CAJ | 학술논문

使用事件相关电位技术，采用变化觉察范式，以双色块和单色块为刺激材料，通过两个实验探讨了多特征刺激在视觉工作记忆中的存储模式。实验1通过对双色块和单色块的比较来考察特征数量对视觉工作记忆资源分配的影响，通过操控双色方块的变化幅度来考察精度需求对资源分配的影响。结果发现，特征数量的增加诱发了更强的对侧延迟活动（CDA），而精度需求的提高并没有引起对侧延迟活动上的差异，却诱发了指示自上而下的控制的晚期正成分（LPC）的增强。实验2通过在测验阶段加入指示可能变化的部分的提示符，发现提示符并未能促进变化觉察的行为反应。整个研究表明，特征数量影响视觉工作记忆资源的分配，而精度需求并不起作用，同时多特征刺激在视觉工作记忆中的存储单位并不是单个的独立特征，而是整合的客体。
사용사건상관전위기술，채용변화각찰범식，이쌍색괴화단색괴위자격재료，통과량개실험탐토료다특정자격재시각공작기억중적존저모식。실험1통과대쌍색괴화단색괴적비교래고찰특정수량대시각공작기억자원분배적영향，통과조공쌍색방괴적변화폭도래고찰정도수구대자원분배적영향。결과발현，특정수량적증가유발료경강적대측연지활동（CDA），이정도수구적제고병몰유인기대측연지활동상적차이，각유발료지시자상이하적공제적만기정성분（LPC）적증강。실험2통과재측험계단가입지시가능변화적부분적제시부，발현제시부병미능촉진변화각찰적행위반응。정개연구표명，특정수량영향시각공작기억자원적분배，이정도수구병불기작용，동시다특정자격재시각공작기억중적존저단위병불시단개적독립특정，이시정합적객체。
Visual working memory （VWM）is a temporary buffer that maintains a limited set of items （i.e., 3-4 objects） in an “online” state. Luck and Vogel （1997） demonstrated that the capacity was limited by the number of the integrated objects, but not by the number of the individual features. However, with the conjunction of homogenous features served as memory materials, follow-up studies showed that the subjects could retain fewer items than single-feature objects. Some researchers considered that the lower accuracy for conjunction of homogenous features may result from the difference of precision requirement, which was manipulated by the similarity between sample and test array. However, some experiment results showed that higher precision could only affect the accuracy of change detection task, but not the capacity. In present study, we carried out two experiments using change detection paradigm to examine the storage mechanism of multi-feature objects in VWM. In experiment 1, multi-feature and single-feature objects were defined by double-color objects and single-color objects, respectively. To manipulate the precision requirement, we further divide double-color objects into two conditions, that is, a single-change condition in which only one of the two colors changed （high-precision）, and a double-change condition in which both colors changed （low-precision）. In experiment 2, we focused on the single-change condition, and investigated the units of storage in VWM by manipulating weather there was an arrow indicating the changed color in the test phase. The result would further explain whether the storage mechanism of multi-feature objects is in an integrated manner or in an individual features manner. In experiment 1, we first compared the results of double-color objects and single-color objects to assess the influence of the feature number on the allocation of VWM capacity. Behavioral results showed that double-color objects were responded less accurately than single-color objects. The ERPs results showed that the amplitude of CDA for double-color objects was significantly higher than for single-color objects. Second, we compared the double-change condition and single-change condition to explore the effect of precision requirement. Lower accuracy was found for the single-change condition. CDA amplitudes did not differ between the two conditions. Instead, the amplitude of LPC for the single-change condition was more positive than for the double-change condition. In experiment 2, the accuracy was not modulated by weather there was an arrow or not. These results reveal that the number of features, but not the precision requirement, has an effect on the allocation of VWM capacity. And the units that limit our VWM capacity are the integrated objects instead of the individual features.