The Preference-For-Signaled-Shock Phenomenon: Signal Salience in Symmetrical-Choice Procedures

The preference-for-signaled-shock (PSS) phenomenon is theoretically important, but the relevant data base, even when limited to symmetrical-choice procedures is not unequivocal. The two experiments using rats as subjects reported here were designed to determine whether increasing the salience of the contrast between signaled and unsignaled states would increase both the strength of preference as well as the specifiability of the controlling parameters. Experimenent 1 showed a reliable, rapidly emerging, and strong (over 95%) PSS effect, but some complicated interactions between the signaling and other factors suggested that this method of manipulating salience brought its own problems of interpretation. The results of Experiment 2 also yielded a reliable, rapidly emerging and strong (over 95%) PSS phenomenon which, however, was unaffected by the color vs. stripe width (salience) manipulation.