Effects of two procedures for varying information transmission on observing responses.

Two experiments were conducted with pigeons to examine the effects of procedures that varied information transmission on observing responses. The basic procedure for Experiment I was one in which a trial terminated in either non-contingent reinforcement or timeout. Pecking during a trial produced either green (positive) or red (negative) keylights. If no pecking occurred no differential stimuli appeared. The probability of positive trials was either 0.25, 0.50, or 0.75. Observing response rates and relative frequencies of occurrence were highest when the probability of positive trials was 0.25 and lowest at 0.75. In Experiment II, a modified chain procedure was used in which responding produced either red or green lights. Reinforcement or timeout followed light onset by 15 sec. The correlation between the stimuli and the event at the end of the trial (reinforcement or timeout) was varied. Reinforcement followed green 100%, 90%, 70%, or 50% of the time that green occurred. Since the overall probability of reinforcement remained at 0.50, reinforcement followed red in either 0%, 10%, 30%, or 50% of the time that it occurred. The rate of responses that produced these stimuli varied as a function of the correlation. The greater the probability of reinforcement after green, the higher the response rate.