Intracranial stimulation and natural reward: Differential effects of trial spacing

Abstract

Rats rewarded with intracranial stimulation (ICS) in a runway ran faster after a decrease in intertrial interval and slower after an increase. The effect was not found in rats rewarded with water under highly similar conditions. The effect appears on the first trial. Therefore, it must be attributed to the decay of a drive-like process, and not to a change in the incentive value of ICS. © 1967, Psychonomic Press. All rights reserved.