To assess potential differences across passes, the responses of C57BL/6J and DBA/2J mice were compared on each dependent measure by two-way ANOVA (genotype X pass). Within these two strains, some relatively small main effects of pass were observed for some variables, but, with the exception of head dipping on a hole-board, no significant genotype X pass interactions were observed. Although the difference in head dipping was clearly unexpected, it is likely that this interaction is stochastic in origin considering the large number of dependent variables assessed. Thus, to simplify the analysis and presentation of the data, all correlations presented ignore any effects of pass. However, inbred strain-effect sizes are shown separately for each pass in Table 2 as well as collapsed across pass in Table 1.
