Most phobias are focussed on a small number of fear-inducing stimuli (e.g., snakes, spiders). A review of the evidence supporting biological and cognitive explanations of this uneven distribution of phobias suggests that the readiness with which such stimuli become associated with aversive outcomes arises from biases in the processing of information about threatening stimuli rather than from phylogenetically based associative predispositions or “biological preparedness.” This cognitive bias, consisting of a heightened expectation of aversive outcomes following fear-relevant stimuli, generates and maintains (...) robust learned associations between them. Some of the features of such stimuli which determine this expectancy bias are estimates of how dangerous they are, the semiotic similarity between them and their aversive outcomes, and the degree of prior fear they elicit. Ontogenetic and cultural factors influence these features of fear-relevant stimuli and are hence important in determining expectancy bias. The available evidence does not exclude the possibility that both expectancy biases and specific evolved predispositions coexist, but the former can explain a number of important findings that the latter cannot. (shrink)

Recent studies of spider phobia have indicated thatfearof spiders is closely associated with the disease-avoidance response of disgust. It is argued that the disgust-relevant status of the spider resulted from its association with disease and illness in European cultures from the tenth century onward. The development of the association between spiders and illness appears to be linked to the many devastating and inexplicable epidemics that struck Europe from the Middle Ages onwards, when the spider was a suitable displaced target for (...) the anxieties caused by these epidemics. Such factors suggest that the pervasive fear of spiders that is commonly found in many Western societies may have cultural rather than biological origins, and may be restricted to Europeans and their descendants. (shrink)

A proper evaluation of the biological significance of Pavlovian conditioning requires consideration of performance mechanisms. Domjan et al.'s definition of net benefit is simplistic, and their model promotes convergence in behaviour, ignoring the possibility of innovation.

A series of arguments are presented by De Jong & Merckelbach which suggest that biological preparedness has been received significantly less critically than it should have been. I agree fully with their assessment. Cuthbert raises four questions about the applicability of the expectancy bias hypothesis to selective associations in human conditioning. This response argues that none of these four examples is necessarily problematic for the hypothesis.