Effects of number of CS-US pairings on the strength of conditioned frustration in rats

Abstract

Following 45 placements to a wet-mash reward, groups of rats received 0, 10, 20, or 40 frustration-conditioning trials during which primary frustration was paired with the apparatus cues plus a distinctive CS. Other groups received 0, 10, or 20 pairings of primary frustration and apparatus cues alone. In the CS condition, learning of a hurdle-jumping response which terminated the CS was nonmonotonically related to the number of frustration-conditioning trials on the first of 2 test days. Performance increased with the number of conditioning trials up to 20, then decreased following 40 such trials. Among groups which did not receive the CS during conditioning or testing, only subjects in the zero-pairing condition showed evidence of learning. The results were interpreted as supporting the conclusion that conditioned frustration had acquired aversive motivational properties since its effectiveness was found to vary systematically with the number of conditioning trials. It was further concluded that the superiority of hurdle-jumping performance by CS groups relative to NCS groups was the result of both a higher level of frustrative motivation and greater frustration reduction following the response for the former groups.