Snakes, spiders, guns, and syringes: how specific are evolutionary constraints on the detection of threatening stimuli?

In three experiments, the efficiency in detecting fear-relevant and fear-irrelevant visual stimuli are compared. A visual search paradigm is used where participants are presented with matrices of different sizes (4 objects/9 objects) and must determine whether all objects are taken from the same category or whether there is a discrepant one. Results from all experiments were consistent with the threat-superiority effect. Participants were quicker when the target was threatening than when it was not. Other indicators confirmed that the detection of threatening targets involves more efficient processes (reduced slopes, absence of position effects). A crucial aspect of these experiments was the comparison of evolutionary-relevant (snakes, spiders, etc.) and modern (guns, syringes, etc.) threats. The threat-superiority effect was repeatedly found for both types of target. Stronger effects were sometimes observed for modern than for evolutionary-relevant threats. The implications for evolutionary explanations of the effect of fear on visual attention are discussed.