Concurrent second-order schedules: some effects of variations in response number and duration.
To examine the effects on concurrent performance of independent manipulations of response-unit duration and number, 6 hens were exposed to concurrent second-order schedules of reinforcement. Each first-order operant unit required completion of a fixed-ratio schedule within the time specified by a fixed-interval schedule, with one further response completing the fixed-interval schedule. The fixed-ratio and fixed-interval requirements comprising the first-order operant units were systematically and independently varied under three pairs of concurrent variable-interval schedules to produce differences in the first-order response and duration requirements (response and duration differentials). These manipulations produced consistent changes in response, time, and operant-unit biases. A 1:4 response differential biased the time and operant-unit measures towards the smaller fixed ratio, but to a degree less than the imposed response differential. The response-based biases favored the larger fixed ratio. Duration differentials of 4:1 and 8:1 biased the response and operant-unit measures towards the shorter fixed interval, again less than the imposed duration differential, but the time biases remained close to zero. Both sorts of differentials acted to bias operant-unit completions more systematically than the other measures, but undermatching to the differentials occurred. The undermatching appears to have arisen from a pattern of fix and sample (in which visits to the less preferred alternative involved only a single completed operant unit) under combinations of unequal operant-unit requirements and reinforcer rates. The response and time bias measures appeared to arise as by-products of the changes in operant-unit completions.
Sealey
Diane M
DM
University Of Waikato, Hamilton, New Zealand.
Sumpter
Catherine E
CE
Temple
W
W
Foster
T Mary
TM
D000818:Animals; D001070:Appetitive Behavior; D001245:Association Learning; D001288:Attention; D015982:Bias; D002645:Chickens; D002755:Choice Behavior; D003216:Conditioning, Operant; D004193:Discrimination Learning; D005260:Female; D011340:Problem Solving; D012055:Reinforcement Schedule