The present results indicate that there are genetic influences in each of the tests considered, and, in the case of preference for objects, this influence is relatively small. The pattern of genetic correlations from the inbred strain experiments suggests that, whereas most of the behaviors putatively indexing aspects of novelty seeking correlated relatively highly with locomotion, the novelty-related behaviors are at best modestly genetically correlated with each other. This pattern was also seen in the selectively bred HEB and LEB lines, which showed large, correlated differences in locomotor activity in all apparatus but did not consistently differ in performance in other tasks that putatively measured aspects of novelty seeking other than head dipping. Given the very different modalities of responses recorded in each task (locomotion, time spent in an area, choice behavior, etc.), this finding of few correlations may not be unexpected. However, it implies that the trait being measured by the various tasks either is not isomorphic across the behavioral assays or is phenotypically complex, and each task is sensitive to certain different underlying aspects of the putative trait.
