Irreversibility of imprinting after active versus passive exposure to the object.

64 isolated Peking ducklings were reared for 4 days with a hanging colored object (passive training). Half of the Ss also received 3 1-hr following sessions with the object (active training). Findings indicate that both groups chose the imprinting object in a simultaneous choice test administered on Day 5, but the preference of active-trained Ss was more robust than of passive-trained Ss. Each S was then reared with an object of a different color and shape. The preference for the 1st object was maintained in active-trained Ss, but not in passive-trained Ss. These results were also found when the objects were removed from the cages for 4 days. Findings suggest that preferences established during the sensitive period for imprinting can be eliminated (but not necessarily reversed) in Ss that are prevented from following the original object, but they are resistant to change in Ss given the following experience. A hypothesis is presented that emphasizes the importance of reafference and activation of brain stem pathways involved in following the formation of specific affiliative bonds. (44 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)