The Effect Mechanism Of Non-targets Upon Attentional Blink In RSVP

In the rapid serial visual presentation, when T2 (the fist target) is presented within 200-500ms after T1 is selected (the second target), T2 will suffer a recognition difficulty. This phenomenon is called attentional blink (AB).The phenomenon of attentional blink was found in those studies about temporal dimention of attention.for two decades, many theories and models have been proposed to explain the phenomenon of AB, such as two-stages model, central-interference theory, temporary loss of control (TLC) model and the delayed engagement of attention hypothesis etc.The two-stages model of Chun and Potter assumed that the AB deficit is said to occur when the second target arrives while the resources at a high-level stage are preempted by the first target, and is delayed into the second stage while resorted in the first stage where its representation is vulnerable to overwritten. Jolicoeur and Dell Acqua's PRP model is similarly predicated on resource limitations leading to a bottleneck at a late processing stage. The theories mentioned above can be generalized as the bottleneck theory which emphasizes the limited capacity of high-level central processing cause the AB. In rencent years, as those new models, such as the temporary loss of control and the delayed engagement of attention,were emerged, the relationship between targets and non-targets came into further consideration.In the early theory of distractor inhibitory hypothesis, AB is described as the result of inhibitory effect triggered by non-targets. The temporary loss of control make the critical assumption that, while the central processor continues to issue appropriate control signals, the system's configuration cannot be altered exogenously by the leading distractors in the RSVP stream. Upon arrival of the first target, however, the central processor becomes engaged in stimulus processing and response planning, and can no longer issue the required control signals. An interruption in the functioning of the control mechanism corresponds to a lapse of attention. The delayed reengagement of attention explain the AB in terms of the dynamics of processes of attentional selection. The difficulty in encoding a trailing target would then stem from the difficulty of rapidly reengaging attention shortly after attention was disengaged following the selection of Tl.According to this, the non-targets intervening between T1 and T2 act as a delay in AB.In the present study, we examine the nature of AB from the standpoint of non-targets in RSVP. In experiment 1, it will result in the reduction of AB effect when delete the non-targets following T2 and just make them slightly shifting away from the central places where the targets are presented. The results demonstrate the necessity of masked T2 to the occurrence of AB and exclude the distraction effect elicited from the distractors. In experiment 2, we find that although attenuating the forward-masking of T2 improves the correct rates of T2 recognition in all levels of SOA, the J-Shaped reaction pattern remains similar to the base line and AB still appears. When there is no any non-targets following T1, the correct rates of T2 recognition decreases significantly. The result seems that the masking to T1 is also one of the essential conditions for AB. However, in experiment 3,even if there is no any non-targets following T1, the blink was also observed when increasing the processing difficulty of T1.And further more, to increase the processing difficulty of T1 will produce more significant effect of AB than the base line if there are non-targets intervening between T1 and T2.