Extinction can be enhanced by a concurrent excitor

J Exp Psychol Anim Behav Process. 2000 Jul;26(3):251-60. doi: 10.1037//0097-7403.26.3.251.


Five experiments used rat subjects to investigate the impact on extinction of the presence of other conditioned stimuli. In Experiments 1 (Pavlovian magazine approach) and 2 (instrumental discriminative training), an excitatory stimulus (X) was extinguished alone, in conjunction with a previously reinforced other stimulus (A), in conjunction with previously nonreinforced other stimulus (B), or it was spared extinction. Responding during extinction was greatest to AX, and subsequent testing of X alone showed AX extinction to have produced the most decrement to X. Experiment 3 found similar results using a within-subject design. Experiment 5 continued separate reinforced presentations of A during extinction. This procedure not only promoted extinction of X but also converted it into a conditioned inhibitor. These experiments bear on the mechanisms of overshadowing and stimulus processing, as well as provide information on the determinants of extinction.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Analysis of Variance
  • Animals
  • Conditioning, Classical*
  • Conditioning, Operant*
  • Extinction, Psychological*
  • Male
  • Rats
  • Rats, Sprague-Dawley
  • Reinforcement, Psychology*