The effect of snake and spider images on the oculomotor system : an eye-tracking study

Previous studies have demonstrated attentional bias to emotional images, including images of snakes and spiders. However, researchers are yet to compare attentional bias to snake and spider images in an eye-tracking study. Furthermore, there is evidence that suggests that primates have a predisposition to detect snakes, as they are evolutionarily relevant. The aim of this study was to assess attentional bias to spider and snake images via eye-tracking, and to see if such images are capable of inducing Pavlovian conditioning. Twenty-five participants underwent two dot probe tasks. It was hypothesised that emotional images would elicit faster oculomotor responses, that there would be no difference between spider and snake images, that there would be a conditioning effect, and that snakes would elicit a stronger conditioning effect given their ancestral relevance. Instead, results revealed that participants directed their gaze towards neutral images more quickly than emotional images. It is likely that the current study observed a later stage of attentional processing than previous work, which can be explained by the vigilant-avoidant hypothesis. It was also found that spider images elicited a greater emotional response than snake images. Lastly, Pavlovian conditioning to coloured shapes paired with the images was not observed.