The contribution of the reach and the grasp to shaping brain and behaviour.
Bibliographic record
Abstract
Skilled hand use is a striking feature of human behaviour, but in contrast to the view that it recently evolved in the primate lineage, the present paper argues that skilled hand movements have an early phylogenetic origin dating back to the synergies displayed by the pectoral fins of bony fishes. Insights into the function and evolution of hand use stem from the dual visuomotor channel theory, which proposes that prehension is a composite of 2 movements, the reach and the grasp. The reach is in part an egocentric act directed toward the extrinsic (location) features of objects while the grasp is in part an allocentric act directed toward the intrinsic (shape and size) features of objects. Phylogenetic, developmental, and behavioural evidence suggest that the reach and the grasp evolved separately under somatosensory control and were subsequently coordinated with visual control in the primate lineage. Accordingly, parallel pathways from visual cortex came to influence separate reach and grasp systems in parietofrontal cortex, and new descending pathways to the spinal cord came to assist in visually guided reaching. Neural processes related to the "where" of the reach and the "what" of the grasp have had a formative role in shaping cognition more generally.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.003 | 0.003 |
| Science and technology studies | 0.000 | 0.003 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
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".