Reduced sensitivity to size but preserved perception-action dissociation in older adults.
Bibliographic record
Abstract
According to the two visual pathways hypothesis, vision-for-perception and vision-for-action are mediated by different neural pathways. While this dissociation has been well-studied in younger adults using psychophysics and neuroimaging, it is unclear whether healthy aging modulates the dissociation across the lifespan. To bridge this gap, we examined the effect of aging on visuomotor and perceptual tasks in two experiments, both completed by older (n = 26, range: 60–95 years) and younger adults (n = 26, range: 18–25 years). Experiment 1 aimed to test for potential differences among perceptual and visuomotor sensitivity to object size using “Efron blocks”, which vary in width and length but have an identical surface area. In the two conditions, participants were asked to perceptually estimate the width of the blocks using their fingers or to grasp the objects across their width. Experiment 2 utilized the Ponzo illusion to explore potential differences in the dissociation between perception and visuomotor control between younger and older adults. Participants completed the perceptual and grasping conditions with objects placed on the “close” and “far” surfaces of the illusion. The results of Experiment 1 showed an age-related decrement in size sensitivity, which was more strongly evident in the grasping task. In Experiment 2, both groups demonstrated a dissociation between perception and action, such that greater perceptual estimations were observed when objects were placed on the “far” surface of the illusion, while this effect was not observed during the grasping task. Unexpectedly, older adults even exhibited a reversed effect during grasping, with larger apertures for objects placed on the “close” surface. These findings suggest that while visuomotor abilities decline with age, the dissociation between perception and action is largely preserved.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 teacher head, 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".