| Abstract: | Investigated in 2 experiments, ontogeny and interdependence of genetically selected avoidance and open-field behaviors in 6 genetic lines (e.g., MNR/Har/Lu, RCA/Lu), involving 1,018 rats, and 3 developmental models (longitudinal, cross-sectional, and generational). In selected lines, behaviors varied with age (either 21-, 35-, 70-, or 100 days of age), depending upon the genetic selection; in the control (random bred) line, no such effects were found. Between the lines selected for high (RHA) and low (RLA) rates of 2-way active avoidance, ontogenetic differences in the selected behavior emerged as Ss grew older, whereas between the lines selected for high (MR) and low (MNR) frequency of open-field defecation, the differences in the selected behavior were present at all stages of development. In Ss' unconditioned escape response to footshock, the differences were present at all stages. The relationship between avoidance response and open-field defecation (emotional reactivity) was not linear but suggestive of a curvilinear inverted-–U function. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
