Feist−Feist: Theories of
Personality, Seventh
EditionV. Learning Theories 15. Skinner: Behavioral
Analysis(^462) © The McGraw−Hill
Companies, 2009
a low response number, and then increase to a higher rate of response. A pigeon re-
warded every third response on the average can build to a VR 6 schedule, then VR
10, and so on; but the mean number of responses must be increased gradually to pre-
vent extinction.After a high mean is reached, say, VR 500, responses become ex-
tremely resistant to extinction. (More on rate of extinction in the next section.)
For humans, playing slot machines is an example of a variable-ratio schedule.
The machine is set to pay off at a certain rate, but the ratio must be flexible, that is,
variable, to prevent players from predicting payoffs.
Fixed-Interval With the fixed-interval schedule,the organism is reinforced for
the first response following a designated period of time. For example, FI 5 indicates
that the organism is rewarded for its first response after every 5-minute interval. Em-
ployees working for salary or wages approximate a fixed-interval schedule. They are
paid every week, every 2 weeks, or every month; but this pay schedule is not strictly
a fixed-interval schedule. Although pigeons typically show a spurt in work toward
the end of the time period, most human workers distribute their efforts fairly evenly
rather than loafing most of the time and then showing an end-of-the-period spurt.
This situation is due in part to such factors as watchful supervisors, threats of dis-
missal, promises of promotion, or self-generated reinforcers.
Variable-Interval A variable-interval scheduleis one in which the organism is re-
inforced after the lapse of random or varied periods of time. For example, VI 5
means that the organism is reinforced following random-length intervals that aver-
age 5 minutes. Such schedules result in more responses per interval than do fixed-
interval schedules. For humans, reinforcement results more often from one’s effort
rather than the passage of time. For this reason, ratio schedules are more common
than interval schedules, and the variable-interval schedule is probably the least com-
mon of all.
456 Part V Learning Theories
Because slot machines pay off on a variable-ratio schedule, some people become compulsive gamblers.