Schedules of Reinforcement


Schedules of reinforcement are the precise rules that are used to present (or to remove) reinforcers (or punishers) following a specified operant behavior. These rules are defined in terms of the time and/or the number of responses required in order to present (or to remove) a reinforcer (or a punisher). Different schedules schedules of reinforcement produce distinctive effects on operant behavior.



Interval Schedule

Interval schedules require a minimum amount of time that must pass between successive reinforced responses (e.g. 5 minutes). Responses which are made before this time has elapsed are not reinforced. Interval schedules may specify a fixed time period between reinforcers (Fixed Interval schedule) or a variable time period between reinforcers (Variable Interval schedule).

Fixed Interval schedules produce an accelerated rate of response as the time of reinforcement approaches. Students' visits to the university library show a decided increase in rate as the time of final examinations approaches.

Variable Interval schedules produce a steady rate of response. Presses of the "redial" button on the telephone are sustained at a steady rate when you are trying to reach your parents and get a "busy" signal on the other end of the line.


Ratio Schedule

Ratio schedule require a certain number of operant responses (e.g., 10 responses) to produce the next reinforcer. The required number of responses may be fixed from one reinforcer to the next (Fixed Ratio schedule) or it may vary from one reinforcer to the next (Variable Ratio schedule).

Fixed Ratio schedules support a high rate of response until a reinforcer is received, after which a discernible pause in responding may be seen, especially with large ratios. Sales people who are paid on a "commission" basis may work feverously to reach their sales quota, after which they take a break from sales for a few days.

Variable Ratio schedules support a high and steady rate of response. The power of this schedule of reinforcement is illustrated by the gambler who persistently inserts coins and pulls the handle of a "one-armed bandit."


Extinction

A special and important schedule of reinforcement is extinction, in which the reinforcement of a response is discontinued. Discontinuation of reinforcement leads to the progressive decline in the occurrence of a previously reinforced response.

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