Traditionally, CR magnitude in classical conditioning was thought to be dependent only upon properties of the CS and UCS. This study investigated the cognitive factor of S’s expectancy of shock and his anxiety on GSR amplitude. Each S received 20 conditioning trials on a 50% random reinforcement schedule and had to state his expectation of shock before each trial. There was a significant correlation between verbalized expectancy and CR amplitude. High anxious Ss extinguished more slowly than low anxious Ss and had greater mean shock expectancies during acquisition.