Testing the limits of temporal phase perception of isoluminant color modulation
Bibliographic record
Abstract
Introduction: Temporal phase perception, which involves comparing modulations between temporal stimuli, is significantly slower than peripheral stimulus detection, suggesting a central temporal bottleneck. While phase perception thresholds for luminance flicker (7–10 Hz) have been studied, those for chromatic flicker remain largely unexplored. The critical flicker fusion frequency (CFF) for chromatic flicker (~30 Hz) is about half that of luminance flicker (~60 Hz), reflecting slower mechanisms in chromatic processing. It remains unclear whether this slower peripheral processing plays a greater role in central phase comparisons or if a general central temporal bottleneck, independent of peripheral stimulus characteristics, has a greater impact. To investigate, we measured phase discrimination thresholds for chromatic modulations across a range of temporal frequencies (TFs). Methods: Phase discrimination thresholds were measured using two chromatic circles rotating through isoluminant hue space (0–360° in HSV color space). Isoluminence was determined for R, G, and B channels using flicker photometry, and the isoluminant HSV values were calculated. Thresholds were measured across seven TFs (1–20 Hz) under two distance conditions (3° and 12°). Stimuli were displayed using a 480 Hz VPixx PROPixx projector at 4° eccentricity, with the circles positioned to the left and right of the screen center. Participants adjusted the test chromatic flicker’s TF and phase to match a reference flicker. Results: Phase error magnitude increased with TF under both distance conditions, indicating greater difficulty in phase discrimination at higher frequencies, particularly at 3–5 Hz and above. Phase error was generally lower in the near condition compared to the far condition. Conclusion: Our findings show that phase perception for chromatic modulations operates at a temporal scale slower than phase comparisons in luminance modulations, challenging the idea of a constant central temporal bottleneck. Instead, this suggests that the temporal limitations of peripheral stimuli play an important role for central phase comparisons.
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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 | 0.005 |
| 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".