With these limitations in mind, locomotion and the measures most closely associated with it, rearing and head dipping, are the most heritable and interrelated measures in the current experiments. Selective breeding of HEB and LEB mice resulted in populations of mice that displayed correlated differences in locomotion during the selection test. Object and novel environment preference, which demonstrated much smaller between-strain differences, tended to resemble each other phenotypically more than they did any other measure. Spontaneous alternation likewise tended to be unrelated to the other measures. Similar to the results obtained with the inbred strains, HEB and LEB mice did not show consistent differences in any of these measures, including the phenotypically similar object preference task, further indicating that these measures are largely dissimilar.
