The present studies were conducted to determine (a) the form of the retention curve for an incompletely learned appetitive task, and (b) the effect of adrenalin and sodium amobarbital on the "Kamin effect". In Expt. 1, rats were tested for retention of an appetitively motivated approach response, and Expt. 2 investigated the retention of an approach-avoidance spatial conflict. No "Kamin effect" was observed in Expt. 1. The saline controls of Expt. 2 demonstrated a reliable "Kamin effect", and adrenalin and sodium amobarbital, administered prior to retention testing, reliably increased and decreased, respectively, the behavorial indices of fear, and abolished the "Kamin effect". The results were interpreted as demonstrating that fear initially decreases over time. Some suggestions as to the mechanism of this effect were offered. © 1972.