“…Thompson and Spencer (1966) state that one of the nine parametric characteristics of habituation is that "habituation of response to a given stimulus exhibits stimulus gen-eralization to other stimuli." A large number of previous studies have shown that following habituation to one stimulus an intermodal or intramodal change in stimulus characteristics leads to increased responsiveness in adult humans (Allen, Hill, & Wickens, 1963;Badia & Defran, 1970;Coombs, 1938;Hare, 1968;Houck & Mefferd, 1969;Korn & Moyer, 1968;Weisbard & Graham, 1971;Zimmy, Pawlick, & Sour, 1969), human infants (Bernstein, Kessen, & Weiskopf, in press;Bridger, 1961), and other organisms (Bagshaw & Benzies, 1968;Bagshaw, Kimble, & Pribram, 1965;Peeke & Peeke, 1973). Although there is less abundant evidence that the amount of response increment is a function of the amount of difference between training and test stimuli, this relationship has now been demonstrated in several different organisms by using a variety of response measures (Apelbaum, Silva, Frick, & Segundo, 1960;Gorman, 1967;Engen & Lipsitt, 1965;Greer, 1969;Sokolov, 1963;Williams, 1963).…”