Evidence for a non-associative model of the acquisition of a fear of heights.

Theories that fear results from previous traumatic experience (i.e. conditioning theories) have enjoyed widespread support for over half a century. Recent research, however, has cast doubt on the validity of these models in some specific phobias. Two studies on the etiology of height phobia have obtained findings consistent with a non-associative, evolutionary explanation of fear acquisition (Menzies and Clarke, 1993a, Behaviour Research and Therapy, 31, 355-365; Menzies and Clarke, 1995a, Behaviour Research and Therapy, 33, 795-805). Unfortunately, the retrospective nature of these studies limits the conclusions that can be drawn from these data. Like all retrospective research, these studies depend on adult subjects imperfect ability to recall conditioning events that may have occurred many years earlier. The present investigation overcomes these methodological shortcomings by examining the relationship between putative conditioning events before the age of 9 yr and the presence of height fear at ages 11 and 18 yr in a large birth cohort studied longitudinally. To our knowledge this is the first study that has prospectively examined the relationship between relevant traumatic events early in life and the onset of height fear in late adolescence. No positive relationship was found between a history of falls resulting in injury (i.e. fracture, dislocation, intracranial injury or laceration) before the age of 9 and fear of heights at age 11 or 18. Interestingly, falls resulting in injury between the ages of 5 and 9 occurred more frequently in those without a fear of heights at 18 (P < 0.01)--a finding in the opposite direction to that predicted by conditioning theory but consistent with non-associative theories of fear acquisition. In general, the results provide strong support for non-associative models of fear and are difficult to reconcile with conditioning theories.