Natural selection and fear regulation mechanisms

Non-associative fear acquisition: a review of the evidence from retrospective and longitudinal research

It is axiomatic that the capacity to experience fear is adaptive, enabling rapid and energetic response to imminent threat or danger. Despite the generally accepted utility of functional fear, the nature of maladaptive fear remains controversial. There is still no consensus about how specific fears and phobias are acquired and modulated. Two major schools of thought are apparent: those suggesting dysfunctional fear arises largely as the result of associative-conditioning processes versus those who favour more biologically based etiological explanations. In this regard, the non-associative model of fear acquisition postulates the existence of a limited number of innate, evolutionary-relevant fears, while emphasising conditioning modes of onset for evolutionary-neutral fears. Recent retrospective and longitudinal studies have tested predictions from the non-associative model. In general, findings support non-associative hypotheses and are difficult to reconcile with neo-conditioning explanations of fear acquisition. These data suggest that four pathways to fear may provide the most parsimonious theory of fear etiology. The theoretical and practical implications of adding a fourth, non-associative path to Rachman's (Behav. Res. Ther. (1977) 15, 375-387) three 'associative' pathways are discussed. Unresolved issues requiring further investigation are considered.

Dishabituation processes in height fear and dental fear: an indirect test of the non-associative model of fear acquisition

The fear dishabituation hypothesis described in the non-associative model of fear acquisition was tested in a longitudinal birth cohort study. Results were consistent with height fear and phobia dishabituation. That is, 're-emergence' of a fear of heights occurred between age 11 and 18 years among individuals who reported higher levels of non-specific stress at age 15. Interestingly, there was no evidence for dental fear dishabituation--a finding consistent with the non-associative model of fear acquisition. Strengths and weaknesses of the study were considered and the results discussed in relation to laboratory-based findings on (dis)habituation.

The genetic basis of human scientific knowledge

The ecologically most significant respect in which humankind now dominates all other terrestrial species is in its scientific understanding and technological manipulation of the world. What psychological adaptation underlies this seemingly discontinuous development? There is reason to believe that natural selection has endowed the perceptual/representational systems not only of humans but also of other perceptually and cognitively advanced animals with an implicit knowledge of pervasive and enduring properties of the world. Perhaps especially in the human species, natural selection has, in addition, favoured a heightened degree of voluntary access to the representational machinery embodying this implicit wisdom, thus facilitating the realistic mental simulation of possible actions in the world before taking the risk of carrying them out physically. This, together with the emergence of an unprecedented motivation toward understanding, seems to have enabled some human individuals to use 'thought experiments' to convert more and more of the implicit knowledge that we all share into a self-consistent set of explicit scientific laws. Although knowledge of the world must ultimately come from the world, as empiricists claim, it can in this way come through one's genes as well as through one's own direct perceptual interactions with the world.