Examining the Effect of Changeover Delays on Response Patterning in Pigeons
Kentaro Kaneki ’17 and J. Mark Cleaveland (Psychology)
Habit formation develops when an animal repeatedly performs a sequence of behaviors that produce a favorable outcome. During the development of such habits, individual behavioral elements of the overall pattern become increasingly unresponsive to local outcomes. This psychological process is sometimes referred to as stimulus-response, or S-R learning. S-R learning has been localized to brain structures (i.e., the lateral dorsal striatum) and has been studied across many experimental procedures. Surprisingly, one element of habit formation that has not been well-studied involves the role of behavioral timing in the execution of habits. Behavioral timing would be defined as the transition between behavioral elements as a function of their interresponse time (IRT). A musician, for example, when learning a piece of music learns not only note sequences but also timing between these notes. Our URSI project was designed to investigate the role of response timing and habit formation via both a quantitative model and a choice experiment utilizing pigeons. The model proposes a response clock whose intervals are weighted by reinforcement delivery according to a “leaky integrator.” The weighted timing function is then used to generate a response element. To test this model, we conducted a choice experiment with pigeons. In the experiment birds had two pairs of two reinforcement schedules, with only one pair presented at a time. Each schedule pair consisted of a variable-interval (VI) 30 VI 60. However, the pairs differed as to whether switches from one schedule to another immediately produced reinforcement or not. This procedure is known as a changeover delay (COD) which serves to punish the act of switching. By combining the results of this experiment we hope to improve / test the validity of our quantitative model – a model that generates behavioral habits as a function of IRTs.