Distractor inhibition predicts individual differences in the attentional blink

Abstract

Background: The attentional blink (AB) refers to humans' impaired ability to detect the second of two targets (T2) in a rapid serial visual presentation (RSVP) stream of distractors if it appears within 200-600 ms of the first target (T1). Here we examined whether humans' ability to inhibit distractors in the RSVP stream is a key determinant of individual differences in T1 performance and AB magnitude.

Methodology/principal findings: We presented subjects with RSVP streams (93.3 ms/item) of letters containing white distractors, a red T1 and a green T2. Subjects' ability to suppress distractors was assessed by determining the extent to which their second target performance was primed by a preceding distractor that shared the same identity as T2. Individual subjects' magnitude of T2 priming from this distractor was found to be negatively correlated with their T1 accuracy and positively related to their AB magnitude. In particular, subjects with attenuated ABs showed negative priming (i.e., worse T2 performance when the priming distractor appeared in the RSVP stream compared to when it was absent), whereas those with large ABs displayed positive priming (i.e., better T2 performance when the priming distractor appeared in the RSVP stream compared to when it was absent). Thus, a subject's ability to suppress distractors, as assessed by T2 priming magnitude, predicted both their T1 performance and AB magnitude.

Conclusions/significance: These results confirm that distractor suppression plays a key role in RSVP target selection and support the hypothesis that the AB results, at least in part, from a failure of distractor inhibition.

Figure 1. Experimental task and results.

A) Subjects viewed RSVP streams of letters. Target 1 (T1) was coloured red, Target 2 (T2) green and the distractors white. T2 could appear at Lag4 or 10. In the prime present trials, a distractor (priming distractor, PD) with the same identity as T2 appeared at Lag2. All stimuli had different identities in the prime absent trials. Subjects were required to report T1 and T2 at the end of each RSVP stream. B) Effects of the priming distractor and Lag on T2|T1 accuracy. Errors bars represent standard error of the mean. C) Scatter plot of relationship between the AB (prime absent) and Lag4 distractor priming magnitude (T2|T1 % correct at Lag 4 in prime present trials – T2|T1 % correct at Lag 4 in prime absent trials). D) Scatter plot of relationship between Lag4 distractor priming magnitude and T1 accuracy (prime absent trials).

Figure 2. Priming magnitude in subjects with large and small ABs.

Lag4 and Lag10 priming magnitude (T2|T1 % correct at Lag4/10 in prime present trials – T2|T1 % correct at Lag4/10 in prime absent trials) in the low (15 subs with the lowest AB magnitude: Low AB Mag) and high (15 subs with the highest AB magnitude: High AB Mag) AB magnitude groups. Errors bars represent standard error of the mean.