What is a reaction-time distribution?

A span task presents items (digits, letters, locations) and asks you to repeat them in order, or sometimes in reverse. Forward span is closer to simple storage; backward and complex spans add extra work. Licensed batteries sometimes include a digit-span subtest as one slice of a much larger, normed composite. The original sequences on this site are classroom toys. They do not estimate working-memory capacity as a scientific k, do not replace a Wechsler span, and do not print an IQ. Device lag, chunking and a tiny run would wreck any serious estimate. Pratique — pas un QI clinique.

Set shifting (a cousin of cognitive flexibility) is the ability to drop one mapping and use another: colour instead of shape, number instead of letter. Laboratories study it with card sorts, trail making B, and switch-cost designs. Wisconsin-card-sort lite hides a rule and changes it; trail-making-b lite alternates 1-A-2-B. Those pages are original toys. They do not diagnose frontal injury, do not replace the WCST, and do not print a flexibility IQ. Pratique — pas un QI clinique.

In the multicomponent working-memory sketch associated with Baddeley, the “central executive” is a label for attention control: what to hold, what to drop, how to coordinate a second task. It is not a little person in the head and not an IQ index. Phonological loop and visuospatial sketchpad pages on this site cover the storage sides. Operation-span lite, keep-track lite and counting-span lite add extra work on purpose. Those originals are not a CE battery and not a clinical IQ. Pratique — pas un QI clinique.

In switching experiments you repeat a rule or you change it. The difference in speed or errors is a switching cost (sometimes separated from mixing costs when blocks include both trial types). Task-switch lite and odd-even switch lite illustrate the idea with original mappings. Trail-making B lite is a spatial cousin: number then letter. None of these estimates a millisecond IQ. Device lag on the web is often larger than the effect you came to measure. Pratique — pas un QI clinique.

A go stimulus maps to a response. On some trials a stop signal appears and you should withhold. Researchers often vary the delay (SSD) to estimate stop-signal reaction time (SSRT). That estimate needs many trials and a model. Stop-signal lite on this site uses a simple stop cue. It does not track SSD, does not report SSRT, and is not an inhibition IQ. Go/no-go and anti-saccade lite are related family members with different mappings. Pratique — pas un QI clinique.