Effects of genotype and postnatal experiences on activity, avoidance, shock threshold, and open-field behavior of rats.

Studied the effects of postnatal experience in 6 experiments on the activity, avoidance, shock threshold, and open-field behavior of 91 selectively-bred Ss from high-avoidance (RHA/Lu) strains and 93 from low-avoidance (RLA/Lu) strains. Significant differences were found between postnatal experiences in shuttle box activity, but strain differences were not significant. The high-avoidance Ss acquired avoidance learning significantly faster and had lower shock thresholds than the low-avoidance Ss. However, postnatal experience had significant effects on avoidance and shock threshold only in the high-avoidance Ss. No significant strain differences were found in open-field behavior, and the postnatal experience effects showed only higher order significant interactions. Results are discussed in the framework of quantitative genetics and a direct-action hypothesis of postnatal experience. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)