Does perspective-distortion modulate the temporal tuning of symmetry responses?
Bibliographic record
Abstract
Symmetry is a highly salient feature in both natural and man-made environments. Numerous species are sensitive to symmetry, and symmetry is thought to be an important cue for visual tasks, including viewpoint-invariant representation of objects, detection of regularity and structure, and mate selection. However, although symmetries are common in natural and artificial objects and scenes, they are subject to perspective-distortion and thus rarely give rise to symmetrical patterns on the retina during natural vision. Here, we build on previous studies showing that perspective-distortion makes symmetry responses weaker and more task-dependent (Makin et al., 2014; Keefe et al., 2018) by investigating the effect of perspective-distortion on the temporal tuning of symmetry responses. We used novel, naturalistic 3D objects that had reflection symmetry over a vertical axis. The objects were procedurally generated along with well-matched control objects without any symmetries and then rendered to produce images in which object symmetries are either present in the image-plane or perspective-distorted. We measured visual system responses to image-plane and perspective-distorted symmetry using high-density EEG with a Steady-State Visual Evoked Potentials (SSVEPs) paradigm in which images of symmetrical objects alternate with images of control objects. This makes it possible to isolate symmetry-specific brain activity in the odd harmonics of the stimulation frequency. To investigate the temporal tuning of these responses, we used seven different stimulation frequencies in different conditions, between 1 and 10 Hz. We collected data from 30 participants with normal or corrected-to-normal visual acuity. We found that for both image-plane and perspective-distorted symmetry, responses peak at 2 Hz and are much reduced at higher frequencies across electrodes over occipital and temporal cortex. Response amplitudes were generally higher for image-plane symmetry, but surprisingly, the spatial tuning was not strongly modulated by perspective-distortion. Further investigations will determine how distinct visual regions may contribute to these results.
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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 | 0.000 | 0.002 |
| 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".