An external phenomenon that has an influence on a system, by triggering or modifying an internal phenomenon; for example, a spur or incentive that drives a person to take action or change behaviour.

(linguistics) The idea that human language cannot be learned by young children with what information they are given, unless they already have an innate knowledge of language or universal grammar.

A signal (stimulus) that originates from outside an organism.

(behavioral psychology) A stimulus that does not reinforce an existing behavior in a subject and causes the subject to employ a new behavior.

(behavioral psychology) A stimulus, associated with reinforcement or punishment, that exerts control over a particular form of behavior; the subject discriminates between closely related stimuli and elicits a specific behavior more frequently or less frequently only in the presence of that stimulus.

plural of stimulus delta

plural of stimulus