Effects of Changeover-Requirement Location on Between-Sequence Variation in Pigeons
Student: Hawken Hass
Major: Psychology
Mentors: Dr. Adam Doughty
Department: Psychology
Effects of Changeover-Requirement Location on Between-Sequence Variation in Pigeons
Isolating the variables responsible for the variation under a variability-reinforcement contingency is critical (e.g., a Lag schedule). One tactic has been to measure variation under a contingency requiring a changeover but not variability. Such studies have produced mixed results. The present experiment was conducted to clarify these mixed findings. Twelve experimentally naïve pigeons completed four-peck sequences under one of two contingencies. In one group, a four-peck sequence produced food only if it contained a changeover between the initial two pecks (e.g., RLLL). In a second group, a four-peck sequence produced food only if it contained a changeover between the final two pecks (e.g., RRRL). Between-sequence variation was considerably different between groups. U-value, number of different sequences, and number of dominant sequences all were higher for the pigeons exposed to the contingency that required a changeover at the end of the sequence. This increased variation occurred despite the absence of a variability contingency. However, the variation remained at a level lower than what is typically observed under a Lag schedule. The present research is consistent with the claim that a significant portion of the variation observed under a variability-reinforcement contingency is the result of reduced reinforcement-induced repetition.