Is a Snake Scarier Than a Gun? The Ontogenetic-Phylogenetic Dispute From a New Perspective: The Role of Arousal

Organisms have to be able to detect threats in order to activate their defensive mechanisms. Previous research has suggested that evolutionary old stimuli have an advantage during visual processing. Recent evidence indicates that negative emotional stimuli have a greater effect on the cognitive system regardless of evolutionary relevance. We suggest that the arousal level of the stimuli could account for these mixed results. We investigated how visual processing is influenced by evolutionary relevant and modern threatening emotional stimuli. Furthermore, we manipulated the level of arousal (medium, high) of the threatening cues. Participants performed an odd-one-out visual search task, in which the target was always a threatening picture. Our results showed that participants detected modern threatening targets faster than they did evolutionary relevant ones. However, the interaction with arousal revealed that this was only true at high-arousal level; there was no difference between evolutionary relevant and modern threatening targets when presented at medium-arousal level. To our knowledge, to date this is one of the first studies to show the importance of the arousal level of stimuli. On the basis of our findings, we suggest that increasing arousal level only heightens visual search performance with modern threatening cues.