Define adjunctive behavior. What other term is used to refer to this class of behavior?
Correct Answer
Definition: Adjunctive behavior is an excessive and stereotyped pattern of behavior that emerges as a side effect of an intermittent schedule of reinforcement. This behavior is not required by the reinforcement contingency itself but appears reliably during the interval between the delivery of reinforcers.
The other term used for this class of behavior is schedule-induced behavior.
Adjunctive behavior, also known as schedule-induced behavior, refers to a peculiar and often excessive behavioral pattern that systematically develops when reinforcers are delivered on an intermittent schedule, particularly Fixed-Interval (FI) or Fixed-Time (FT) schedules. The behavior itself is not the target of reinforcement; instead, it emerges during the post-reinforcement period or the inter-reinforcement interval (IRI)—the time between one reinforcer and the next opportunity for reinforcement.
The most widely cited example is schedule-induced polydipsia, first demonstrated by J.L. Falk. In these experiments, rats deprived of food but not water were placed on an FI schedule where they received a food pellet every minute. During the one-minute intervals, the rats began to drink excessive amounts of water, sometimes consuming up to half their body weight in a single session, despite not being physiologically thirsty. This demonstrated that the drinking was not driven by a biological need but was an induced byproduct of the reinforcement schedule for a completely different activity.
Key characteristics of adjunctive behavior include its immediate onset following the consumption of the primary reinforcer and its tendency to increase in frequency as the time between reinforcers grows longer (up to a certain point). Other forms of this phenomenon include schedule-induced aggression, where an organism will attack another organism or an inanimate object during the IRI, and pica (the consumption of non-nutritive substances).
These behaviors are considered collateral or interim activities that fill the time while waiting for the next reinforcer. The principles may extend to human behavior, potentially explaining patterns like excessive doodling during a long lecture, nail-biting, or chain-smoking while waiting for an event. Ultimately, adjunctive behavior demonstrates that reinforcement schedules do not simply strengthen a target response but can also induce strong, stereotyped, and seemingly irrational collateral behaviors.thumb_upthumb_down
