Effects of conditioned aversive stimuli presented during tonic immobility in guinea pigs.

Abstract

The duration of and susceptibility to tonic immobility were measured in 3 groups of albino and pigmented guinea pigs (N = 27) while a train of intense tone bursts was presented. In 1 group, the tone bursts had been previously associated with painful shock stimuli. The 2nd group had previously experienced the tone bursts alone, and the 3rd group had previously received shocks without the train of tone bursts. Results indicate that both groups which had previously received shock exhibited increased susceptibility to immobilization, and the no-shock group showed a decline in duration when tone bursts were presented. Results could not be easily interpreted to support the fear hypothesis. Explanations involving "sensitization" and "learned helplessness" are proposed. (PsycINFO Database Record (c) 2006 APA, all rights reserved)