In order to figure out if our ability to spot — and be distracted by — stimuli had an evolutionary biology reason or was simply learned, researchers checked to see if people were more distracted from a task by spiders or by Doctor Who.
The things we are afraid of get our notice more easily than things we view neutrally. One theory is that our biology brings are attention most quickly to threats. And if you're an arachnophobe, spiders are a threat. Another theory is simply that our attention is grabbed by whatever in the room has the most relevance to us — i.e. that it's something we learn based on our experiences.
In order to test these theories, researchers performed attention tests with distractors. One was spiders and one was something that we could not have encountered in nature: a Gallifreyen who goes by the name "The Doctor."
In the very geekily titled "But what about the Empress of Racnoss? The allocation of attention to spiders and Doctor Who in a visual search task is predicted by fear and expertise." published in Emotion in 2011, researchers asked participants to look at a grid of photos and answer whether or not a horse was among the photos.
The participants were divided into three groups: Whovians, Whovian arachnophobes, and people with no strong feelings on either. Mixed in with the photos of horses, spiders, and the Doctor were photos from Blue Heelers and fish. The amount of distraction was measured by reaction time.
If we are hardwired to see threats, spiders should have been more distracting to all three groups. Instead, Whovian group was more distracted by Doctor Who than by spiders:
The outcome, as described by the researchers was:
The experiment demonstrated that attentional allocation correlates with, and, moreover, can be predicted from, stimulus relevance. Hierarchical linear models using the Doctor Who expertise questionnaire and the spider apprehension questionnaire showed evidence of a double dissociation: Scores on the Doctor Who questionnaire were positively correlated with the interference gen- erated by images related to Doctor Who but not interference generated by pictures of spiders; conversely, scores on the spider apprehension questionnaire were strongly correlated with interfer- ence generated by pictures of spiders but not with interference generated by Doctor-Who-related images. This double dissociation was also seen when looking at different groups of participants: Participants who had a fear of spiders and who watched Doctor Who showed a stronger attentional bias for pictures of spiders than for images related to Doctor Who, whereas participants who watched Doctor Who and had no fear of spiders had a stronger attentional bias for images related to Doctor Who than for pictures of spiders. This evidence strongly suggests that attentional biases are not threat/anxiety specific but apply to all stimuli of sufficient relevance, positive or negative.
The conclusion was that personal relevance impacts attention far more than the threat level. However, the researchers did not check for fictional giant alien spiders from Doctor Who, so “Where this leaves the Empress of Racnoss, we are unsure.”