Behavior analysis is an approach to psychology that concerns itself primarily with observing, analysing and attempting to understand and predict the way humans behave and interact.
Low-rate operant behavior that occurs as a function of an S^. For example, the probability of putting coins in a vending machine with an "out of order" sign on it is very low.
Any event in the presence of which a target behavior is likely to have consequences that affect its frequency. Discriminate stimuli include SDs ("ess-dees") and S(s ("ess-deltas").