Reversibility of imprinting.

Abstract

Isolated chicks, reared for 3 days with a hanging colored object, chose this object in a simultaneous choice test. Each S was then reared with an object of different color or shape and this became the preferred object after 3 or 6 days. The preference for the 2nd object was maintained when objects were absent for 3 days. Yellow and rectangular objects were less preferred than were blue, green, and ball-shaped objects. Newly-hatched chicks chose a ball in preference to a rectangular object. Color or shape preferences established during the critical period for imprinting can be reversed, although some stimuli may be intrinsically preferred.

SCHEDULES OF ELECTRIC SHOCK PRESENTATION IN THE BEHAVIORAL CONTROL OF IMPRINTED DUCKLINGS1

“…Instead, the results support a more conventional learning interpretation, which suggests that pairing a stimulus with shock during and after imprinting reduces choice of that stimulus. The duckling's choice of a given stimulus is neither irreversible nor rigidly stable, a finding confirming that of other individuals (Hinde, 1962;Salzen and Meyer, 1968). It also appears that imprinting, as measured by a choice test, is not enhanced by aversive stimulation.…”

“…Whether response-independent shock could modify clear-cut choice behavior remains to be investigated. However, on the basis of research indicating that changes in preference can be accomplished by mere exposure to a second stimulus (Stratton, 1971;Salzen and Meyer, 1968), it seems likely that choice of a strongly preferred stimulus would also be suppressed by shock delivered in its presence or dependent on the choice of that stimulus.…”

Visually imprinted maternal preference in ducklings is redirected by social interaction with siblings

“…The finding that the visually imprinted maternal preference is so readily redirected by social rearing is in contrast with conventional interpretations of maternal imprinting, which hold that imprinted preferences are very strong and resistant to change, even if not totally irreversible (Lorenz, 1937;Hess, 1959;Schein, 1963). While the present results are certainly not the first to demonstration the redirection of object attachment or preference (see Salzen & Meyer, 1968;Zajonc, Reimer & Hausser, 1973;Einsiedel, 1975 for examples of reversibility for nonnatural objects in domestic chicks), the redirection of visual preferences for natural models by young ducklings shown here strongly suggests that the strength or permanence of maternal attachments reported in the vast imprinting literature is, at least in part, an artifact produced by the isolation rearing conditions typically employed in studies of imprinting. Under the nonisolated social rearing circumstances which occur in nature, active maternal involvement would appear to be important not only to the establishment but also to the maintenance of the social attraction to the mother shown by young ducklings.…”

Reconsideration on primacy effect of imprinting in ducklings

“…This has also been called the primacy effect (Hess, 1973). However, Salzen and Meyer (1968) reported that an imprinted preference should he capable of being reversed if the imprinted bird is confined with a new stimulus in the absence of the original object. Many other studies, using artificial imprinting objects such as colored balls, have reported reversal in preference (Cherfas & Scott, 1981;Einsiedel, 1975;Zajonc, Reimer, & Hausser, 1973).…”