Mean proportion of hits [P(H)], proportion of false alarms [P(FA)], and d' scores in the LAT administered in Experiment 1.

Performance was assessed by calculating d', an index of perceptual sensitivity based on signal detection theory. For each perceptual discrimination, one of the responses (e.g., ‘1') was treated as ‘signal present’ and the other response (e.g., ‘3’) as ‘signal absent’. Thus, responding with ‘1’ to targets at position 1 were labelled as ‘hits’ whereas responding with ‘1’ to targets at position ‘3’ were recorded as false alarms. The same procedure was applied in the case of ‘right’ targets at positions 2 and 4. In this way, we obtained the probability of hits – P(H) – and false alarms – P(FA) – to calculate d'. One-sample t-tests indicated that sensitivity scores did not differ from chance (d' = 0).