Choosing to Vary and Repeat

Abstract

Can animals choose to vary their behaviors or to repeat them, depending on the rewards they earn for behaving variably versus repetitively? To answer this question, pigeons were rewarded for four-response sequences made to left (L) and right (R) disks. A “varied” sequence differed from each of the previous three sequences, and a “repeated” sequence was the same as some one of the previous three. For example, if a pigeon had generated sequences LLLL. LLLR, and LLRR in that order, then an RRRR sequence in the next trial was defined as a variation, whereas LLLL was a repetition. Two experiments showed that frequencies of varied and repeated sequences depended on the frequencies with which they were reinforced, with a “matching” relationship accounting for the results. It was concluded that pigeons' choices to vary or repeat parallel their choices between simpler response alternatives, a result consistent with the hypothesis that behavioral variability is influenced by its consequences. This finding may help to explain the “voluntary” or “free” nature of operant behavior.