The ERP Study Of Attentional Boost Effect

The previous studies of attentional boost effect are based on learning-recognition paradigm, the learning phase includes encoding task and detection task, detection stimulus containing the target and distractor stimuli, participants need to press a key whenever they detected the target item. The result is that memory for study stimuli presented simultaneously with the targets was better than memory for study stimuli that presented simultaneously with the distractors. The researchers believe that the attentional boost effect reflects enhanced visual encoding of the study stimulus consequent to the transient orienting attention to the dual-task target. However, the function of selective attention has targets activation and distractors inhibition, the attentional boost effect may include transient orienting attention and perceptual process to the targets, but also selective attention to reject and inhibit process to distractors. At the same time, a large number of studies focus on the field of scene memory and explicit memory,so we use words as stimuli to study attentional boost effect in explicit and implicit memory. And we want to explore the behavior performance and ERP performance of that and further concern the origin of the attentional boost effect through combining with ERP technology.In the experiment 1, the subjects need complete encoding task and detection task in the study phase. During encoding task, they need read the words in the screen aloud. At the same time, detection stimuli-indicator ("+"、"-"、" ")will appear above the words, they need to detect the target("+") and press the spacebar. The detection stimuli just present 100ms with the words,and the words continued to show 400ms. The study stimuli are divided into the target words(present with "+" together)、the distractor words(present with "-" together)、the blank words(present alone). After study task, they will finish standard recognition task to test explicit memory, and the subjects need to make "Old/New" judgment to the words presented in the screen. The experiment 2 contains study phrase and semantic classification test. The study phrase is similar with the experiment 1. The subjects need to make "word/name" judgment in semantic classification task.The results showed that attentional boost effect existed in explicit memory by behavior and ERP data. Firstly, from behavior level, the correct recognition rate of target words is best significantly, that of distracor words is worst. Secondly, from ERP level, the results support that the attentional boost effect mainly comes from the encoding phase. The target words induced an obvious P200 and P300 effect. The significant difference of targets and distractors、targets and blanks indicate that the attentional boost effect in the explicit memory mainly origin from the selection attention to targets and enhancement perceptual process of words. Next, we study the attentional boost effect in the implicit memory test. The behavior results showed that the response time of target words is significantly shorter than that of distractors, but the ERP results is that P200 and P300 component the distractors induced is more significant than the blank, so we think in unintentional encoding test, the attentional boost effect reflect the inhibitory processing of distractors, therefore enhancing targets’processing. We find the separation between the explicit and implicit memory in attentional boost effect.