Individual Versus Group Learning: Developmental and Social Differences in Two Selected Mouse Lines

Abstract

The intent of this study was to evaluate whether differences in brain excitability would influence learning. Two selectively bred lines of mice hypothesized to be different for this trait were employed, and a unique apparatus was used to evaluate learning in these animals when trained and retested in groups as well as individually. The results of Experiment 1 clearly demonstrate that short-sleep (SS) mice learn better than long-sleep (LS) mice and that adult animals learn better than young animals for both lines. Additionally, it was demonstrated that animals trained and tested in groups performed worse than individual animals. Experiment 2 was designed to ascertain whether the detrimental effect of grouping animals occurred on acquisition or retention. The results surprisingly show that the animals had to be grouped during both acquisition and retention for a deficit to appear. Experiment 3 analyzed how a “plant” animal affected the other animals in the group during retention. It was discovered that for LS mice the experience of the plant animal did not matter, but for SS mice only an animal naive to the shock experience could disrupt performance. These results are discussed in the context of social learning in animals.