| It is generally believed that attentional resources are limited and the processing of important information under divided attention condition will be affected.However,recent studies on the attentional boost effect have revealed another relationship between attention and memory.Attentional boost effect(ABE)refers to the phenomenon that when performing a secondary task of target detection in the study phase,the processing of the background items presented with target will be enhanced,producing a memory advantage accompanying the target items.Studies have found that ABE is relatively stable under various conditions.This study mainly explored the influence of encode intentionality on attentional boost effect.Experiment 1 was based on the classical study of attentional boost effect,and manipulated the encode intentionality of participants in the study phase through instruction,forming two conditions: intentional encode and incidental encode conditions.Participants were instructed to memorize a series of words while performing target detection task under the intentional encode condition,while other participants were instructed to perform target detection task only and ignore the words presented on the screen under the incidental encode condition.Subsequently,an R/K judgment was added after the recognition judgment in the test phase to explore the different effects of target detection on recollection and familiarity in recognition memory under different encode intentionality conditions.The results showed that ABE was produced under both two encode conditions,but the effect of target detection on recollection and familiarity in recognition memory was different.Specifically,under intentional encode condition,the hit rate of target words was significantly higher than that of distractor words in remember,but there was no difference between target and distractor in know;under incidental encode condition,there was no difference between target and distractor in remember,but target was significantly higher than distractor in know.To investigate whether the attentional boost effect is affected by the presenting time of detect stimuli and background stimuli during the study phase under incidental encode condition,Experiment 2 was based on Experiment 1,extended the presenting time of detect stimuli to the same as that of background stimuli,that is 500 ms.The results showed that ABE was still produced under both two encode conditions,but the effect of target detection on the recollection and familiarity in recognition under the incidental encode condition was similar as that under the intentional encode condition,that is,a facilitation effect on remember response but no difference on know response.In order to further explore whether the attentional boost effect under the incidental encode condition stem from the excessive presenting time of background stimuli in the study phase,which led to redundant attentional resources spill over to task-irrelevant background items,Experiment 3 was based on Experiment 2,shortened the presenting time of detect stimuli and background stimuli to 200 ms.The results showed that the attentional boost effect in the intentional encode condition were consistent with the previous two experiments,while this effect in the incidental encode condition was disappeared.Combining the results of the above all experiments,this study drew the following conclusions: the attentional boost effect can be produced even under incidental encode condition,but its mechanism is different from that under intentional encode condition:target detection mainly promotes recall recognition that depends on the memory of item details under intention encode condition,and is not affected by the presenting time of the detection stimuli,showing relative stability;the mechanism of target detection is affected by the allocation of attention resource and study-test item perceptual fluency under incidental encode condition,resulting different characteristics. |
