Conditioned suppression in goldfish as a function of shock-reinforcement schedule

The conditioned suppression technique (Estes and Skinner, 1941) was employed to study the effects of partial-shock reinforcement in the goldfish. Lever-pressing behavior of hungry goldfish was suppressed in the presence of a flashing light that had been previously paired with electric shocks. Fish that acquired the suppression under 50% and 100% shock-reinforcement, respectively, were subjected to repeated presentations of the flashing light alone. This procedure revealed a more rapid extinction of the suppressed behavior in the 50% than in the 100% shocked group. The finding was compared with those from other experiments and possible reasons for the differences were examined.