The social release paradigm: investigations of restrainer aversion

Abstract

In the social release paradigm, one rat is restrained in a plastic tube and a cagemate can open the restrainer door to release the rat from outside. Researchers have debated whether release is empathetically motivated or better understood as operant behavior reinforced by social contact. One fundamental assumption underlying interpretations of door opening in terms of helping or empathy is that being restrained in the tube is aversive to the trapped rat. The current study aimed to shed light on this controversy by investigating restrainer entries and re-entries by the free and formerly restrained rats after release, respectively. We hypothesized that if being restrained is aversive, the formerly restrained rat would make fewer restrainer re-entries following release than the free rat due to its aversive learning history with the restrainer. The results show that the free and formerly restrained rats explored the restrainer equally often following release, thus supporting prior research suggesting that being trapped in the restrainer is not aversive. The observation that the two rats made more positive 50kHz vocalizations before than after release also lend some support to this suggestion.