Preserved perception-action dissociation but altered visuomotor behaviours in healthy aging
Bibliographic record
Abstract
Abstract The two visual pathways hypothesis posits distinct brain systems for vision-for-perception and vision-for-action. While this dissociation is well-established in younger adults, its integrity in healthy aging remains unclear. To address this, younger ( n = 25, range: 18–25 years) and older adults ( n = 25, range: 65–95 years) completed estimation and grasping tasks in two experiments. In Experiment 1, two rectangular objects with varying lengths (40 mm and 42 mm) were placed on the “far” and “close” surfaces of a Ponzo illusion. Despite age-related changes in grasping kinematics, the perception–action dissociation persisted. The Ponzo illusion influenced estimation such that objects placed on the “far” surface were perceived as longer. In contrast, grasping was not affected by the illusion, and even showed effect in the opposite direction, with larger apertures for objects placed on the “close” surface of the illusion. Experiment 2 tested whether this reversed effect was mediated by the surface size on which the object was placed, rather than perceived distance. To this end, we removed the illusory distance cues and varied only the background surface size (“big” versus “small”). While perceptual estimations were unaffected, surface size modulated grasping in both age groups, with a stronger effect in older adults. These findings indicate that the perception–action dissociation is preserved in aging, but older adults rely more on contextual cues during action, potentially reflecting compensatory mechanisms to maintain visuomotor performance.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".