Temporal asynchrony in contour integration: A retelling of the fable of "The Hare and the Tortoise"
Bibliographic record
Abstract
PURPOSE. Evidence that visual grouping is facilitated when elements comprising a foreground figure are presented simultaneously, and are temporally separated from elements comprising the background, has suggested cortical synchronous oscillations as a possible neural substrate. Supporting this theory, Usher & Donnelly (Nature, 1998) showed that contour integration is facilitated when path and background elements alternate with an asynchrony below the integration time of the visual system, suggesting that these flickering stimuli interact with this hypothetical binding mechanism. We investigated this puzzling result using a standard contour integration paradigm (Field et al, Vis. Res., 1993). METHODS. The task required the linking of orientation across space to detect a path in a stimulus composed of randomly oriented Gabor elements (1.5 cpd, sigma = 0.17 deg), measured using a temporal 2AFC method. In a first experiment, we explored the effect of onset delays between path and background elements. In a second experiment, we replicated Usher & Donnelly's experiment with a cyclic presentation and controlled for stimulus order. RESULTS. The first experiment demonstrated a strong priming effect of path elements. The second experiment demonstrated that the effect reported by Usher & Donnelly depends, in fact, on the order of asynchrony between path and background elements in the first cycle of the stimuli presentation: facilitation in visual grouping only occurred when path elements were presented before background elements. CONCLUSIONS. We conclude that Usher & Donnelly's result is likely due to the high sensitivity of the visual system to stimulus onset, and that simple flickering stimuli are inadequate for revealing the neural code for binding in figure-ground segregation.
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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 | 0.002 | 0.008 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.006 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| 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".