The Timing of Bar-Pressing Behaviour

Abstract

The time spent by a rat in a bar-pressing situation is made up of active time spent n pressing, eating time, and extra time spent in other activities. With a well trained rat, active time and extra time are small, and eating time mainly determines the rate of reward delivery. Active time is affected by a change of weight on the bar, the time between reward deliveries is affected by the amount of reward, and the extra time is affected by extinction conditions. There is not a one-to-one correspondence between periods of activity at the knob and rewards. The term “response” and some variables based on it are given empirical referents, which show that much research and theorizing on bar-pressing behaviour has been concerned with only a small selection of the rat's bar-pressing activities. Some reasons for this restriction are the use of the simple weighted bar, the lack of a rationale for bar-pressing research, and the practice of not watching the rat during an experiment.