Performance of pigeons in patterned sequences of rewarded and nonrewarded trials
Abstract
The performance of pigeons trained with patterned sequences of reward (R) and nonreward (N) for response to a given stimulus (S3) was studied in massed trials. 48 homing pigeons were used in 6 experiments. The patterns used were single alternation of R and N trials within each session; R trials in the 1st half of each session and N trials in the 2nd half; N trials in the 1st half of each session and R trials in the 2nd half; and successive acquisition and extinction with the R-to-N and N-to-R transitions occurring within sessions, between sessions, or both. Quasi-random partial reinforcement also was scheduled. The results point to patterning based on carryover (rapidly decaying sensory residuals or "short-term" memories of prior events) and on trial stimuli (stimuli correlated with number of trials or time elapsed since the start of a session), where carryover and trial stimuli are differentially reinforced. There was evidence as well of control by associatively reinstated representations or memories of recent N for response to S3 (N on earlier trials with S3 in the same session), although not of control by memory of more remote N (N on the final S3 trials of the preceding sessions) or by memory of R, recent or remote. (26 ref)