Developmental differences in a coincident timing task under speed and time constraints

The present study examines the effects of speed constraints (target velocity) and time constraints (target duration) on performance on a coincident timing task by 5-, 7- and 9-year-old children and adults. The results showed that the young children significantly improved their performance (per cent of hits) and response accuracy CE, |CE| when given longer time to perform the task. The adults were just as successful for both durations. All subjects showed better performance (per cent of hits) with slower targets, however, for the children this effect was only noticeable with targets of long duration. Target duration also revealed development changes in response control and execution, with the younger children producing different response patterns for IRT, MT and IP measures. The developmental differences at this task are discussed in terms of the control mechanisms involved and the use of strategies in responding.     

Skill transfer specificity shapes perception and action under varying environmental constraints

Using an ecological dynamics framework, this study investigated the generality and specificity of skill transfer processes in organisation of perception and action using climbing as a task vehicle. Fluency of hip trajectory and orientation was assessed using normalized jerk coefficients exhibited by participants as they adapted perception and action under varying environmental constraints. Twelve recreational climbers were divided into two groups: one completing a 10-m high route on an indoor climbing wall; a second undertaking a 10-m high route on an icefall in a top-rope condition. We maintained the same level of difficulty between these two performance environments. An inertial measurement unit was attached each climber’s hips to collect 3D acceleration and 3D orientation data to compute jerk coefficient values. Video footage was used to record the ratio of exploratory/performatory movements. Results showed higher jerk coefficient values and number of exploratory movements for performance on the icefall route, perhaps due to greater functional complexity in perception and action required when climbing icefalls, which involves use of specific tools for anchorage. Findings demonstrated how individuals solve different motor problems, exploiting positive general transfer processes enabling participants to explore the pick-up of information for the perception of affordances specific to icefall climbing.     

Garner interference reveals dependencies between emotional expression and gaze in face perception

The relationship between facial expression and gaze processing was investigated with the Garner selective attention paradigm. In Experiment 1, participants performed expression judgments without interference from gaze, but expression interfered with gaze judgments. Experiment 2 replicated these results across different emotions. In both experiments, expression judgments occurred faster than gaze judgments, suggesting that expression was processed before gaze could interfere. In Experiments 3 and 4, the difficulty of the emotion discrimination was increased in two different ways. In both cases, gaze interfered with emotion judgments and vice versa. Furthermore, increasing the difficulty of the emotion discrimination resulted in gaze and expression interactions. Results indicate that expression and gaze interactions are modulated by discriminability. Whereas expression generally interferes with gaze judgments, gaze direction modulates expression processing only when facial emotion is difficult to discriminate.     

Searching for the minimal essential information for skilled perception and action

Summary A common concern for both cognitive/computational and ecological/dynamical models of human motor control is the isolation of the minimal essential information needed to support skilled perception and action. In perception isolating essential features of the optic flow field, which are reliably informative regarding the nature of current events, from nonessential features provides a valuable step towards understanding how the computational complexity of perceptual information processing may be reduced to manageable levels and how relatively direct linkages of low dimensionality may be established between information and control variables. Likewise, in the study of action, discrimination of the movement features that remain immutable (invariant?) across changes in task conditions from the variables that are situationally determined provides a principled insight into the structural framework upon which skilled movement is built. Controversy abounds, however, in the study of perception and action as to whether features isolated as informative and immutable are centrally represented (in the form of a template or program) or are rather directly picked up (in the case of perceptual variables) or are simply an emergent consequence of the underlying dynamics (in the case of action variables). In this paper some examples of putative minimal essential information sources in perception and action are provided, strategies for uncovering such sources are discussed, and attention is directed, with the use of some recent data collected on natural skills, to some systematic expert-novice differences in the utilization of essential information and control variables. Expert-novice differences are highlighted because of the insight they may provide regarding the nature of perceptual-motor skill acquisition.     

Efficient search under constraints and not working memory resources supports creative action emergence in a convergent motor task

Creative (original and functional) solutions to problems can be facilitated by guiding search behavior. According to cognitive models, when solving convergent tasks (tasks with few solutions), high available working memory (WM) resources and capacity can guide creative solution emergence via repeated (persistent) search within a solution subcategory. However, no clear associations have been found of WM capacity on creative outcomes when tasks require the individual to enact solutions in divergent doing tasks. This study further tested constraints on WM resources on search behavior and creative outcomes in a convergent doing task. Novices to combat sports were asked to repeatedly strike a target with the intent to achieve an individualized target force. In order to manipulate available WM resources, every ten strikes, participants were asked to recall and then retain a sequence of 5 digits (high load group: n = 21) or 2 digits (low load group: n = 21). The task constraints favored the functionality (or appropriateness) of a qualitatively distinct, non-obvious solution. Functionality was assessed using the force registered for each strike. Originality was assessed in terms of how infrequently actions occurred. Finally, search behavior was quantified based on changes in which limb was used and changes in which part of the limb was used from one strike to the next. There were no significant effects of WM load on creativity outcomes, solution search, or task success. Rather, task success was related to efficient search and creativity. Future research should focus on constraints (other than WM resources) that promote efficient search.     

Effects of visual information and task constraints on intersegmental coordination in playground swinging

The authors investigated how and to what extent visual information and associated task constraints are negotiated in the coordinative structure of playground swinging. Participants (N = 20) were invited to pump a swing from rest to a prescribed maximal amplitude under 4 conditions: normal vision, no vision, and 2 visual conditions involving explicit phasing constraints. In the latter conditions, participants were presented with a flow pattern consisting of a periodically expanding and contracting optical structure. They were instructed to phase the swing motion so that the forward turning point coincided with either the maximal size (enhanced optical flow) or the minimal size (reduced optical flow) of the presented flow pattern. Removal of visual information clearly influenced the swinging behavior, in that intersegmental coordination became more stereotyped, reflecting a general stiffening of the swinger. The conditions involving explicit phasing requirements also affected the coordination, but in an opposite way: The coordination became less stereotyped. The two phasing instructions had differential effects: The intersegmental coordination deviated more from normal swinging (i.e., without phasing constraints) when optical flow was enhanced than when it was reduced. Collectively, those findings show that visual information plays a formative role in the coordinative structure of swinging, in that variations of visual information and task constraints were accompanied by subtle yet noticeable changes in intersegmental coordination.     

Dynamic object perception by pigeons: discrimination of action in video presentations

Two experiments examined the discrimination by pigeons of relative motion using computer-generated video stimuli. Using a go/no-go procedure, pigeons were tested with video stimuli in which the camera's perspective went either "around" or "through" an approaching object in a semi-realistic context. Experiment 1 found that pigeons could learn this discrimination and transfer it to videos composed from novel objects. Experiment 2 found that the order of the video's frames was critical to the discrimination of the videos. We hypothesize that the pigeons perceived a three-dimensional representation of the objects and the camera's relative motion and used this as the primary basis for discrimination. It is proposed that the pigeons might be able to form generalized natural categories for the different kinds of motions portrayed in the videos. Accepted after revision: 23 March 2001 Electronic Publication     

Authorship effects in the prediction of handwriting strokes: Evidence for action simulation during action perception

Does the action system contribute to action perception? Recent evidence suggests that actions are simulated while being observed. Given that the planning and simulating system are the same only when one observes one's own actions, it might be easier to predict the future outcomes of actions when one has carried them out oneself earlier on. In order to test this hypothesis, three experiments were conducted in which participants observed parts of earlier self- and other-produced trajectories and judged whether another stroke would follow or not. When the trajectories were produced without constraints, participants accomplished this task only for self-produced trajectories. When the trajectories were produced under narrow constraints, the predictions were equally accurate for self- and for other-generated trajectories. These results support the action simulation assumption. The more the actions that one observes resemble the way one would carry them out oneself, the more accurate the simulation.     

Interactions between perception and action in a reaction task with overlapping S-R assignments

 We have used a novel task to study relationships between perception and action. Four experiments studied stimulus-response (S-R) relationships under conditions in which stimuli and responses were functionally unrelated (i.e., not assigned to each other by instruction) and merely overlapped in time. On each trial, participants carried out movements on a graphic tablet while observing motions displayed on a computer screen. The movement on trial n was specified by the motion observed on the previous trial n-1, whereas the motion observed on trial n specified the movement to be performed on trial n+1. Results showed that stimulus motion had a contrast-like impact on response movement. Watching a small motion while performing a medium-sized movement increased movement size, whereas watching a large motion led to a decrease (Experiment 1). Further experiments showed that the contrast pattern was not affected by the mode of motion presentation (Experiment 2), or by the interval between motion and movement execution (Experiment 3). Contrast was also observed in the reverse direction, i.e., from action to perception (Experiment 4). We propose that the contrast effect is due to a mechanism for selective code modification. This mechanism acts to increase the distinctiveness of simultaneously activated perception and action codes in a common representational domain. Received: 11 July 2000 / Accepted: 4 March 2001     

The role of video in facilitating perception and action of a novel coordination movement

Two groups (n = 10 in each) practiced a novel, bimanual coordination pattern that was demonstrated on video. One of the groups received augmented video feedback of their own responses after each trial following a demonstration. The video-feedback group showed better performance in acquisition and retention than the no-feedback group. On error-detection tests, the video-feedback group was better able to distinguish between correct and incorrect movement patterns. The authors concluded that video feedback helps to make relative phase information salient by aiding the discrimination process. Prepractice ability on a scanning task revealed that individuals who persevered with in-phase-type movements, even though the task demands dictated otherwise, had the most difficulty determining and subsequently performing the required movement. Video feedback helped them to compensate for those difficulties.     

No transfer of calibration between action and perception in learning a golf putting task

We assessed calibration of perception and action in the context of a golf putting task. Previous research has shown that right-handed novice golfers make rightward errors both in the perception of the perfect aiming line from the ball to the hole and in the putting action. Right-handed experts, however, produce accurate putting actions but tend to make leftward errors in perception. In two experiments, we examined whether these skill-related differences in directional error reflect transfer of calibration from action to perception. In the main experiment, three groups of right-handed novice participants followed a pretest, practice, posttest, retention test design. During the tests, directional error for the putting action and the perception of the perfect aiming line were determined. During practice, participants were provided only with verbal outcome feedback about directional error; one group trained perception and the second trained action, whereas the third group did not practice. Practice led to a relatively permanent annihilation of directional error, but these improvements in accuracy were specific to the trained task. Hence, no transfer of calibration occurred between perception and action. The findings are discussed within the two-visual-system model for perception and action, and implications for perceptual learning in action are raised.     

A novel variation of the Stroop task reveals reflexive supremacy of peripheral over gaze stimuli in pro and anti saccades

A long-standing controversy in social attention debates whether gaze-of-another induces reflexive shifts of one’s own attention. In attempting to resolve this controversy, we utilized a novel Stroop task, the PAT Stroop, in which pro- and anti-saccade (PAT) responses are made to competing gaze and peripheral stimuli. The first experiment demonstrated a “Stroop effect” for peripheral stimuli, i.e. peripheral distractors interfered with gaze triggers, but gaze distractors did not interfere with peripheral triggers. These results were replicated in the second experiment, which also negated the possibility that the mere display and practice of the “clean PAT” influenced the results. Thus, the use a new PAT Stroop task demonstrated reflexive supremacy of peripheral stimuli over gaze stimuli. This novel variant of the Stroop task demonstrated similar characteristics to the classic color naming Stroop - i.e. an asymmetrical pattern, and again showed the utility and versatility of stoop-like tasks in probing mental tasks.     

Coordinating cognitive information: task effects and individual differences in integrating information from several sources.

In many tasks people have to coordinate the information from several sources. An example would be driving a car while listening to directions. The driver has to establish a correspondence between a visual picture and verbal instructions. This paper addresses two questions concerning information coordination. Is there an ability to coordinate information received from several sources that is different from the ability to deal with information from each source, alone? Does coordination simply involve allocating resources to deal with the component tasks, or does the act of coordination itself constitute a separate task? Four experiments examined the coordination of a verbal component task with a visual-spatial and with an auditory component task. The results showed that the ability to coordinate perceptual and verbal information is separate from the ability to deal with either perceptual or verbal information, alone. A simple resource sharing model was not adequate in explaining how coordination occurred. We relate our results to a model in which perceptual reasoning occurs independently of verbal processing, but transforming perceptual information into a propositional form is affected by concurrent verbal processing.     

Visual experience enhances infants' use of task-relevant information in an action task

Four experiments examined whether infants' use of task-relevant information in an action task could be facilitated by visual experience in the laboratory. Twelve- but not 9-month-old infants spontaneously used height information and chose an appropriate (taller) cover in search of a hidden tall toy. After watching examples of covering events in a teaching session, 9-month-old infants succeeded in an action task that involved the same event category; learning was not generalized to events from a different category. The present results demonstrate that learning through visual experience can be transferred to infants' subsequent actions. These findings shed light on the link between perception and action in infancy.     

The positive and negative of human expertise in gaze perception

Judging where others look is crucial for many social and cognitive functions. Past accounts of gaze perception emphasize geometrical cues from the seen eye. Human eyes have a unique morphology, with a large white surround (sclera) to the dark iris that may have evolved to enhance gaze processing. Here we show that the contrast polarity of seen eyes has a powerful influence on gaze perception. Adult observers are highly inaccurate in judging gaze direction for images of human eyes with negative contrast polarity (regardless of whether the surrounding face is positive or negative), even though negative images of eyes preserve the geometric properties of positives that are judged accurately. The detrimental effect of negative contrast polarity is much larger for gaze perception than for other directional judgements (e.g. judging which way a head is turned). These results suggest an 'expert' system for gaze perception, which always treats the darker region of a seen eye as the part that does the looking.     

Examining age differences in performance of a complex information search and retrieval task.

This study examined age differences in performance of a complex information search and retrieval task by using a simulated real-world task typical of those performed by customer service representatives. The study also investigated the influence of task experience and the relationships between cognitive abilities and task performance. One hundred seventeen participants from 3 age groups, younger (20-39 years). middle-aged (40-59 years), and older (60-75 years), performed the task for 3 days. Significant age differences were found for all measures of task performance with the exception of navigational efficiency and number of problems correctly navigated per attempt. There were also effects of task experience. The findings also indicated significant direct and indirect relations between component cognitive abilities and task performance.     

Age-related differences in the visual processes implied in perception and action: distance and location parameters

The aim of the two present experiments was to examine the ontogenetic development of the dissociation between perception and action in children using the Duncker illusion. In this illusion, a moving background alters the perceived direction of target motion. Targets were held stationary while appearing to move in an induced displacement. In Experiment 1, 30 children aged 7, 9, and 12 years and 10 adults made a perceptual judgment or pointed as accurately as possible, with their index finger, to the last position of the target. The 7-year-old children were more perceptually deceived than the others by the Duncker illusion but there were no differences for the goal-directed pointing movements. In Experiment 2, 50 children aged 7, 8, 9, 10, and 11 years made a perceptual judgment or reproduced as accurately as possible, with a handle, the distance traveled by the target. Participants were perceptually deceived by the illusion, judging the target as moving although it was stationary. When reproducing the distance covered by the target, children were unaffected by the Duncker illusion. Our results suggest that the separation of the allocentric visual perception pathway from the egocentric action pathway occurs before 7 years of age.     

Developmental differences in the use of visual information during a continuous bimanual coordination task

The authors examined the influence of different amounts of visual information when children 4 (CH4), 6 (CH6), and 8 (CH8) years of age, and adults (n = 12 in each group) performed a steady-state bimanual circle-drawing coordination task at self-selected speeds. All participants maintained in-phase coordination, but different strategies for maintaining the pattern emerged. A predictable relationship between variability and age was not observed, in that the CH8 group was not necessarily more consistent than the CH6 and CH4 groups. The authors conclude that children are transitioning from dependence on kinesthetic feedback to reliance on visual feedback around age 8, as suggested by L. Hay, C. Bard, M. Fleury, and N. Teasdale (1991; L. Hay, M. Fleury, C. Bard, & N. Teasdale, 1994; L. Hay & C. Redon, 1997), and that future studies are needed to further explore visual and kinesthetic feedback as potential control parameters during coordination tasks in developing children.