Exploring the effects of threatening stimuli on visual search performance using different experimental designs

Abstract

The effects of threatening stimuli on visual search performance could be considered well-established findings in experimental psychology. The first studies exploring these effects claimed that threatening cues are highlighted and thus have an advantage in visual processing. This advantage was thought to be a consequence of adaptation during the course of human evolution. That is the development of a defence system (later coined as fear module) to cope with dangers that threatened the survival. Later it was proposed that only threatening cues with evolutionary origin have this advantage in visual processing. However, the studies that arrived at such conclusions only used evolutionary stimuli. Therefore, a new approach emerged using the same, now classical, visual search task (VST) to test modern threatening and non-threatening cues, and to compare the effects of modern threatening stimuli to that of evolutionary relevant ones. These results suggested a relevance superiority effect, i.e. all threatening cues have an advantage in visual processing compared to neutral and other emotional ones. However, the results are often mixed. The VST used in the aforementioned studies had been met with criticism. There is a growing need to find a new alternative to the VST that could account for its flaws. Based on an extensive literature review, the motivation behind the present dissertation was twofold: First, we claim that previous studies exploring the advantaged processing of threatening cues tended to neglect an important emotional variable: arousal level. Second, we did not find a good alternative to the VST. Thus, in the present dissertation we tested the effects of emotional arousal on visual processing using threatening and non-threatening cues. Further, we proposed two alternatives to the VST: The new visual search task was created to eliminate the problems of the VST. While the number finding task is a different approach that opens the possibility to measure cognitive performance. Throughout nine experiments in three studies, we compare the evolutionary relevant and modern threatening cues to non-threatening ones while either manipulating or controlling for the arousal level. We test special groups of firemen and children. Furthermore, we test the reliability and validity of our proposed paradigms. The main result of the dissertation is that arousal does play a crucial role in the visual processing of threatening cues, and therefore, should not be neglected in future studies. Arousal could facilitate visual search performance, and it could also influence the reaction to evolutionary and modern threats differently. Another interesting result is that it seems that not all threatening cues are processed the same way, i.e. some are indeed advantaged. However, we suggest that not evolutionary origin, but other motivational and individual factors discriminate between them. Finally, we showed that the two novel paradigms used to test the aforementioned variables and their effects are also reliable. Thus, the new VST and the number finding task could be used in future studies dealing with visual search or exploring the effects of different cues on visual search performance.