A critical appraisal of processing visual threat

The central issue in this thesis is how humans process visual threat. Rapid threat processing is proposed to be a valuable asset in terms of survival. Three main
hypotheses were tested: (1) there is an association between the motor actions and threat processing, namely threat is responded to faster by avoiding it than approaching it. (2) Threat restricts the scope of attentional focus. (3) Threat is detected automatically and faster than non-threats. To control for possible confounding stimuli factors, photographic images of threatening cats, threatening
dogs, non-threatening cats and non-threatening cats were used throughout three experimental chapters. To test whether threat processing is task-dependent,responses to threat were examined in three tasks: animal classification tasks (to judge whether the target images are cat images or dog images), threat classification tasks (to judge whether the target images are threatening or non-threatening) and speeded search tasks (to judge whether all the images are from the same category or there is one odd-ball image).

The consistent findings are: evidence from the animal classification tasks shows that responses to threatening stimuli were slower than those to non-threatening stimuli, however, this effect could be due to the familiarity of the animals (the non-threatening animals are more familiar to participants and easier to be classified) rather than stimuli valence. Evidence from the search tasks shows that threatening stimuli were detected faster than the non-threatening stimuli, however, by carefully controlling the stimuli factors, the magnitude of the threat detection advantage decreased. Overall, no robust evidence was uncovered that indicates a special sensitivity towards visual threat. The so-called threat effects may be in fact due to other factors, such as low level perceptual features of the stimuli and task requirements.