Repeated Acquisition and Extinction of Barpressing in Rats and Guinea Pigs

Abstract

On each of 10 days rats and guinea pigs first barpressed for 15 reinforcements on a CRF schedule and then were immediately extinguished during an unsignalled 10-min. extinction session. Analysis of the number of bar-presses during each of 10 extinction sessions indicated a significant reduction for rats but not for guinea pigs because the level of barpressing remained consistently high immediately following reinforcement for the guinea pigs but declined progressively faster within successive extinction sessions for rats. Results support the idea that organisms with well developed sensory-motor capacities at birth are less able to inhibit previously rewarded responses than those with slower development.