Resistance to Extinction of a Lever Press in Spiny Mice (Acomys Cahirinus)

Abstract

The operant lever pressing of 12 adult male spiny mice ( Acomys cahirinus) was assessed during two phases of procedure: (1) CRF performance and subsequent extinction and (2) FR-10 performance and subsequent extinction. This highly precocial species showed a marked inability to inhibit previously reinforced responding during extinction following CRF performance. This result parallels extinction responding previously observed in guinea pigs, also an early developing species. Introduction of an FR-10 schedule resulted in a significant increase in lever pressing during performance sessions, establishing a contingency between responding and reinforcement that may not have existed during phase 1. However, complete extinction following FR-10 performance did not occur.