“…Zajonc familiar stimulus, reduces distress calling (Zajonc,Markus,& Wilson 2) even when the prior exposure to the stimulus occurred prenatally (Rajecki, 1972). In a series of studies, Hoffman (Hoffman, Barrett, Ratner,& Singer, 1972;Hoffman, Eiserer, & Singer, 1972;Hoffman, Ratner,& Eiserer, 1972) employed the distress calling of ducklings to investigate, among other things, the changes in behavioral control exerted by different stimuli and differing amounts of experience with those stimuli. In all these studies, vocalization behaviors are taken as an index of attachment to the familiar.…”