Adaptive agent modeling of distributed language: investigations on the effects of cultural variation and internal action representations

How do athletes represent actions from their sport? How are these representations structured and which knowledge is shared among experts in the same discipline? To address these questions, the event segmentation task was used. Experts in Taekwondo and novices indicated how they would subjectively split videos of Taekwondo form sequences into meaningful units. In previous research, this procedure was shown to unveil the structure of internal action representations and to be affected by sensorimotor knowledge. Without specific instructions on the grain size of segmentation, experts tended to integrate over longer episodes which resulted in a lower number of single units. Moreover, in accordance with studies in figure-skating and basketball, we expected higher agreement among experts on where to place segmentation marks, i.e., boundaries. In line with this hypothesis, significantly more overlap of boundaries was found within the expert group as compared to the control group. This was observed even though the interindividual differences in the selected grain size were huge and expertise had no systematic influence here. The absence of obvious goals or objects to structure Taekwondo forms underlines the importance of shared expert knowledge. Further, experts might have benefited from sensorimotor skills which allowed to simulate the observed actions more precisely. Both aspects may explain stronger agreement among experts even in unfamiliar Taekwondo forms. These interpretations are descriptively supported by the participants’ statements about features which guided segmentation and by an overlap of the group’s agreed boundaries with those of an experienced referee. The study shows that action segmentation can be used to provide insights into structure and content of action representations specific to experts. The mechanisms underlying shared knowledge among Taekwondoists and among experts in general are discussed on the background of current theoretic frameworks.

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Intact Motor Imagery in Chronic Upper Limb Hemiplegics: Evidence for Activity-Independent Action Representations

Journal of Cognitive Neuroscience ◽

10.1162/089892902760191072 ◽

2002 ◽

Vol 14 (6) ◽

pp. 841-852 ◽

Cited By ~ 102

Author(s):

Scott H. Johnson ◽

Gwen Sprehn ◽

Andrew J. Saykin

Keyword(s):

Motor Imagery ◽

Upper Limb ◽

Full Recovery ◽

Independent Action ◽

Upper Arm ◽

Internal Action ◽

High Level ◽

Vascular Accidents ◽

Experimental Group ◽

Action Representations

Four experiments were undertaken to examine the effects of chronic hemiplegia on the ability to internally represent actions involving either the paralyzed (contralesional) or relatively unaffected (ipsilesional) limb. An experimental group of chronic, densely hemiplegic patients was compared with controls who experienced nearly full recovery from an initially dense hemiparesis. All participants suffered cerebral vascular accidents that spared sites in premotor and parietal areas directly involved in representing upper limb actions. Despite chronic limb immobility, hemiplegic patients performed all four tasks at a high level of accuracy and showed no differences in their ability to represent actions of the contralesional versus ipsilesional limbs. On tasks that involved representing actions of the hands and lower arms, hemiplegic patients were as accurate as recovered controls. Hemiplegic patients were, however, less accurate than controls on a task that involved representing actions of either upper arm. Overall, chronic hemiplegics performed more accurately for decisions based on their contralesional limbs: a “hemiplegic advantage” that may be related to an ongoing focus on planning and/or imagining currently impossible movements. These findings reveal a dissociation between the ability to internally “represent” versus “produce” manual actions. Further, they demonstrate that internal action representations can be robust to even years of limb disuse.

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Comparative investigations of manual action representations: evidence that chimpanzees represent the costs of potential future actions involving tools

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2011.0189 ◽

2012 ◽

Vol 367 (1585) ◽

pp. 48-58 ◽

Cited By ~ 15

Author(s):

Scott H. Frey ◽

Daniel J. Povinelli

Keyword(s):

Tool Use ◽

Cerebral Hemisphere ◽

Food Reward ◽

Task Demands ◽

Limited Attention ◽

Present Moment ◽

Internal Action ◽

Human Cerebellum ◽

Response Alternatives ◽

Action Representations

The ability to adjust one's ongoing actions in the anticipation of forthcoming task demands is considered as strong evidence for the existence of internal action representations. Studies of action selection in tool use reveal that the behaviours that we choose in the present moment differ depending on what we intend to do next . Further, they point to a specialized role for mechanisms within the human cerebellum and dominant left cerebral hemisphere in representing the likely sensory costs of intended future actions. Recently, the question of whether similar mechanisms exist in other primates has received growing, but still limited, attention. Here, we present data that bear on this issue from a species that is a natural user of tools, our nearest living relative, the chimpanzee. In experiment 1, a subset of chimpanzees showed a non-significant tendency for their grip preferences to be affected by anticipation of the demands associated with bringing a tool's baited end to their mouths. In experiment 2, chimpanzees' initial grip preferences were consistently affected by anticipation of the forthcoming movements in a task that involves using a tool to extract a food reward. The partial discrepancy between the results of these two studies is attributed to the ability to accurately represent differences between the motor costs associated with executing the two response alternatives available within each task. These findings suggest that chimpanzees are capable of accurately representing the costs of intended future actions, and using those predictions to select movements in the present even in the context of externally directed tool use.

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