The structure of individual differences in heterogeneous stock mice across problem types and motivational systems.

Sixty Heterogeneous Stock (HS) mice received a battery of six problem-solving tasks and three control procedures. The problem-solving tasks included Hebb-Williams, a place learning task conducted in a plus maze, radial maze, a working memory test following the radial maze, a set of detour problems and a visual non-matching to sample task. The control procedures consisted of land and water activity measures and a light-dark test. The correlation matrix derived from these tasks did not exhibit positive manifold, that is, positive correlations across all problem-solving tasks. Principal components analysis reduced the correlation matrix to four components with eigenvalues exceeding 1.0. Instead of the general factor solution common in the study of human problem-solving, this component structure appeared more congenial to a modular interpretation, with the four components each explaining approximately the same magnitude of matrix variance.