Count on arousal: introducing a new method for investigating the effects of emotional valence and arousal on visual search performance

There is a large body of research, indicating that threatening stimuli with evolutionary history are prioritised in visual processing. It has been proposed that all threatening stimuli are prioritised, irrespective of evolutionary age, but it was argued that the method used to produce the results was not suitable for investigating the phenomenon. We present a new visual search task and provide evidence that it is an appropriate tool for future research. In Experiment 1, we investigated how the influence of emotional stimuli on visual search performance varies with valence (negative, positive, and neutral) and arousal (medium and high). Negative valence found to have a greater impact. Furthermore, our results underscore the importance of controlling for arousal. Experiment 2 confirmed these findings and also revealed that negative valence decreases performance by diverting attention away from the task, but arousal can compensate for this by increasing attentional capacity. This mechanism does not seem to be affected by the evolutionary history of the stimulus. In Experiment 3, we reproduced these results using a touchscreen monitor and controlling for variance in low-level visual features. We claim that these results support the notion of preferential processing of threatening cues, regardless of evolutionary origin. However, the level of threat, i.e., how arousing the cue is, has to be taken into account to explain the findings.