Are natural threats superior threats?

Abstract

Threat superiority effects describe the reaction time advantage for locating threatening objects in a visual search paradigm, compared to locating visually similar non-threatening objects. They are widely reported for threats of both natural (snakes and spiders) and man-made (guns and knives) origins. Across two experiments, the current study contrasts threat superiority effects for natural and man-made targets. When targets are not depicted held, snakes and spiders tended to exhibit larger threat superiority effects, and were searched for with additional caution, than were guns and knives. When snakes and spiders were depicted held and weapons wielded, systematic differences between the natural and man-made threats disappeared. This means the advantage for threats of natural origin observed when all targets were depicted not held may be attributable to differences in animation – snakes and spiders are alive and may strike at any time if in your vicinity, whereas a weapon can only inflict harm if wielded. From these data there is no evidence that evolved visual sensitivities to the basic shapes of venomous animals support faster detection and response times to these animals than can occur to targets such as guns and knives, whose shapes must be learned. The selection pressures that led to the evolution of such sensitivities (observable even in infancy) may therefore lie in protecting young children and babies from envenomation, before they even have the cognitive capacity to understand the dangers that snakes and spiders pose.