Stimuli effects on optimal behavior in a sunk-cost situation with pigeons.

Abstract

The contribution of varying the response requirement frequency on the occurrence of escape-optimal and persistence-optimal behavior versus impulsive behavior was evaluated in food-deprived pigeons. According to an ABACA design, the subjects were exposed to the following arrangements of fixed ration (FR) response requirements and probabilities of presentation of each one: for the A conditions the arrangements were FR 10 p=0.50, FR 40 p=0.25, FR 80 p=0.125 or FR 160 p=0.125. For the B condition the arrangements were FR 10 p=0.125, FR 40 p=0.50, FR 80 p=0.25 or FR 160 p=0.125. For the C condition the set was FR 10 p=0.0625, FR 40 p=0.0625, FR 80 p=0.50 and FR 160 p=0.375. These FR response requirements with their respective probabilities were evaluated under two phases of the experiment, a signaled and an unsignaled one. Globally, it was found that the relative frequency of the FR response requirements controlled the occurrence of escape and persistence optimal behavior or impulsive behavior. These effects of the response frequency were modulated by the presence versus absence of a stimulus signaling the response requirement changes. These findings were interpreted as congruent with those previously reported in similar procedures.