Task-switching mediates direct interference of intertarget distractors in the attentional blink
26.549, Saturday, 17-May, 2:45 pm - 6:45 pm, Pavilion
Alexia Ptito1, Benoit Brisson2; 1Université de Montréal (Psychologie), 2Université du Québec à Trois-Rivières (Psychologie)
The attentional blink (AB) refers to the difficulty in reporting a second target (T2) when presented shortly after a first target (T1) in a rapid serial visual presentation (RSVP) of distractors. There is an ongoing debate as to the role of intertarget distractors in the AB. Some studies have proposed that intertarget distractors can only modulate the AB indirectly by affecting processing of T1. Others have suggested that intertarget distractors can modulate the AB directly, without affecting T1 processing. The goal of the present study was to investigate distractor-based interference in the AB by recording the P3 component of the event-related potential to both targets while varying intertarget events and task switching between targets. An intervening distractor was presented at lag 1 (T1 + 1), at lag 2 (T1 + 2), or at neither of these two lags (no distractor). T2 was always presented during the AB (at lag 3), and was always the last item in the RSVP stream. In two experiments, the P3 to T1 was attenuated in the T1+1 condition compared to the two other distractor conditions, demonstrating that the intertarget distractor interfered with T1 processing only if presented at lag 1. In absence of a task switch (Experiment 1), the P3 to T2, obtained by subtracting T1-only trials from T1+T2 trials, was delayed in both the T1+1 and T1+2 conditions compared to the no distractor condition. In the presence of a task switch (Experiment 2), the P3 to T2 was delayed only in the T1+1 condition. Results demonstrate that intertarget distractors can modulate the AB directly without affecting T1 processing, but only in absence of a task switch between targets. Implications for extant models of the AB are discussed.