Knowledge that Transforms

Because of its biological adaptive value, wariness of heights is widely believed to be innate or under maturational control. In this report, we present evidence contrary to this hypothesis, and show the importance of locomotor experience for emotional development. Four studies bearing on this conclusion have shown that (1) when age is held constant, locomotor experience accounts for wariness of heights; (2) “artificial” experience locomoting in a walker generates evidence of wariness of heights; (3) an orthopedically handicapped infant tested longitudinally did not show wariness of heights so long as he had no locomotor experience; and (4) regardless of the age when infants begin to crawl, it is the duration of locomotor experience and not age that predicts avoidance of heights. These findings suggest that when infants begin to crawl, experiences generated by locomotion make possible the development of wariness of heights.

One of the basic axioms of the rational theory of decision under uncertainty is Savage's (1954) sure-thing principle (STP) It states that if prospect x is preferred to y knowing that Event A occurred, and if x is preferred to y knowing that A did not occur, then x should be preferred to y even when it is not known whether A occurred We present examples in which the decision maker has good reasons for accepting x if A occurs, and different reasons for accepting x if A does not occur Not knowing whether or not A occurs, however, the decision maker may lack a clear reason for accepting x and may opt for another option We suggest that, in the presence of uncertainty, people are often reluctant to think through the implications of each outcome and, as a result, may violate STP This interpretation is supported by the observation that STP is satisfied when people are made aware of their preferences given each outcome

The cognitive “revolution” in psychology introduced a new concept of explanation and somewhat novel methods of gathering and interpreting evidence. These innovations assume that it is essential to explain complex phenomena at several levels, symbolic as well as physiological; complementary, not competitive. As with the other sciences, such complementarity makes possible a comprehensive and unified experimental psychology. Contemporary cognitive psychology also introduced complementarity of another kind, drawing upon, and drawing together, both the behaviorist and the Gestalt traditions.