Motion Coherence Discrimination (Random-Dot Kinematogram)
A cloud of moving dots is shown; a fraction of them — the coherence — drifts coherently in one direction (left or right) while the rest move at random, and the observer reports the net direction. Coherence is the CONTINUOUS independent variable, varied trial to trial; direction-discrimination accuracy rises with it, tracing a psychometric function. The primary measure is not an accuracy or a difference of cell means but a THRESHOLD — the coherence at a criterion accuracy (~75% for two-alternative forced choice) — recovered by fitting the psychometric function to the (coherence, correct) data. This is the catalog's first continuous-level paradigm: the threshold is a fitted point in stimulus units, and it is undefined unless the tested levels bracket it and performance is not flat.
- Defining contrast
coherence-threshold (psychometric)- Family
- psychophysics
- Human review
- sourced — unreviewed
- Executable test
- verify:task — an implementation can be driven and judged against this spec
- Schema
- spec version 9
Where this spec stands
This record is sourced. The ladder below is the human-review axis
only — a passing executable test never moves a record up it.
sourcedLiterature-linked, drafted with LLM assistance or by a contributor, and unreviewed. The honest default.corroboratedIndependently cross-checked against the cited sources, but not signed by a named expert.expert-annotatedAll three claims attested by named experts. Derived, never self-declared.contestedA named expert disputes at least one claim. A real outcome, kept visible.
Origin reference
- Newsome, W. T., & Paré, E. B. (1988). A selective impairment of motion perception following lesions of the middle temporal visual area (MT). The Journal of Neuroscience, 8(6), 2201-2211. doi:10.1523/jneurosci.08-06-02201.1988
Review this specification
Three separable claims: does the contrast identify the paradigm, is it a defensible measure of the named construct, and are the psychometric numbers correctly conditioned? Attest one, contest another — a split outcome is a real result.