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Sara M. Scharoun, Pamela J. Bryden, Michael E. Cinelli, David A. Gonzalez and Eric A. Roy

This study investigated whether 5- to 11-year-old children perceive affordances in the same way as adults (M age = 22.93, SD = 2.16) when presented with a task and four tools (nail in a block of wood and a hammer, rock, wrench, and comb; bucket of sand and a shovel, wooden block, rake, and tweezers; and a screw in a block of wood and a screwdriver, knife, dime, and crayon). Participants were asked to select the best tool and act on an object until all four assigned tools had been selected. No explicit instructions were provided because we were interested in how task perception would influence tool selection and action. Results support the notion that the capacity to perceive affordances increases with age. Furthermore, differences in the way in which 5-year-olds acted on the screw in a block of wood demonstrated that the ability to detect some affordances takes longer to refine. Findings help to further the understanding of the development of perception-action coupling.

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Geert J.P. Savelsbergh, John van der Kamp and Walter E. Davis

Twenty-one children with Down syndrome (DS) and 20 without disability, ages 3 to 11 years, completed the experiment in which they were asked to grasp and lift cardboard cubes of different sizes (2.2 to 16.2 cm in width). Three conditions were used: (a) increasing the size from the smallest to the largest cube, (b) decreasing the size from the largest to the smallest, and (c) a random order of sizes. Children with DS were found to have smaller hand sizes in comparison to age-matched children without DS. In addition, the shift from one-handed to two-handed grasping appeared at a smaller cube size for children with DS than for children without DS. However, when the dimensionless ratio between object size and hand size was considered, the differences between groups disappeared, indicating that the differences in grasping patterns between children with and without DS can be attributed to differences in body size.

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Georgios T. Angelakopoulos, Haralambos Tsorbatzoudis and George Grouios

In many dynamic interceptive actions performers need to integrate activity of manual and postural subsystems for successful performance. Groups of different skill level (poor and good catchers), (mean age = 9.1 and 9.4 respectively) were required to perform one-handed catches under different postural constraints: standing; standing in contact with a postural support aid by their side (PSAS) or to the left of their trunk (PSAF); Tandem; and sitting (control). Results revealed that, for poor catchers, the number of successful catches increased and grasp errors decreased significantly when sitting and with both postural aids in comparison with standing alone and Tandem conditions. Kinematic analyses showed that the postural aid devices reduced head sway in the anterior-posterior direction, while the PSAF reduced lateral head sway. The poor catchers’ performance benefited from an enlarged support surface, and reduction of lateral sway. Good catchers performed successfully under all task constraints, signifying the existence of a functional relationship between postural and grasping subsystems during performance. The results are discussed in the frame of Bernstein’s (1967) and Newell’s (1986) theory.

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Paula F. Polastri and and José A. Barela

This study examined the effects of experience and practice on the coupling between visual information and trunk sway in infants with Down syndrome (DS). Five experienced and five novice sitters were exposed to a moving room, which was oscillated at 0.2 and 0.5 Hz. Infants remained in a sitting position and data were collected on the first, fourth, and seventh days. On the first day, experienced sitters were more influenced by room oscillation than were novices. On the following days, however, the influence of room oscillation decreased for experienced but increased for novice sitters. These results suggest that the relationship between sensory information and motor action in infants with DS can be changed with experience and practice.

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Ana M. F. Barela, José A. Barela, Natália M. Rinaldi and Diana R. de Toledo

This study examined the influence of both optic flow characteristics and intention on postural control responses. Two groups of 10 adults each were exposed to the room’s movement either at 0.6 cm/s (low velocity group) or 1.0 cm/s (high velocity group). All the participants stood in the upright stance inside of a moving room and were informed about the room movement only after the fourth trial as they were asked to resist to its influence. Results revealed that participants from both groups were influenced by the imposed visual stimulus in the first trials, but the coupling strength was weaker for the high velocity group. The request to resist the visual influences decreased visual influences on body sway, but only for the low velocity group. These results indicate that intention might play a role in stimulus influences on body sway but it is stimulus dependent.

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Thomas A. Stoffregen, M. Russell Giveans, Sebastien Villard, Jane Redfield Yank and Kevin Shockley

When two standing people converse with each other there is an increase in their shared postural activity, relative to conversation with different partners. We asked pairs of participants to converse with each other or with experimental confederates while standing on rigid and nonrigid surfaces. On the rigid surface, shared postural activity was greater when participants conversed with each other than when they conversed with confederates. In addition, the strength of interpersonal coupling increased across trials, but only when members of a dyad conversed with each other. On the nonrigid surface, postural sway variability increased, but we found no evidence that shared postural activity was different when participants conversed with each other, as opposed to conversing with confederates. We consider several possible interpretations of these results.

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Nicholas E. Fears and Jeffrey J. Lockman

perception–action approach for understanding handwriting development. First, we review two traditional approaches to handwriting research that are used in the education and motor control literatures. Then, we outline a perception–action approach for studying handwriting development, focusing on the ongoing

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Jason C. Laffer, Aaron J. Coutts and Job Fransen

execute an accurate and fast blocking movement, especially at higher levels of competition where faster gameplay creates greater time constraints ( Panfil & Superlak, 2012 ). Successful decision-making when blocking requires exceptional levels of two performance elements, perception–action coupling and

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Benoît Lenzen, Catherine Theunissen and Marc Cloes

This exploratory study aimed to investigate elements involved in decision making in team handball live situations and to provide coaches and educators with teaching recommendations. The study was positioned within the framework of the situated action paradigm of which two aspects were of particular interest for this project: (a) the relationship between planning and action, and (b) the perception-action coordination. We used qualitative methods that linked (a) video observation of six female elite players’ actions during two championship matches and (b) self-confrontation interviews. Players’ verbalizations reflected that their decision making included the following: (a) perception (visual, auditory, tactile, proprioceptive), (b) knowledge (concepts, teammates and opponents’ characteristics, experience), (c) expectations (opponents and teammates’ intentions), and (d) contextual elements (score, power play, players on the field, match difficulty). Findings were discussed in terms of teaching implications.

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Markus Janczyk and Wilfried Kunde

According to the Perception-Action-Model (PAM), the human visual cortex consists of the ventral vision-for-perception and the dorsal vision-for-action streams. Performance decrements with increasing variation of nominally task-irrelevant stimulus features (Garner-Interference) was suggested as an empirical tool for identifying contributions of these streams: vision-for-perception, but not visionfor-action, should suffer from Garner-Interference, but inconsistencies in this argument were revealed by several studies. We here used a new manipulation to induce Garner-Interference in a dorsal task: The stimulus objects did not differ in their lengths but in the side to which they were weighted. In Experiment 1, Garner-Interference was found in a ventral perceptual judgment task. Notably, we did also find Garner-Interference in skilled right-handed grasping in Experiment 2. These findings suggest that the presence or absence of Garner-Interference does not consistently index the contribution of different processing streams for perception and action, but the coprocessing of nominally task-irrelevant stimulus features in general, be it for perception of action.