The Psychological And Neural Mechanisms Of Attentional Blink

Attentional blink(AB)pertains to the performance of participants with a severe decline in identifying the second target(T2)presented after the first target(T1)reported correctly within 200 to 500 ms in a rapid serial visual presentation.The existing theories typically attributed AB to an extended processing of the T1(the so-called T1-based theories),or an inadvertent distractor processing(the so-called distractor-based theories).The study 1and 2 explored the role of distractors and T1 in AB based on distractor-based and T1-based theories,respectively.In Study I,the impact of distractors on AB was explored by manipulating the presence or absence of the distractor(D1)immediately after T1.The results indicated that AB was significantly reduced when D1 was absent.Electroencephalogram(EEG)analysis revealed that the amplitudes of T1-evoked P3 a,N3 and P3 b were reduced and the peak latency of P3 a was delayed when D1 was present.Furthermore,D1 interfered with the amplitude of P3 b in T2 within the AB time window,but not outside the AB time window.The single-trial analysis demonstrated that the amplitudes of T1-evoked P3 a and T2 P3 b could negatively predict AB within the AB time window,while the amplitude of T1 P3 b could positively predict AB.However,the amplitude of N3 could not predict AB.Only the P3 b amplitude of T2 can negatively predict AB while outside the AB time window.Additionally,the time-frequency and multivariate pattern analysis(MVPA)of timefrequency data showed that the presence of D1 interfered with the power of the anterior theta oscillations.These findings suggest that the presence of D1 interferes with the attentional enhancement to T1,thus further reducing the amount of resources available to encode T1 and T2 within the AB time window.In Study 2,the effects of manipulating response congruency between T1 and T2 on the AB were investigated.Results from the EEG analysis showed that the response inconsistency condition elicited a greater P3 b component during AB compared to the response congruency condition.Additionally,MVPA in the time domain revealed that inter-target response congruence could be distinguished with more than random odds during late processing of Target 2.Furthermore,time-frequency analysis revealed that stronger delta oscillations were induced when responses were inconsistent.Taken together,these findings suggest that targets compete with each other for limited processing resources during AB,and that this competition is reduced when inter-target responses are congruent.In both Study 1 and Study 2,it was observed that lower P3 b amplitudes of T2 were present when AB occurred.However,the use of a linear classifier in MVPA was not able to accurately identify the occurrence of AB,indicating the intricate nature of AB.Study3 delved deeper into the neural mechanisms of AB by analyzing brain networks.The results showed that the brain processing patterns were more intricate during AB compared to when it did not occur.Additionally,two opposing microstates were identified,which may represent the processing of distractors and targets,respectively.It was also observed that when there was more processing of the target,the AB was less pronounced.The findings of this study cannot be explained by theories related to AB.It is evident that D1 interferes with the amount of resources available for encoding targets,which is due to its interference with attentional enhancement of T1.T1 competes with T2 for the limited working memory coding resources.The findings of this research indicate that the primary source of AB is the restricted processing capacity in the later stages,and that the quantity of available processing resources is managed by adjustable attentional gating.To reduce competition between targets or to increase the amount of resources available for encoding targets is a significant way to diminish AB.