Schedule-induced attack as a function of length of exposure to a fixed-time 90-sec schedule

Abstract

Twenty-four White King pigeons were exposed to a fixed-time (FT) 90-sec schedule of food presentation. For half of the subjects, a pictorial target was presented during the second session with the FT 90-sec schedule and throughout the remainder of the experiment. For the remaining subjects, the target was not made available until Session 26 with the FT 90-sec schedule. During early target availability, more subjects attacked in the late introduction condition. After extended exposure to the reinforcement schedule, however, similar numbers of subjects attacked in the two groups, eight in the early and nine in the late introduction group. The data suggest that when subjects are exposed only to a reinforcement schedule of moderate density, extended exposure with or without the target increases the probability that they will subquently attack the target.