Abstract
Each of 3 experiments demonstrated that female Sprague-Dawley albino juvenile rats (n = 24) become increasingly active during 10 consecutive trials in the open field; adults (n = 24) did not show this day-to-day change. Age-related activity change was unaffected by food deprivation and is interpreted to be a consequence of the greater curiosity and ease in familiarization with a novel environment among juveniles. The greater intensity of ambulation among immature Ss may provide an explanation for age-related differences in appetitive learning. (24 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)