Do rats show a Mozart effect?

The “Mozart effect” is an increase in spatial reasoning scores after listening to a Mozart piano sonata. Both the production and interpretation of the effect are controversial. Many studies have failed to replicate the original effect. Other studies have explained a Mozart effect as being caused by changes in arousal or differences in preferences of the listener. F. H. Rauscher, K. D. Robinson, and J. J. Jens (1998) reported that rats learned to complete a T-maze more quickly if they had been exposed in utero and reared hearing a Mozart piano sonata. They concluded that the result indicated a direct effect of the music on brain development and contradicted competing accounts of arousal or preference. This article is an analysis of the experiment by Rauscher et al. The in utero exposure would have been ineffective because rats are born deaf. A comparison of human and rat audiograms, in the context of the frequencies produced by a piano, suggests that adult rats are deaf to most notes in the sonata. The successful performance of the Mozart group may be explained by the incomplete use of random assignment of subjects to groups and by experimenter effects in the construction of groups. The results of Rauscher et al. (1998) do not provide strong support for the existence of the Mozart effect.