Reach and Grasp Altered in Pantomime String-Pulling: A Test of the Action/Perception Theory in a Bilateral Reaching Task
Bibliographic record
Abstract
Abstract The action/perception theory of cortical organization is supported by the finding that pantomime hand movements of reaching and grasping are different from real movements. Frame-by-frame video analysis and MATLAB ® based tracking examined real/pantomime differences in a bilaterally movement, string-pulling, pulling down a rope with hand-over-hand movements. Sensory control of string-pulling varied from visually-direct when cued, visually-indirect when non cued and somatosensory controlled in the absence of vision. Cued grasping points were visual tracked and the pupils dilated in anticipation of the grasp, but when noncued, visual tracking and pupil responses were absent. In real string-pulling, grasping and releasing the string featured an arpeggio movement in which the fingers close and open in the sequence 5 through 1 (pinki first, thumb last); in pantomime, finger order was reversed, 1 through 5. In real string-pulling, the hand is fully opened and closed to grasp and release; in pantomime, hand opening was attenuated and featured a gradual opening centered on the grasp. The temporal structure of arm movements in real string-pulling featured up-arm movements that were faster than down-arm movement. In pantomime, up/down movements had similar speed. In real string-pulling, up/down arm movements were direct and symmetric; in pantomime, they were more circular and asymmetric. That pantomime string-pulling featured less motoric and temporal complexity than real string-pulling is discussed in relation to the action/perception theory and in relation to the idea that pantomimed string-pulling may feature the substitution of gestures for real movement. Significant Statement Most laboratory studies investigating hand movements made by humans feature single hand movements, the current study presents a novel string-pulling task to study bimanual coordination of left and right hands in real and pantomime conditions. The results show that pantomime string-pulling featured less motoric and temporal complexity than real string-pulling. These findings are relevant to the contemporary theory of action and perception that the dorsal stream (parietal cortex) is related to actions and the ventral stream (temporal cortex) is related to perception.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.007 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".