‘how-actually’ explanation in which each model part explicitly represents the dynamics of a real part or process. Mechanistic models, when they are possible to develop, are considered to be the best form of scientific explanation of a phenomena. Ecological psychology has, so far, widely resisted becoming a mechanistic science. This is in part due to our objections to mechanistic, Cartesian ontologies, and more recently because it’s not clear we can meaningfully decompose the systems we study in order to develop such models. I will argue here that both of these concerns are unfounded, that ecological psychology is actually perfectly capable of developing mechanistic models, and that therefore we should do so, in order to gain the benefits.

Interface theory is the hypothesis that inferential, representational theories of perception entail that fitness, not truth, dictates the evolution of perceptual systems. They show, with simulations, that “veridical” perceptual mappings (ones that preserve at least some of the structure of the world) are routinely out-competed by “non-veridical” interfaces (ones that make no attempt to preserve that structure). They therefore take particular aim at the direct perception, ecological approach to perception and work to show that such a system, even if technically an option, would never be selected for by evolution. This paper defends the ecological approach from this novel, existential attack by showing that the ecological hypothesis is so different in kind to the inferential, representational view of perception that it simply falls outside the scope of interface theory’s critiques; ecological psychology remains a viable scientific endeavor. This analysis will show that, far from being a radical new approach to perception, interface theory is simply a clear and elegant formalization of mainstream representational psychology, and any implications interface theory may have belong solely to that branch of science.

Spheroids are ball-shaped stone objects found in African archaeological sites dating from 1.8 million years ago (Early Stone Age) to at least 70,000 years ago (Middle Stone Age). Spheroids are either fabricated or naturally shaped stones selected and transported to places of use making them one of the longest-used technologies on record. Most hypotheses about their use suggest they were percussive tools for shaping or grinding other materials. However, their size and spherical shape make them potentially useful as projectile weapons, a property that, uniquely, humans have been specialised to exploit for millions of years. Here we show (using simulations of projectile motions resulting from human throwing) that 81% of a sample of spheroids from the late Acheulean (Bed 3) at the Cave of Hearths, South Africa afford being thrown so as to inflict worthwhile damage to a medium-sized animal over distances up to 25 m. Most of the objects have weights that produce optimal levels of damage from throwing, rather than simply being as heavy as possible (as would suit other functions). Our results show that these objects were eminently suitable for throwing, and demonstrate how empirical research on behavioural tasks can inform and constrain our theories about prehistoric artefacts.

The pain in Fibromyalgia (FM) is difficult to treat and functional mobility seems to be an important comorbidity in these patients that could evolve into a disability. In this study we wanted to investigate the analgesic effects of music in FM pain. Twenty-two FM patients were passively exposed to (1) self-chosen, relaxing, pleasant music, and to (2) a control auditory condition (pink noise). They rated pain and performed the "timed-up & go task (TUG)" to measure functional mobility after each auditory condition. Listening to relaxing, pleasant, self-chosen music reduced pain and increased functional mobility significantly in our FM patients. The music-induced analgesia was significantly correlated with the TUG scores; thereby suggesting that the reduction in pain unpleasantness increased functional mobility. Notably, this mobility improvement was obtained with music played prior to the motor task (not during), therefore the effect cannot be explained merely by motor entrainment to a fast rhythm. Cognitive and emotional mechanisms seem to be central to music-induced analgesia. Our findings encourage the use of music as a treatment adjuvant to reduce chronic pain in FM and increase functional mobility thereby reducing the risk of disability.

Under certain conditions, learning can transfer from a trained task to an untrained version of that same task. However, it is as yet unclear what those certain conditions are or why learning transfers when it does. Coordinated rhythmic movement is a valuable model system for investigating transfer because we have a model of the underlying task dynamic that includes perceptual coupling between the limbs being coordinated. The model predicts that (1) coordinated rhythmic movements, both bimanual and unimanual, are organised with respect to relative motion information for relative phase in the coupling function, (2) unimanual is less stable than bimanual coordination because the coupling is unidirectional rather than bidirectional, and (3) learning a new coordination is primarily about learning to perceive and use the relevant information which, with equal perceptual improvement due to training, yields equal transfer of learning from bimanual to unimanual coordination and vice versa [but, given prediction (2), the resulting performance is also conditioned by the intrinsic stability of each task]. In the present study, two groups were trained to produce 90° either unimanually or bimanually, respectively, and tested in respect to learning (namely improved performance in the trained 90° coordination task and improved visual discrimination of 90°) and transfer of learning (to the other, untrained 90° coordination task). Both groups improved in the task condition in which they were trained and in their ability to visually discriminate 90°, and this learning transferred to the untrained condition. When scaled by the relative intrinsic stability of each task, transfer levels were found to be equal. The results are discussed in the context of the perception–action approach to learning and performance.

Bingham (2001; 2004a,b) proposed a dynamical model of coordinated rhythmic movement that predicted the information used was the relative direction of motion, modified by relative speed. de Rugy et al (2008) tested this prediction by testing the dependence on speed. They reported that movement stability did not depend on relative speed. However, there were limitations that cast doubt on these findings. First, the only reported measure was of stability. It quantified consistency but not accuracy. Second, amplitude, manipulated to alter relative speed, was not reported. Whether required differences in speed were actually generated is unknown. Finally, the task used to test the model was not one the model was designed to represent. We ran the following studies to test Bingham's hypothesis more precisely. Participants used a joystick to coordinate the movement of two dots on a screen, controlled by computer and joystick respectively. First, we tested stability using the ‘switching’ paradigm. Participants attempted to produce 180° relative phase at frequencies increasing from 0.5Hz to 2.0Hz by 0.25Hz steps. Switching occurred at 1.25Hz. Visual coordination is much less stable than bimanual coordination. Next, we assessed movement stability at 0° and 180° by having participants move at 1.0Hz, 1.25Hz and 1.50Hz. The amplitude of the joystick dot was constant while that of the computer dot was either the same or three times larger. 0° with unequal amplitudes had the same relative speed difference as 180° with equal amplitudes; so, the stability should be comparable and less than 0° with equal amplitudes. Using a measure of both consistency and accuracy, we found that speed differences affected movement stability as predicted by the Bingham hypothesis (even though amplitudes were somewhat different than required). Bingham, Snapp-Childs and Wilson (submitted) revised the model for the new task and successfully captured these results.

A common perception-action learning task is to teach participants to produce a novel coordinated rhythmic movement, e.g. 90 degrees mean relative phase. As a general rule, people cannot produce these novel movements stably without training. This is because they are extremely poor at discriminating the perceptual information required to coordinate and control the movement, which means people require additional (augmented) feedback to learn the novel task. Extant methods (e.g. visual metronomes, Lissajous figures) work, but all involve transforming the perceptual information about the task and thus altering the perception-action task dynamic being studied. We describe and test a new method for providing online augmented coordination feedback using a neutral colour cue. This does not alter the perceptual information or the overall task dynamic, and an experiment confirms that (a) feedback is required for learning a novel coordination and (b) the new feedback method provides the necessary assistance. This task-appropriate augmented feedback therefore allows us to study the process of learning while preserving the perceptual information that constitutes a key part of the task dynamic being studied. This method is inspired by and supports a fully perception-action approach to coordinated rhythmic movement.

Recent behavioural research has investigated whether viewing someone perform an action results in activation of that action by the observer. Postulated empirical support for this 'ideo-motor (IM) conjecture' typically rests upon two types of experimental paradigm (reaction time and movement tracking tasks). These paradigms purport to show movement facilitation when compatible movements are observed and vice versa, but only for biological stimuli. Unfortunately, these paradigms often contain confounding (and unavoidable) generic stimulus-response compatibility effects that are not restricted to observed human movement. The current study demonstrates in three experiments that equivalent compatibility effects can be produced by non-biological stimuli. These results suggest that existing empirical paradigms may not, and perhaps cannot, support the IM-conjecture. © 2007 Springer-Verlag.

Following many studies showing that the coupling in bimanual coordination can be perceptual, Bingham (Ecol Psychol in 16:45-53, 2001; 2004a, b) proposed a dynamical model of such movements. The model contains three key hypotheses: (1) Being able to produce stable coordinative movements is a function of the ability to perceive relative phase, (2) the information to perceive relative phase is relative direction of motion, and (3) the ability to resolve this information is conditioned by relative speed. The first two hypotheses have been well supported (Wilson and Bingham in Percept Psychophys 70:465-476, 2008; Wilson et al. in J Exp Psychol Hum 36:1508-1514, 2010a), but the third was not supported when tested by de Rugy et al. (Exp Brain Res 184:269-273, 2008) using a visual coordination task that required simultaneous control of both the amplitude and relative phase of movement. The purposes of the current study were to replicate this task with additional measures and to modify the original model to apply it to the new task. To do this, we conducted two experiments. First, we tested the ability to produce 180° visual coordination at different frequencies to determine frequencies suitable for testing in the de Rugy et al. task. Second, we tested the de Rugy et al. task but included additional measures that yielded results different from those reported by de Rugy et al. These results were used to elaborate the original model. First, one of the phase-driven oscillators was replaced with a harmonic oscillator, so the resulting coupling was unidirectional. This change resulted in the model producing less stable 180°coordination behavior beyond 1.5 Hz consistent with the results obtained in Experiment 1. Next, amplitude control and phase correction elements were added to the model. With these changes, the model reproduced behaviors observed in Experiment 2. The central finding was that the stability of rhythmic movement coordination does depend on relative speed and, thus, all three of the hypotheses contained in the original Bingham model are supported. © 2011 Springer-Verlag.

The Masked Priming Toolbox is an open-source collection of MATLAB functions that utilizes the free third-party PsychToolbox-3 (PTB3: Brainard, Spatial Vision, 10, 433-436, 1997; Kleiner, Brainard & Pelli, Perception, 36, 2007; Pelli, Spatial Vision, 10, 437-442, 1997). It is designed to allow a researcher to run masked (and unmasked) priming experiments using a variety of response devices (including keyboards, graphics tablets and force transducers). Very little knowledge of MATLAB is required; experiments are generated by creating a text file with the required parameters, and raw and analyzed data are output to Excel (as well as MATLAB) files for further analysis. The toolbox implements a variety of stimuli for use as primes and targets, as well as a variety of masks. Timing, size, location, and orientation of stimuli are all parameterizable. The code is open-source and made available on the Web under a Creative Commons License. © 2010 Psychonomic Society, Inc.

This commentary is on the original article by King et al. on pages 932‐937 of this issue.

Human arm movements need 'online' corrections due to noise in perception and action. A Step-Perturbation paradigm explored online corrections in control children and children with DCD aged between 7 and 13 years. Control children found the task straightforward: a distracter had no effect and they managed to stop relatively quickly. Children with DCD found the task difficult and the apparatus was modified accordingly (decreased postural and force production demands). The distracter affected some children with DCD and some found it difficult to stop. All of the DCD population showed poorer performance in both the perturbation and non-perturbation condition. Nevertheless, there was no interaction between group and condition. Thus, this study found no evidence for specific deficits in online correction mechanisms in DCD. We suggest that: (i) fundamental problems in generating basic movements can account for the documented difficulties in correcting on-going movements, and (ii) such fundamental difficulties make it very difficult to pinpoint specific mechanism deficits. © 2008 Elsevier B.V. All rights reserved.

The production and perception of coordinated rhythmic movement are very specifically structured. For production and perception, 0° mean relative phase is stable, 180° is less stable, and no other state is stable without training. It has been hypothesized that perceptual stability characteristics underpin the movement stability characteristics, which has led to the development of a phase-driven oscillator model (e.g., Bingham, 2004a, 2004b). In the present study, a novel perturbation method was used to explore the identity of the perceptual information being used in rhythmic movement tasks. In the three conditions, relative position, relative speed, and frequency (variables motivated by the model) were selectively perturbed. Ten participants performed a judgment task to identify 0° or 180° under these perturbation conditions, and 8 participants who had been trained to visually discriminate 90° performed the task with perturbed 90° displays. Discrimination of 0° and 180° was unperturbed in 7 out of the 10 participants, but discrimination of 90° was completely disrupted by the position perturbation and was made noisy by the frequency perturbation. We concluded that (1) the information used by most observers to perceive relative phase at 0° and 180° was relative direction and (2) becoming an expert perceiver of 90° entails learning a new variable composed of position and speed. Copyright 2008 Psychonomic Society, Inc.

Previous work has established that judgments of relative phase variability of 2 visually presented oscillators covary with mean relative phase. Ninety degrees is judged to be more variable than 0° or 180°, independently of the actual level of phase variability. Judged levels of variability also increase at 180°. This pattern of judgments matches the pattern of movement coordination results. Here, participants judged the phase variability of their own finger movements, which they generated by actively tracking a manipulandum moving at 0°, 90°, or 180°, and with 1 of 4 levels of Phase Variability. Judgments covaried as an inverted U-shaped function of mean relative phase. With an increase in frequency, 180° was judged more variable whereas 0° was not. Higher frequency also reduced discrimination of the levels of Phase Variability. This matching of the proprioceptive and visual results, and of both to movement results, supports the hypothesized role of online perception in the coupling of limb movements. Differences in the 2 cases are discussed as due primarily to the different sensitivities of the systems to the information.

Coordinated rhythmic movement is specifically structured in humans. Movement at 0° mean relative phase is maximally stable, 180° is less stable, and other coordinations can, but must, be learned. Variations in perceptual ability play a key role in determining the observed stabilities so we investigated whether stable movements can be acquired by improving perceptual ability. We assessed movement stability in Baseline, Post Training, and Retention sessions by having participants use a joystick to coordinate the movement of two dots on a screen at three relative phases. Perceptual ability was also assessed using a two-alternative forced choice task in which participants identified a target phase of 90° in a pair of displays. Participants then trained with progressively harder perceptual discriminations around 90° with feedback. Improved perceptual discrimination of 90° led to improved performance in the movement task at 90° with no training in the movement task. The improvement persisted until Retention without further exposure to either task. A control group's movement stability did not improve. Movement stability is a function of perceptual ability, and information is an integral part of the organization of this dynamical system.

The effect of advance ('precue') information on short aiming movements was explored in adults, high school children, and primary school children with and without developmental coordination disorder (n = 10, 14, 16, 10, respectively). Reaction times in the DCD group were longer than in the other groups and were more influenced by the extent to which the precue constrained the possible action space. In contrast, reaction time did not alter as a function of precue condition in adults. Children with DCD showed greater inaccuracy of response (despite the increased RT). We suggest that the different precue effects reflect differences in the relative benefits of priming an action prior to definitive information about the movement goal. The benefits are an interacting function of the task and the skill level of the individual. Our experiment shows that children with DCD gain a benefit from advance preparation in simple aiming movements, highlighting their low skill levels. This result suggests that goal-directed RTs may have diagnostic potential within the clinic. © 2008 Elsevier B.V. All rights reserved.

AIM: This study investigated the nature of coordination and control problems in children with developmental coordination disorder (DCD). METHOD: Seven adults (two males, five females, age range 20–28y; mean 23y, SD 2y 8mo) and eight children with DCD (six males, two females, age range 7–9y; mean 8y, SD 8mo), and 10 without DCD (seven males, three females, age range 7–9y; mean 8y, SD 7mo) sat in a swivel chair and looked at or pointed to targets. Optoelectronic apparatus recorded head, torso, and hand movements, and the spatial and temporal characteristics of the movements were computed. RESULTS: Head movement times were longer (p<0.05) in children with DCD than in the comparison group, even in the looking task, suggesting that these children experience problems at the lowest level of coordination (the coupling of synergistic muscle groups within a single degree of freedom). Increasing the task demands with the pointing condition affected the performance of children with DCD to a much greater extent than the other groups, most noticeably in key feedforward kinematic landmarks. Temporal coordination data indicated that all three groups attempted to produce similar movement patterns to each other, but that the children with DCD were much less successful than age-matched children in the comparison group. INTERPRETATION: Children with DCD have difficulty coordinating and controlling single degree-of-freedom movements; this problem makes more complex tasks disproportionately difficult for them. Quantitative analysis of kinematics provides key insights into the nature of the problems faced by children with DCD.

Target distance affects movement duration in aiming tasks but its effect on reaction time (RT) is poorly documented. RT is a function of both preparation and initiation. Experiment 1 pre-cued movement (allowing advanced preparation) and found no influence of distance on RT. Thus, target distance does not affect initiation time. Experiment 2 removed pre-cue information and found that preparing a movement of increased distance lengthens RT. Experiment 3 explored movements to targets of cued size at non-cued distances and found size altered peak speed and movement duration but RT was influenced by distance alone. Thus, amplitude influences preparation time (for reasons other than altered duration) but not initiation time. We hypothesise that the RT distance effect might be due to the increased number of possible trajectories associated with further targets: a hypothesis that can be tested in future experiments. © 2007 Springer-Verlag.

This study examined perception-action learning in younger adults in their 20s compared to older adults in their 70s and 80s. The goal was to provide, for the first time, quantitative estimates of perceptuo-motor learning rates for each age group and to reveal how these learning rates change between these age groups. We used a visual coordination task in which participants are asked to learn to produce a novel-coordinated rhythmic movement. The task has been studied extensively in young adults, and the characteristics of the task are well understood. All groups showed improvement, although learning rates for those in their 70s and 80s were half the rate for those in their 20s. We consider the potential causes of these differences in learning rates by examining performance across the different coordination patterns examined as well as recent results that reveal age-related deficits in motion perception. © 2012 Springer-Verlag Berlin Heidelberg.

The authors studied 2 tasks that placed differing demands on detecting relevant visual information and generating appropriate gaze shifts in adults and children with and without autism. In Experiment 1, participants fixated a cross and needed to make large gaze shifts, but researchers provided explicit instructions about shifting. Children with autism were indistinguishable from comparison groups in this top-down task. In Experiment 2 (bottom-up), a fixation cross remained or was removed prior to the presentation of a peripheral target of low visual salience. In this gap-effect experiment, children with autism showed lengthened reaction times overall but no specific deficit in overlap trials. The results show evidence of a general deficit in manual responses to visual stimuli of low salience and no evidence of a deficit in top-down attention shifting. Older children with autism appeared able to generate appropriate motor responses, but stimulus-driven visual attention seemed impaired. © 2009 Heldref Publications.

Ideomotor (IM) theory suggests that observing someone else perform an action activates an internal motor representation of that behaviour within the observer. Evidence supporting the case for an ideomotor theory of imitation has come from studies that show imitative responses to be faster than the same behavioural measures performed in response to spatial cues. In an attempt to replicate these findings, we manipulated the salience of the visual cue and found that we could reverse the advantage of the imitative cue over the spatial cue. We suggest that participants utilised a simple visuomotor mechanism to perform all aspects of this task, with performance being driven by the relative visual salience of the stimuli. Imitation is a more complex motor skill that would constitute an inefficient strategy for rapid performance. © 2006 Elsevier Inc. All rights reserved.

Introduction: Many perceptual-motor tasks require rhythmic movements of limbs, pendulums, or display stimuli, with specific relative timing. People can generally only produce two stable coordination patterns without training: 0 deg and 180 deg. Others (e.g., 90 deg) usually have to be learned. Surprisingly, there are no major studies of rhythmic coordination learning across the lifespan. As part of a larger study, here we compare the learning of younger (20 years) and older (60, 70, 80 years) adults. Methods: We presented two vertically displaced white dots against a black background. The computer controlled the top dot and the participant controlled the bottom dot via a joystick. Sessions involved the target phase relationship being displayed before participants attempted to produce the same coordinative pattern. There were three assessment sessions (baseline, post-training, retention × 4 trials = 12 total) with 0, 180, and 90 deg, and five training sessions (10 trials) with only 90 deg. Feedback was provided in training by changing the person-controlled dot from white to green when the participant was moving at 90 deg ± an error band that decreased as performance improved. Results: All groups improved significantly across training and this was generally retained post-training. Nonetheless, learning rates were different between groups and decreased with age, with the older adults also showing highly variable performance. The introduction of feedback immediately improved performance in the young but not older adults. Discussion: The older adults showed reduced learning rates although the age of steepest decline has yet to be determined. The immediate improvement of the young with the introduction of the green dot implies the feedback usefully constrained the state space and thus allowed them to become attuned to the relevant perceptual variables—and therefore learn rapidly. In contrast, feedback was less useful for the older participants suggesting the state space remained relatively unconstrained with the negative consequences reflected in the learning rates.

When primed by backward-masked, target-like stimuli, discrete responses (e.g. button presses) to simple visual targets can be slower when prime and target match (compatible) than when they do not (incompatible). The current study investigated the nature of the stimulus-response mapping underlying this negative compatibility effect (NCE). Discrete left-right responses to arrow targets were primed with arrows oriented in one of 16 directions. Responses were either a standard button press or a 10 cm movement on a graphics tablet. Both tasks showed an identical NCE; importantly, reaction times in both tasks decreased smoothly as the angular distance between prime and target increased (i.e. as compatibility decreased), with the largest NCE evident between the extreme cases (prime-target distances of 0 degrees and 180 degrees ). Primes exerted an effect on the required response in proportion to the amount of overlap (reflecting population vector coding). The mapping between the priming stimulus and response is continuous, not categorical.

Introduction: Many perceptual-motor tasks require rhythmic movements of limbs, pendulums, or display stimuli, with specific relative timing. People can generally only produce two stable coordination patterns without training: 0° and 180°. Others (e.g. 90°) usually have to be learned. Surprisingly, there are no major studies of rhythmic coordination learning across the lifespan. As part of a larger study, here we compare the learning of younger (20 years) and older (60, 70, 80 years) adults. Method: We presented two vertically displaced white dots against a black background. The computer controlled the top dot and the participant controlled the bottom dot via a joystick. Sessions involved the target phase relationship being displayed before participants attempted to produce the same coordinative pattern. There were three assessment sessions (Baseline, Post-training, Retention × 4 trials = 12 total) with 0°, 180° and 90°, and five training sessions (10 trials) with only 90°. Feedback was provided in training by changing the person-controlled dot from white to green when the participant was moving at 90°± an error band that decreased as performance improved. Results: All groups improved significantly across training and this was generally retained post-training. Nonetheless, learning rates were different between groups and decreased with age, with the older adults also showing highly variable performance. The introduction of feedback immediately improved performance in the young but not older adults. Discussion: The older adults showed reduced learning rates although the age of steepest decline has yet to be determined. The immediate improvement of the young with the introduction of the green dot implies the feedback usefully constrained the state space and thus allowed them to become attuned to the relevant perceptual variables - and therefore learn rapidly. In contrast, feedback was less useful for the older participants suggesting the state space remained relatively unconstrained with the negative consequences reflected in the learning rates.

Prior to training, only two coordinated rhythmic movements are stable: 0° and 180°. Other coordinations (e.g. 90°) must be learned. This pattern emerges from a task dynamic in which relative phase is perceived as the relative direction of motion, modified by the relative speed (Bingham, 2004). People can learn how to move at 90° but this entails learning to use a different information variable (relative position; Wilson & Bingham, 2008). Learning a novel coordination requires feedback, however, and typically this feedback is presented in the form of a transformed display such as a Lissajous plot. This display removes relative motion of any kind as a source of information about relative phase and simply requires people to track a template; as a result, people can move at any required coordination with brief practice. Wilson et al (2010) developed a second form of feedback, coordination feedback, which doesn’t alter the information available for relative phase and preserves relative position as an option. The current study directly compared the two feedback methods. 12 participants learned to move bimanually at 90° using either Lissajous (N=6) or coordination (N=6) feedback. We tested coordination stability with both displays in baseline, post training and retention sessions, with baseline and post training separated by 5 training sessions. Both feedback methods improved performance at 90°, but there was no transfer of this learning between the feedback displays. The two feedback methods create different task dynamics that are informationally distinct from one another, and participants learned to use different information to support their actions. This result confirms that a) the two feedback methods provide different perceptual information and that b) perceptual learning underpins the improvements in movement stability, even in the bimanual version of the task. Information is a key part of a perception-action analysis of this task (Bingham, 2004).

Introduction Throwing to hit distant targets requires perception of target distance and height. This information must then be used to control both release angle and speed of the projectile. These two action parameters trade off to allow target hits. Some regions of the parameter space yield greater latitude in parameters that yield a hit, affording the most reliable performance. Do expert performers perceive this affordance to operate in these more stable regions? Methods We tested expert throwers in two studies. Participants threw balls to hit a 4ft x 4ft vertical target. In Experiment 1, we manipulated target distance (5m, 10m, 15m) and height (1m, 1.5m, 2m). In Experiment 2, we manipulated target distance (5m, 10m, 15m), orientation (vertical, horizontal), and vision (monocular, binocular). We performed dynamical simulations of hit/miss across a wide range of release parameters to map stability in the task space. We then mapped the experts’ performance within this space. Results For vertical targets, release speeds were high and scaled with distance. Release angles were low and scaled with both distance and height. The horizontal target then forced experts to throw high and slow, which they readily did. Monocular vision only affected throws to vertical targets; poorer resolution of distance yielded slower throws compensated for by increased angles. Dense simulation of the parameter space allowed us to quantify the affordances. Experts do operate in regions of the space with optimal stability (i.e. hits over wide variation in release angle). Conclusion The dynamics of throwing to distant targets yield a task space specified in terms of two action parameters, release angle and speed, that determine successful action. Mapping the structure of this space reveals regions affording reliably successful performance. Expert throwers exhibited sensitivity to this affordance, performing within these more stable regions.

Introduction Many perceptuo-motor tasks require coordinated rhythmic movements of different limbs. People can only produce two stable coordination patterns without training: 0[sup]0[/sup] and 180[sup]0[/sup]. Others (e.g. 90[sup]0[/sup]) usually have to be learned. Surprisingly, there are no major studies of such learning across the lifespan. In 2010, we presented data from 20, 70 and 80 year olds. Here we present data from all decades from 20 to 80. Method ~10 participants in each decade from 20s through 80s took part. Two vertically displaced white dots appeared in a display against a black background. The computer controlled the top dot and the participant the bottom one using a joystick. The target coordinative pattern was displayed before participants attempted to produce it. There were three assessment sessions (Baseline, Post-training, Retention) each containing 12 trials (4 x 0[sup]0[/sup], 180[sup]0[/sup] and 90[sup]0[/sup]) and five training sessions (each 10 x 90[sup]0[/sup]). During training, feedback was provided by changing the dots from white to green when the movement was at 90[sup]0[/sup]± an error band that decreased as performance improved. Results All groups improved with training and all retained it except 60 year olds. An exponential model was fit to learning curves using two methods to yield convergent measures of learning rates that were found to decrease with age with modest decline until a steep drop after 50. Statistical analyses confirmed this picture. Overall, learning rates dropped by half. Conclusions Although adults over 60 learn, they do so at half the rate. Programs for recovery from stroke and other conditions should respect these reduced yet effective learning rates. Multiple factors are likely responsible for the learning deficit that comes with age, but motion perception is likely to be a key factor in this case, and the 50s is the crucial decade.

Roger Shepard's description of an abstract representational space defined by landmark objects and kinematic transformations between them fails to successfully capture the essence of the perceptual tasks he expects of it, such as object recognition. Ultimately, objects are recognized in the context of events. The dynamic nature of events is what determines the perceived kinematic behavior, and it is at the level of dynamics that events can be classified as types.

In human movement coordination 0° and 180° mean relative phase (MRP) are the only spontaneously stable states, with 0° more stable than 180°. Our research focuses on the role of perceptual information in producing this pattern, specifically perceived phase. With both visual (e.g. Zaal, Bingham & Schmidt, 2000) and haptic (Wilson, Bingham & Craig, submitted) phase information, 180° was judged as intrinsically more variable than 0°, and at other MRPs, added variability was not discriminated. This motivated a new model of rhythmic movement coordination (Bingham, 2001; Bingham & Collins, submitted) in which (non-linear autonomous) oscillators are driven and coupled by perceived phases. The current research separates the contributions of visually and haptically perceived phase in a movement coordination task. Participants moved a joystick to maintain a visual MRP of 0° between 2 dots on a screen, joystick and computer controlled respectively. The mapping between the joystick and its dot was manipulated to be either 0° (labeled 0/0) or 180° (0/180). We hypothesized that participants would be able to discriminate small variations from the intended visual MRP of 0° and use this to drive stable performance. In both cases participants maintained visual MRP close to 0° (-14.9° for 0/0, -17° for 0/180). Stable visual perception of 0° did indeed stabilize the movement. However, 0/180 (mean vector length (MVL) = 0.45) was more variable than 0/0 (MVL=0.58, where a larger MVL denotes less variable data). Additionally, a control case in which participants moved at 180 to produce 180 visually (180/180), demonstrated that participants could not do this as stably as 0/180 (MRP = 149.5°, MVL = 0.36). The haptic MRP was still having an effect consistent with the movement stability pattern. Results are discussed in terms of the relative contributions of visually and haptically perceived phase to the performance of coordinated movement.

The present invention concerns apparatus for the detection and/or assessment of neurodevelopmental disorders of a user, the apparatus comprising: control means for providing a goal-orientated task to a display, said task being formulated to elicit a movement from a user in response to said task; input means via which a user can input a response to said task; wherein said control means records a user ' s response as multi-dimensional input data, which can be used to profile the user for the presence or absence of a neurodevelopmental disorder, the task being specifically formulated such that indicative characteristics of a user' s movement over time can be identified by said multi-dimensional input data.

Introduction The Common Coding Theory (Prinz, 1997; Hommel et al., 2001) suggests that perception and action share a common representation and hypothesizes accordingly: 1) people should better perceive motions that are produced by their own action; 2) people should better perceive actions at which they are skilled. We now test these hypotheses using point-light displays of experts throwing to hit targets at different distances and heights. Methods Using videos of 6 experts throwing to hit targets at 3 distances (5m, 10m, 15m) and 3 heights (.5m, 1m, 1.5m) 5 times each, we created 45 point-light displays for expert and novice throwers to judge the distance and height of targets. Point lights were attached to 7 major joints of the thrower including the ball and only throwing motion was displayed up to ball release. Expert and novice throwers judged displays of throws by other experts. Experts also judged displays of themselves. Results All observers were well above chance in judging distance (54.8%±8.1>33.3%), height (51.4%±8.6>33.3%) and both (28.6%±9>11.1%). A repeated-measures ANOVA on expert judgments testing identity (self, other) was significant for distance (F1,5 = 8.66, p<0.05, self: 52%, other: 62%), and for height (F1,5 = 9.31 , p<0.05, self: 48%, other: 56%). Other was always judged better than self! A factorial ANOVA on judgments of other testing skill level (expert, novice) was significant for distance (F1,10 = 9.55, p <0.01, experts: 62%, novices: 50%), but not for height (p>0.05, experts: 56%, novices: 50%). Conclusion The first hypothesis was rejected because experts judging other were better than they judging self. The second hypothesis was only partly supported because experts judging other were better than novices judging other only in respect to distance, not height.

When we see an object in the world, there may be a large number of different ways to interact with that object. This large ‘visuomotor space’ can be constrained through affordances (perceptually available object properties defining potential uses), task demands and the actor's intentions. The effects of perceptual biases can be modified by performance factors, such as a limb's end-state-comfort (ESC; Rosenbaum et al. 1990). We investigated how two other potential performance biases affected interaction with a perceptually under-constrained object: hysteresis (H) and minimal forearm rotation (MR). Experiment 1 found H and MR operating in adult participants who reached-to-grasp a doweling placed at different orientations either randomly or systematically (orientation changed by 30° every five reaches either clockwise or counter-clockwise). In the random condition, participants switched between pronation and supination depending on which required minimum forearm rotation, but a systematic reach history delayed the transition from pronation to supination in the counter-clockwise condition (and vice versa). This effect was more pronounced in 5–15 year old children. Experiment 2 placed ESC and MR in opposition. Participants reached-to-grasp a doweling at one of two initial orientations and rotated it clockwise or counter-clockwise by 180°. On half the trials, ESC could only be achieved at the expense of MR. Adults reliably acted to achieve ESC when reaching with their preferred hand (100% of trials but less so with the non-preferred hand at circa 80%). Younger children (5–8 years) and children with developmental coordination disorder (5–13 years) were primarily driven by MR and to a lesser extent H. Older children (9–13 years) showed a clear developmental trend towards adult behaviour. Thus, action selection is a dynamic process subject to numerous performance biases even in skilled adult participants. Importantly, the effect of performance biases on perceptually under-constrained objects varies with skill level and developmental status.

Background. Overt attention shifts are made through eye, head, and torso rotations or some combination thereof. Many studies have explored eye-head coordination but relatively few studies have investigated head-torso coordination. We explored head-torso coordination using a looking and pointing task. Head-torso coordination involves complex dynamics and we hypothesised that the coordinative behaviour would demonstrate hysteresis (where history influences behaviour) in common with most complex systems. Methods. Eight right-handed adults sat in a swivel chair and both looked and pointed eight times over a 180° range to eighteen different locations in 10° increments right and left of midline (conditions counter-balanced, target locations randomised). Optoelectronic apparatus recorded head, torso, and hand movements. The positional data were subsequently filtered and differentiated to provide detailed kinematic profiles. Results. (1) The head, torso, and hand speed profiles unfolded within a common time window enveloped by the head movement duration. Head peak speed had a linear relationship with target angle. Movement time also had a linear relationship with target angle until a plateau around 60°. (2) Even small gaze shifts (10° from the midline) involved changes in head position, which contrasts with previous studies reporting that small gaze shifts only involve the eyes. Whilst participants sometimes pointed at targets on the right hand side without torso rotation, the number of trials with torso rotation increased linearly with angle. There were twice as many trials with torso rotation to the right side targets in the pointing condition when compared to the looking condition. Conclusion. A reliable relationship exists between speed and amplitude in head movements. A flexible task dependent coordinative relationship exists between the head, torso, and hand. The coordinative relationship cannot be predicted simply from the task - it is necessary to know the history of the system. Thus, the head-torso system exhibits hysteresis as hypothesised.

Background: Coordinated rhythmic movement is specifically structured in humans. Movement at 0° mean relative phase is maximally stable; movement at 180° is less stable; and no other relative phase is stable without training. Previous work has demonstrated this pattern in perceptual judgment tasks, and also that perceptual feedback manipulations affect movement stability. These results are seen as evidence that perception plays a key role in determining the coordinated movement stabilities. Methods: Stable movement at other relative phases (e.g. 90°) can be acquired through practice of the movements. We investigated whether such stable movements can be acquired through perceptual learning. We first assessed Baseline movement stability at 0°, 90° and 180° by having participants use a joystick to coordinate the movement of two dots on a screen at the three phases. Perceptual stability at 90° and 180° was assessed with a 2-alternative forced choice (2AFC) task in which participants identified the target phase from a pair of displays. Participants then practiced to improve their perceptual resolution of 90° by making progressively harder discriminations, with feedback. We then assessed movement and perceptual stability in Post Training and Retention sessions. Results: Improved perceptual discrimination of 90° immediately led to improved performance in the 90° movement task without any motor training. The improvement persisted between Post Training and Retention without further task exposure. Movement stability at 90° for a control group (movement assessment only) did not improve. Conclusions: Movement stability is a function of perceptual stability - improving the latter improves the former. Perceptual information is an integral part of the organization of this dynamical system.

Bingham (2001; 2004a,b) proposed a dynamical model of coordinated rhythmic movement that predicted the information used was the relative direction of motion, modified by relative speed. de Rugy et al (2008) tested this prediction by testing the dependence on speed. They reported that movement stability did not depend on relative speed. However, there were limitations that cast doubt on these findings. Among them was the fact that the task used to test the model was not one the model was designed to represent. Snapp-Childs, Wilson and Bingham (submitted) replicated de Rugy et al.'s experiment and obtained results that supported the Bingham information hypothesis in contrast to the finding of de Rugy et al. We now revise the original Bingham model to apply to this new task, and then compare simulated data to the Snapp-Childs et al. data. To adapt the model to the new task, it had to be revised in three respects. First, the visual coordination task entailed uni-directional (not bi-directional) visual coupling. The revised model was used to simulate the switching experiment of Snapp-Childs et al successfully. Uni-directional coupling yielded a less stable system that switched at 1.25Hz rather than 3-4Hz. Second, the task required participants to control and produce specific amplitudes of movement (as well as specific frequencies and relative phases). This entailed another information variable, specifying amplitude, to be incorporated into the dynamical model to control and produce required amplitudes. Third, the task required that participants correct spontaneous deviations from required relative phases. The original Bingham model included perceived relative phase. This was now used to detect departures from required phases and to perform corrections. The resulting model successfully simulated the results replicated in Snapp-Childs et al. illustrating emphatically that perception-action models are required to model performance in coordinated rhythmic movement tasks.

Abstract We propose that people can and will infer group memberships from resource distributions, and that these distributions have implications for people's understandings of the groups themselves and their own associations with these groups. We derive hypotheses from social identity and self‐categorization theories, and test them in three experiments. In Experiment 1, participants systematically rated specific patterns of group memberships as more likely than others in light of specific resource distributions in a manner consistent with our predictions. In Experiment 2, intragroup distributive fairness led to greater perceived self‐in‐group similarity than intra‐group distributive unfairness, while distributively unfair, in‐group favouritism led to greater perceived self‐in‐group similarity than intergroup fairness. In Experiment 3, social identification dropped following unfair, out‐group favouritism and intragroup unfairness, but not unfair, in‐group favouritism, or intragroup and intergroup fairness. The current data provide support for our hypotheses and clear evidence that resource distributions can be providers of group membership information. Copyright © 2007 John Wiley & Sons, Ltd.

Rhythmic movement coordination exhibits characteristic patterns of stability, specifically that movements at 0° mean relative phase are maximally stable, 180° is stable but less so than 0°, and other coordinations are unstable without training. Recent research has demonstrated a role for perception in creating this pattern; perceptual variability judgments covary with movement variability results. This suggests that the movement results could be due in part to differential perceptual resolution of the target movement coordinations. The current study used a paradigm that enabled simultaneous access to both perception (between-trial) and movement (within-trial) stability measures. A visually specified 0° target mean relative phase enabled participants to produce stable movements when the movements were at a non-0° relationship to the target being tracked. Strong relationships were found between within-trial stability (the traditional movement measure) and between-trial stability (the traditional perceptual judgment measure), suggestive of a role for perception in producing coordination stability phenomena. The stabilization was incomplete, however, indicating that visual perception was not the sole determinant of movement stability. Rhythmic movement coordination is intrinsically a perception/action system. © Springer-Verlag 2005.

The current studies explore the informational basis of the coupling in human rhythmic movement coordination tasks. Movement stability in these tasks is an asymmetric U-shaped function of mean relative phase; 0° is maximally stable, 90° is maximally unstable and 180° is intermediate. Bingham (2001, 2004a, 2004b) hypothesized that the information used to perform coordinated rhythmic movement is the relative direction of movement, the resolution of which is determined by relative speed. We used an experimental paradigm that entails using a circular movement to produce a linear motion of a dot on a screen, which must then be coordinated with a linearly moving computer controlled dot. This adds a component to the movement that is orthogonal to the display. Relative direction is not uniquely defined between orthogonal components of motion, but relative speed is; it was therefore predicted that the addition of the component would only introduce a symmetric noise component and not otherwise contribute to the U-shape structure of movement stability. Results for experiment 1 supported the hypothesis; movement that involved the additional component was overall less stable than movement that involved only the parallel component along which relative direction can be defined. Two additional studies ruled out alternative explanations for the pattern of data in experiment 1. Overall, the results strongly implicate relative direction as the information underlying performance in rhythmic movement coordination tasks. © Springer-Verlag 2005.

Action selection is subject to many biases. Immediate movement history is one such bias seen in young infants. Is this bias strong enough to affect adult behavior? Adult participants reached and grasped a cylinder positioned to require either pronation or supination of the hand. Successive cylinder positions changed either randomly or systematically between trials. Random positioning led to optimized economy of movement. In contrast, systematic changes in position biased action selection toward previously selected actions at the expense of movement economy. Thus, one switches to a new movement only when the savings outweigh the costs of the switch. Immediate movement history had an even larger influence on children aged 7-15 years. This suggests that switching costs are greater in children, which is consistent with their reduced grasping experience. The presence of this effect in adults suggests that immediate movement history exerts a more widespread and pervasive influence on patterns of action selection than researchers had previously recognized. © 2009 Taylor & Francis Group, LLC.

Grip selection tasks have been used to test "planning" in both autism and developmental coordination disorder (DCD). We differentiate between motor and executive planning and present a modified motor planning task. Participants grasped a cylinder in 1 of 2 orientations before turning it clockwise or anticlockwise. The rotation resulted in a comfortable final posture at the cost of a harder initial reaching action on 50% of trials. We hypothesized that grip selection would be dominated by motoric developmental status. Adults were always biased towards a comfortable end-state with their dominant hand, but occasionally ended uncomfortably with their nondominant hand. Most 9- to 14-year-olds with and without autism also showed this "end-state comfort" bias but only 50% of 5- to 8-year-olds. In contrast, children with DCD were biased towards selecting the simplest initial movement. Our results are best understood in terms of motor planning, with selection of an easier initial grip resulting from poor reach-to-grasp control rather than an executive planning deficit. The absence of differences between autism and controls may reflect the low demand this particular task places on executive planning. © 2010 American Psychological Association.

Michael T. Turvey will be known for his innovative scholarship and incisive thinking, but he also leaves a powerful legacy of community-building. The ecological community would not be what it is today without his leadership in carving out space for our field, his commitment to encouraging the next generation of scholars, and his earnest outreach to other disciplines. Reflecting on Turvey’s legacy, we would like to encourage us all to pick up this mantle by intentionally committing to grow our community through new connections to the rest of cognitive science. Historically, our community has not been seen as inviting; even interested fellow travelers have felt rebuffed by seemingly rigid adherence to radical theory. Thanks in large part to Turvey, ecological scientists know that what we strive for is rigor, not rigidity—disciplined thinking, not unthinking allegiance. Following Turvey’s example, we argue that openness and rigor can be complementary strengths that will promote even more vibrant ecological community in the coming decades. Turvey helped form our community and helped prove that we had a place in cognitive science; let’s commit to taking the next steps in growing that place and becoming a community that many others can come to call home.

Movement control faces a problem of redundancy. In general, there are more degrees of freedom available to solve a task than the task requires. This ‘degrees of freedom’ problem has been reframed as a ‘motor abundance’ feature, where the redundancy enables crucial flexibility. The balance between flexibility and control has been proposed to depend on synergies, lower-dimensional organisations of movement dynamics into systems that solve the task at hand. There are now several movement analysis methods designed to search for the signatures of synergies and a great deal of empirical evidence that synergies feature in movement control. However, while all these analysis methods rely on notions of ‘task’ to constrain movement solutions, none of them come with a formal theory of what a task is or how tasks are perceived. This paper proposes the hypothesis that tasks should be formalised as task-dynamical affordances, and that perceiving these affordances via specifying information is how they constrain synergy (effectivities) formation. I lay out the hypothesis, and detail a research programme to investigate the hypothesis, with reference to existing work on throwing.

Movement control faces a problem of redundancy. In general, there are more degrees of freedom available to solve a task than the task requires. This ‘degrees of freedom’ problem has been reframed as a ‘motor abundance’ feature (Latash, 2012), where the redundancy enables crucial flexibility. The balance between flexibility and control has been proposed to depend on synergies, which are lower-dimensional organisations of movement dynamics into systems that solve the task at hand. There are now several movement analysis methods designed to search for the signatures of synergies (the uncontrolled manifold, Scholz &amp; Schöner, 1999; tolerance-noise-covariation, Cohen &amp; Sternad, 2009, and others) and a great deal of empirical evidence that synergies feature in movement control. However, while all of these analysis methods rely on notions of ‘task’ to constrain movement solutions, they do not come with a formal theory of what a task is or how tasks are perceived. This paper proposes the hypothesis that tasks should be formalised as task-dynamical affordances, and that perceiving these via specifying information is how they constrain synergy formation (effectivities). I lay out the hypothesis, and detail a research programme to investigate the hypothesis, with reference to existing work on throwing.

There is wide interest in using technologies to enhance the training of sports-specific skills. One promising immersive technology is virtual reality (VR) because it can provide the athlete with rich, immersive, and representative scenarios. The key question is whether training with these systems will transfer to real-world performance. This scoping review examines the existing literature on using VR to improve sports decision-making. We identified 25 papers that used VR (which was very broadly defined by researchers) to train decision-making, and evaluated them with respect to transfer using the Modified Perceptual Training Framework [MPTF: Hadlow et al. (2018). Modified perceptual training in sport: A new classification framework. Journal of Science and Medicine in Sport, 21(9), 950–958]. In general, research is taking advantage of VR’s ability to provide realistic environment, however many papers still rely on simple, non-representative actions from the athletes. Importantly, only six papers assessed transfer of training to real-world behaviour; given that transfer is the purpose of this training, this is a strong limitation on the developing evidence. The existing work does show that VR is worth investigating, so we make a series of recommendations to strengthen future research, with an emphasis on always measuring transfer and doing so guided by ecological approaches such as task dynamics [e.g. Leach, D., Kolokotroni, Z., & Wilson, A. D. (2021a). Perceptual information supports transfer of learning in coordinated rhythmic movement. Psychological Research, 85(3), 1167–1182; Leach, D., Kolokotroni, Z., & Wilson, A. D. (2021b). The ecological task dynamics of learning and transfer in coordinated rhythmic movement. Frontiers in Human Neuroscience, 506] and the MPTF.

The most exciting hypothesis in cognitive science right now is the theory that cognition is embodied. Like all good ideas in cognitive science, however, embodiment immediately came to mean six different things. The most common definitions involve the straight-forward claim that "states of the body modify states of the mind." However, the implications of embodiment are actually much more radical than this. If cognition can span the brain, body, and the environment, then the "states of mind" of disembodied cognitive science won't exist to be modified. Cognition will instead be an extended system assembled from a broad array of resources. Taking embodiment seriously therefore requires both new methods and theory. Here we outline four key steps that research programs should follow in order to fully engage with the implications of embodiment. The first step is to conduct a task analysis, which characterizes from a first person perspective the specific task that a perceiving-acting cognitive agent is faced with. The second step is to identify the task-relevant resources the agent has access to in order to solve the task. These resources can span brain, body, and environment. The third step is to identify how the agent can assemble these resources into a system capable of solving the problem at hand. The last step is to test the agent's performance to confirm that agent is actually using the solution identified in step 3. We explore these steps in more detail with reference to two useful examples (the outfielder problem and the A-not-B error), and introduce how to apply this analysis to the thorny question of language use. Embodied cognition is more than we think it is, and we have the tools we need to realize its full potential.

Previous work has investigated the information-based mechanism for learning and transfer of learning in coordinated rhythmic movements. In those papers, we trained young adults to produce either 90° or 60° and showed in both cases that learning entailed learning to use relative position as information for the relative phase. This variable then supported transfer of learning to untrained coordinations +/30° on either side. In this article, we replicate the 90° study with younger adults and extend it by training older adults (aged between 55 and 65 years). Other work has revealed a steep decline in learning rate around this age, and no follow-up study has been able to successfully train older adults to perform a novel coordination. We used a more intensive training paradigm and showed that while older adult learning rates remain about half that of younger adults, given time they are able to acquire the new coordination. They also learn to use relative position, and consequently show the same pattern of transfer. We discuss implications for attempts to model the process of learning in this task.

© 2017 Cross, Atherton, Wilson and Golonka. Rhythmically coordinating with a partner can increase pro-sociality, but pro-sociality does not appear to change in proportion to coordination success, or particular classes of coordination. Pro-social benefits may have more to do with simply coordinating in a social context than the details of the actual coordination (Cross et al., 2016). This begs the question, how stripped down can a coordination task be and still affect pro-sociality? Would it be sufficient simply to imagine coordinating with others? Imagining a social interaction can lead to many of the same effects as actual interaction (Crisp and Turner, 2009). We report the first experiments to explore whether imagined coordination affects pro-sociality similarly to actual coordination. Across two experiments and over 450 participants, mentally simulated coordination is shown to promote some, but not all, of the pro-social consequences of actual coordination. Imagined coordination significantly increased group cohesion and de-individuation, but did not consistently affect cooperation.

Representations feature heavily in cognitive science theories about our behavioral repertoire. Their critical feature is its ability to designate (stand in for) spatially or temporally distant properties, so that organizing our behavior with respect to mental/neural representations means organizing our behavior with respect to the otherwise unavailable property they designate. Representations are a powerful tool, but serious problems (grounding, system-detectable error) remain unsolved. Ecological explanations reject representations. However, this has left us without a straightforward vocabulary to engage with “representation-hungry” problems involving spatial or temporal distance, nor the role of the nervous system in cognition. To develop such a vocabulary, here we show that ecological information functions to designate the ecologically scaled dynamical world to an organism. We then show that this designation analysis of information leads to an ecological conceptualization of the neural activity caused by information, and finally we argue these together can support intentional behavior with respect to spatially and temporally distal properties. The way they do so (via designation) does mean information and the related neural activity can be conceptualized as representations; but they do so in a grounded way that remains true to key ecological ontological commitments. We advocate this path for expanding the ecological approach.

Moving in time together has been shown to cultivate pro-social effects in co-actors, such as cooperation and helping. But less is known about who these effects apply to - whether they are restricted only to co-actors, or whether they generalize to those not involved in the coordination. One difference between past work finding generalized vs. restricted effects is whether these "outsiders" were present for the coordination or not. The present study explores whether the pro-social effects of coordination are seen towards observers as well as co-actors, and whether the absence or presence of observers during the coordination is a determining factor. Results show that greater cooperation following coordination is only seen amongst co- actors, regardless of whether the observers were present during the task or not. Findings are discussed in the context of the literature and alternative explanations for research showing generalized effects are suggested.

© The Author(s) 2019. In 2010, Bechtel and Abrahamsen defined and described what it means to be a dynamic causal mechanistic explanatory model. They discussed the development of a mechanistic explanation of circadian rhythms as an exemplar of the process and challenged cognitive science to follow this example. This article takes on that challenge. A mechanistic model is one that accurately represents the real parts and operations of the mechanism being studied. These real components must be identified by an empirical programme that decomposes the system at the correct scale and localises the components in space and time. Psychological behaviour emerges from the nature of our real-time interaction with our environments—here we show that the correct scale to guide decomposition is picked out by the ecological perceptual information that enables that interaction. As proof of concept, we show that a simple model of coordinated rhythmic movement, grounded in information, is a genuine dynamical mechanistic explanation of many key coordination phenomena.

In this paper, we trained people to produce 90° mean relative phase using task-appropriate feedback and investigated whether and how that learning transfers to other coordinations. Past work has failed to find transfer of learning to other relative phases, only to symmetry partners (identical coordinations with reversed lead-lag relationships) and to other effector combinations. However, that research has all trained people using transformed visual feedback (visual metronomes, Lissajous feedback) which removes the relative motion information typically used to produce various coordinations (relative direction, relative position; Wilson and Bingham, in Percept Psychophys 70(3):465-476, 2008). Coordination feedback (Wilson et al., in J Exp Psychol Hum Percept Perform 36(6):1508, 2010) preserves that information and we have recently shown that relative position supports transfer of learning between unimanual and bimanual performance of 90° (Snapp-Childs et al., in Exp Brain Res 233(7), 2225-2238, 2015). Here, we ask whether that information can support the production of other relative phases. We found large, asymmetric transfer of learning bimanual 90° to bimanual 60° and 120°, supported by perceptual learning of relative position information at 90°. For learning to transfer, the two tasks must overlap in some critical way; this is additional evidence that this overlap must be informational. We discuss the results in the context of an ecological, task dynamical approach to understanding the nature of perception-action tasks.

Research spanning 100 years has revealed that learning a novel perception-action task is remarkably task-specific. With only a few exceptions, transfer is typically very small, even with seemingly small changes to the task. This fact has remained surprising given previous attempts to formalise the notion of what a task is, which have been dominated by common-sense divisions of tasks into parts. This article lays out an ecologically grounded alternative, ecological task dynamics, which provides us with tools to formally define tasks as experience from the first-person perspective of the learner. We explain this approach using data from a learning and transfer experiment using bimanual coordinated rhythmic movement as the task, and acquiring a novel coordination as the goal of learning. 10 participants were extensively trained to perform 60° mean relative phase; this learning transferred to 30° and 90°, against predictions derived from our previous work. We use recent developments in the formal model of the task to guide interpretation of the learning and transfer results.

Although it is well established that rhythmically coordinating with a social partner can increase cooperation, it is as yet unclear when and why intentional coordination has such effects. We distinguish three dimensions along which explanations might vary. First, pro-social effects might require in-phase synchrony or simply coordination. Second, the effects of rhythmic movements on cooperation might be direct or mediated by an intervening variable. Third, the pro-social effects might occur in proportion to the quality of the coordination, or occur once some threshold amount of coordination has occurred. We report an experiment and two follow-ups which sought to identify which classes of models are required to account for the positive effects of coordinated rhythmic movement on cooperation. Across the studies, we found evidence (1) that coordination, and not just synchrony, can have pro-social consequences (so long as the social nature of the task is perceived), (2) that the effects of intentional coordination are direct, not mediated, and (3) that the degree of the coordination did not predict the degree of cooperation. The fact of inter-personal coordination (moving together in time and in a social context) is all that's required for pro-social effects. We suggest that future research should use the kind of carefully controllable experimental task used here to continue to develop explanations for when and why coordination affects pro-social behaviors.

The most exciting hypothesis in cognitive science right now is the theory that cognition is embodied. Like all good ideas in cognitive science, however, embodiment immediately came to mean six different things. The most common definitions involve the straight-forward claim that “states of the body modify states of the mind.” However, the implications of embodiment are actually much more radical than this. If cognition can span the brain, body, and the environment, then the “states of mind” of disembodied cognitive science won’t exist to be modified. Cognition will instead be an extended system assembled from a broad array of resources. Taking embodiment seriously therefore requires both new methods and theory. Here we outline four key steps that research programs should follow in order to fully engage with the implications of embodiment. The first step is to conduct a task analysis, which characterizes from a first person perspective the specific task that a perceiving-acting cognitive agent is faced with. The second step is to identify the task-relevant resources the agent has access to in order to solve the task. These resources can span brain, body, and environment. The third step is to identify how the agent can assemble these resources into a system capable of solving the problem at hand. The last step is to test the agent’s performance to confirm that agent is actually using the solution identified in step 3. We explore these steps in more detail with reference to two useful examples (the outfielder problem and the A-not-B error), and introduce how to apply this analysis to the thorny question of language use. Embodied cognition is more than we think it is, and we have the tools we need to realize its full potential.

Unlike most other sciences, psychology has no true core theory to guide a coherent research programme. It does have James J Gibson’s ecological approach to visual perception, however, which we suggest should serve as an example of the benefits a good theory brings to psychological research. Here we focus on an example of how the ecological approach has served as a guide to discovery, shaping and constraining a recent hypothesis about how humans perform coordinated rhythmic movements (Bingham 2004a, b). Early experiments on this task were framed in a dynamic pattern approach. This phenomenological, behavioural framework (e.g. Jeka & Kelso 1989) classifies the behaviour of complex action systems in terms of the key order parameters, and describes the dynamical stability of the system as it responds to perturbations. Dynamical systems, however, while a valuable toolkit, is not a theory of behaviour, and this style of research is unable to successfully predict data it is not explicitly designed to fit. More recent work by Bingham & colleagues has used dynamical systems to formalise hypotheses derived from Gibson’s ecological approach to perception and action, with a particular emphasis on perceptual information. The resulting model (Bingham 2001, 2004a, b; Snapp-Childs et al. 2011) has had great success with both the phenomena it was designed to explain as well as a wide range of empirical results from a version of the task it is not specifically designed to explain (specifically, learning a novel coordination). This model and the research programme that produced it stand as an example of the value of theory driven research, and we use it to illustrate the contemporary importance the ecological approach has for psychology.

Movement systems are massively redundant, and there are always multiple movement solutions to any task demand; motor abundance. Movement consequently exhibits ‘repetition without repetition’, where movement outcomes are preserved but the kinematic details of the movement vary across repetitions. The uncontrolled manifold (UCM) concept is one of several methods that analyses movement variability with respect to task goals, to quantify repetition without repetition and test hypotheses about the control architecture producing a given abundant response to a task demand. However, like all these methods, UCM is under-constrained in how it decomposes a task and performance. In this paper, we propose and test a theoretical framework for constraining UCM analysis, specifically the perception of task-dynamical affordances. Participants threw tennis balls to hit a target set at 5m, 10m or 15m, and we performed UCM analysis on the shoulder-elbow-wrist joint angles with respect to variables derived from an affordance analysis of this task as well as more typical biomechanical variables. The affordance-based UCM analysis performed well, although data also showed thrower dynamics (effectivities) need to be accounted for as well. We discuss how the theoretical framework of affordances and affordance-based control can be connected to motor abundance methods in the future.