Why is the tilt after-effect selective to local but not global luminance-contrast polarity?
Bibliographic record
Abstract
Aim: Prolonged exposure to an oriented line oppositely shifts the perceived orientation of a subsequently observed line, a phenomenon known as the tilt aftereffect (or TAE). The TAE transfers across luminance contrast polarity (Magnussen & Kurtenbach, 1979, Perception 8(5), 523-528), suggesting that either the polarities of local detectors are discarded before combining to encode the global orientation of the line, or that polarity is discarded after the global orientation of the line is encoded. Here we test between these two alternatives. Methods: The TAE was measured using line stimuli constructed from strings of ‘dark’ or ‘white’ elongated Gaussian micropatterns. Adaptors were either all white, all dark, one-alternating or two-alternating polarities. Test lines were either all white or one-alternating polarity. Results: (i) TAEs with all-white tests were small with one-alternating polarity adaptors, increased slightly for two-alternating polarity adaptors, and were largest with all-white or all-black adaptors. (ii) TAEs were also large when the test was one-alternating, irrespective of the adaptor type. Conclusion: The fact that alternating polarity adaptors produced only weak TAEs in all-white tests supports the idea that for 1st-order line orientation mechanisms polarity is discarded only after global line orientation is encoded. However the existence of strong TAEs for alternating polarity tests suggests that alternating polarities are combined by 2nd-order line orientation mechanisms. The asymmetry in the magnitude of TAE between alternating-polarity adaptors with white tests, and white adaptors with alternating-polarity tests, can be explained by an imbalance in the population of neurons sensitive to 1st- and 2nd-order stimuli, in that the 2nd-order stimuli are encoded by a subset of the mechanisms sensitive to 1st-order stimuli. The similar size TAE obtained with white adaptor/test and alternating polarity adaptor/test suggests that there are no neurons exclusively sensitive to 2nd-order stimuli. Meeting abstract presented at VSS 2013
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".