Shuttlebox performance in BALB/cByJ, C57BL/6ByJ, and CXB recombinant inbred mice: Environmental and genetic determinants and constraints

Male mice from nine strains (the CXB recombinant inbred set and their progenitors, BALB/cByJ and C57BL/6ByJ) were tested in a shuttlebox for two-way avoidance acquisition in an effort to resolve discrepancies between earlier studies. Mice were tested at one of three times of day (TOD) using one of three apparatus configurations. Analysis of variance revealed complex interactions between strain, apparatus configuration, and TOD. Subsequent analyses and tests of simple effects indicated very strong influences of apparatus configuration and/or TOD upon rate of acquisition in some strains, but not in others. C57BL/6 mice were relatively little affected by either variable; BALB/c mice were responsive to apparatus configuration but not to TOD. The recombinant inbred strains performed variously at levels that were either intermediate to, comparable with, or higher than those of the progenitors, depending upon the context of the testing situation. Genetic determination of behavior is, in part, a function of the particular context in which the behavior occurs. Both TOD and apparatus configuration are significant environmental factors.