Effect of reward probability on spatial and temporal variation.
Gharib, Derby, and Roberts (2001) proposed that reducing reward expectation increases variation of response form. We tested this rule in a new situation and asked if it also applied to variation of response location and timing. In 2 discrete-trial experiments, pigeons pecked colored circles for food. The circles were of 6 possible colors, each associated with a different probability of reward. Reducing reward expectation did not affect peck duration (a measure of form) but did increase horizontal variation of peck location and interpeck-interval variation. The effect of reward probability on the standard deviation of interpeck intervals was clearer (larger t value) than its effect on mean interpeck interval. Two datasets from rats had similar interresponse-interval effects.
Department of Psychology, University of California Los Angeles, Los Angeles, CA 90095-1563, USA.
W David
WD
Stahlman
Seth
S
Roberts
Aaron P
AP
Blaisdell
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D010856:Columbidae / Q000502:physiology; D003216:Conditioning, Operant / Q000502:physiology*; D008297:Male; D011336:Probability; D012055:Reinforcement Schedule; D012201:Reward; D013028:Space Perception / Q000502:physiology*; D013998:Time Perception / Q000502:physiology*