Evidence for general cognitive ability (g) in heterogeneous stock mice and an analysis of potential confounds

The heterogeneous stock (HS) is a genetically outbred line of mice established more than 30 years ago from an 8-way cross of C57BL/6, BALB/c, RIII, AKR, DBA/2, I, A/J and C3H inbred mouse strains. The present study compared the performance of 40 HS mice across a battery of diverse cognitive tasks under a variety of motivations. Indices of emotionality were also included in order to assess their influence on performance. All measures of ability loaded positively on an unrotated first principal component that accounted for 31% of the variance, suggesting the presence of a common factor of general cognitive ability (g) underlying all tasks. A first factor derived from anxiety indices correlated nonsignificantly with all cognitive tasks and nonsignificantly with this g factor, supporting the hypothesis that the factor is cognitive rather than temperamental in nature. The factor was also robust in relation to outliers and sex differences, accounting for 28% of the variance after removal of outlier individuals and also after correcting for variance owing to sex differences. A general cognitive ability (g) appears to underlie the performance of HS mice on a battery tapping diverse cognitive demands.