The Effect of Dot Speed and Density on the Maturation of Global Motion Perception
Bibliographic record
Abstract
Global motion stimuli are commonly used to study motion perception, including its development, in human and nonhuman primates. The age at which this aspect of motion perception matures to adult levels is currently a point of contention, with published values ranging from before 3 years of age (Parrish et al., 2005) to after 12 years of age (Lewis et al., 2010). Specific stimulus attributes such as dot speed and density vary considerably across previous studies, which may explain the conflicting results. We measured coherence thresholds for global motion direction discrimination in 5 year-old children and in adults (18–23 years) at two dot speeds (1 and 4 deg/s) and three dot densities (1, 15, 30 dots/deg2). Adult coherence thresholds were constant at approximately 10%, regardless of speed or density. Child coherence thresholds were significantly higher, and were most immature at the slow speed and at the sparsest density. The speed finding confirms previous results (Ellemberg et al., 2004; Hayward et al., 2010). The novel density finding can account for much of the discrepancy in the current developmental literature. These results caution against drawing firm conclusions about visual maturation or deficits in clinical populations based on only a single measurement at a specific combination of speed and density.
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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 | 0.007 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.001 |
| 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".