Effect of effort on resistance to extinction of the bar-pressing response

This study was designed to obtain more information on the relation between effort and resistance to extinction when all subjects receive equal acquisition experience on each effort level at which the response is subsequently to be extinguished. Twenty-four subjects were given 120 reinforcements on each of three weighted bars of 5, 40 and 70 gm. They were then ordered into three groups, each extinguished on one effort level. Analysis of the number of responses emitted in six daily 20-min. extinction sessions showed that resistance to extinction was not related to the amount of effort expended in extinction.