Development of Passive Avoidance in Young Chicks: Dependence on Inhibition

Abstract

Chicks were tested at 16 hr., 2, 3, 4, 5, or 10 days posthatch for short-term response suppression to a novel auditory stimulus, indexed by drinking suppression (Exp. 2), for passive avoidance in a situation requiring extended response suppression, or for active-avoidance conditioning (Exp. 1). A different pattern of development was evident in active- and extended passive-avoidance tasks (Exp. 1). The former showed minimal improvement with age. Both short-term (Exp. 2) and extended passive avoidance improved significantly after Day 3, despite some short-term suppression at 16 hr. Although extended passive avoidance was no more difficult than active avoidance by Day 10, both trials to criterion and percentage success indicated its greater difficulty prior to Day 3. Implications for the involvement of general inhibitory control in the age-dependence of passive avoidance were discussed.