Aging reduces surround suppression effects in a perceived speed task
Bibliographic record
Abstract
In younger adults, direction discrimination for high-contrast patterns becomes more difficult as stimulus size increases (Tadin et al., Nature, 2003, 424, 312-5). Betts et al. (Neuron, 2005, 45, 361-6) found that this effect, known a spatial suppression, is reduced significantly in older adults, and hypothesized that this behavioural finding occurred as a result of decreased GABAergic inhibition in the aging visual system (Leventhal et al., Science, 2003, 300, 812-15). Recently, van der Smagt et al. (Vision Res., 2010, 50, 1900-4) found evidence for spatial suppression in younger adults using a task that measured the perceived speed, rather than the direction, of drifting gratings: perceived speed increased with stimulus size at low contrast, but decreased with increasing size at high contrast. The current experiment examined whether the effects of spatial suppression on speed judgments are reduced in older adults. Nine younger and 11 older subjects compared the speed of a drifting 1 cpd reference grating that varied in size (0.7 & 5 deg diameter) and contrast (2.8 & 92%) across conditions to the speed of a 1 cpd test grating that drifted at 2 deg/sec and whose size (0.7 deg) and contrast (38%) were fixed. Results from younger subjects replicated the main findings reported by van der Smagt et al., but the effect of stimulus size at high contrast was significantly smaller in older subjects. These results are consistent with the hypothesis that aging diminishes the effects of spatial suppression on motion tasks, although suppression may not change for tasks using static stimuli (Karas & McKendrick, J Vis, 2009, 9(5):11, 1-9; Farber et al., VSS 2010 & 2011) . Meeting abstract presented at VSS 2012
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 | 0.000 | 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) | 0.002 | 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".