Conditioned drinking as avoidance learning

Conducted 4 experiments with a total of 104 male Sprague-Dawley albino rats. Blocking the robust conditioned drinking response following conditioning eliminated the isotonic procaine conditioned response (CR) but not the hypertonic procaine CR. Ss allowed to drink in the box during conditioning formed a larger CR than Ss merely injected with hypertonic or isotonic procaine who were prevented from drinking in the box: response blocking during extinction eliminated the latter CR. The CR to hypertonic procaine could also be eliminated if no experience of drinking water in the box occurred either during baseline or during conditioning. Blocking the drinking response, like blocking shock avoidance, markedly reduced its high resistance to extinction. Results suggest that rats overdrink to avoid anticipated illness, and fail to extinguish partially because they are never exposed to the fact that no illness will occur even if no drinking occurs. (PsycINFO Database Record (c) 2006 APA, all rights reserved).