Abstract
The nonassociative model of fear development has been used to explain the absence of conditioning, events and failure to see latent inhibition effects in many 'evolutionary relevant' fears. The current nonassociative model has relied, however, on relatively contentious distinctions between what constitutes an 'evolutionary relevant' fear stimulus versus an 'evolutionary neutral' fear stimulus. It was proposed instead that a model based on the context stability of the fear stimuli-may provide a more parsimonious and effective framework for the nonassociative account, with changes of context attenuating latent inhibition towards a stimulus' basic fear properties rather than the stimulus itself. The aim of the present study was to compare an evolutionary-relevance framework for the nonassociative pathway of fear against a context-stability framework by examining the development of latent inhibition in Dental Fear (context-stable/evolutionary-neutral), Height Fear (context-unstable/evolutionary-relevant), and Driving-Related Fear (context unstable/evolutionary neutral) using prospective longitudinal data from the Dunedin Multidisciplinary Health and Development Study. Both the evolutionary-relevance and context-stability frameworks of the nonassociative model predicted that latent inhibition would occur with fears that were 'context-stable' and 'evolutionary-neutral' but would not occur for fears that were 'context-unstable' and 'evolutionary-relevant'. Fears that were 'context-unstable' but 'evolutionary-neutral', however, would be expected to show latent inhibition only under an evolutionary-relevance framework and were not expected if context-stability provided a more effective' framework. The results provided support for the 'context-stability' framework over an 'evolution-relevance' based framework for the nonassociative model, with significant latent inhibition seen in Dental Fear but not in either Height or Driving-Related Fear. Results were discussed in regard to the phylogenetic history of basic fear stimuli properties, with innate fear proposed to occur to the specific life-threatening properties of the stimuli rather than to the stimuli themselves. The possibility of an innate latent inhibition propensity in all individuals and the implications for fear development were discussed, and possible future research and clinical fear treatments stemming from the present findings addressed.