EXPRESS: Why do location-based preference effects occur within decision making? Evidence from the magician’s force

Preference research has shown that humans have a bias towards items located in the middle of the visual field and a number of theories have been suggested to explain the phenomenon. The conjuring trick known as the placement force not only exploits this central bias but also shows that the preference is subtly biased to the right of centre. We used the force, together with eye tracking, to test the different theories. In a single experiment, four face-down playing cards were presented on a table in a horizontal row. Participants (n = 137) were asked to select one by pushing it forward. Results replicated the basic force effect showing that 52% of participants chose the middle right card. Eye tracking measures revealed that when participants fixated the cards, more time was spent looking at the two centrally located cards. However, this attentional bias did not predict the card they chose. Furthermore, individuals who were more reflective decision makers (as measured with the Cognitive Reflection Test) were no less susceptible to the force, nor were individuals who spent more time deliberating about their decision or those who examined more alternatives. The results do not support the view that central bias effects result from cognitive decision heuristics nor attentional biases. Instead, participants chose options that required the least physical effort. This supports the reachability hypothesis.