关键词: 视觉工作记忆, 内部注意, 内部注意选择, 回溯线索范式, 回溯线索效应

Abstract: When the external input disappears, the information stably stored in the visual working memory (VWM) is still affected by the internal attention. The present study systematically reviews the internal attentional selection in VWM by analyzing and summarizing current articles in this field. The main tools in this field are the retro-cue paradigm and the task-switch procedure. The typical feature of first paradigm is to present a retrospective cue during the retention of VWM, telling the subject that the item pointed to by the cue is most relevant to the current task. Retro-cue can manipulate internal attention directly, so this paradigm is more commonly used than task-switch procedure. The effects of internal attentional selection can be detected by behavioral experimental methods, and the specific process of change and internal state of the selection can be explored by neuroscience experimental methods. The effect of internal attentional selection in VWM is that the selected items gain advantages, while the unselected items may be damaged. This effect was reflected in the experimental results as the retro-cue effect. The selected item have an impact on subsequent search tasks and can offset the damage caused by the interference. A focus of internal attention can also improve load effects and prevent information from declining over time.The existence of damage is still controversial, through the summary we found that it can be affected by a variety of factors., including the proportion of invalid cue, the load, the difficulty of the memory materials and so on. In the end, we conclude that whether damage occurs or not, may essentially follow a "subjective optimal strategy under resource limitation." That is to say, based on available resources,?there is a trade-off between performance and convenience. This article also summarizes four characteristics of the internal attentional selection in VWM.The time course of it is that the priority effect takes at least 50ms, and the optimal stability requires about 400ms. Both objects and features can be manipulated by internal attention. Internal attention can have an advantageous impact on more than one item at the same time. And this priority effect does not require sustained internal attention to maintain it. Among the theoretical mechanisms of internal attentional selection in VWM, the Three-Embedded-Components Model of Working Memory is the most consistent. Because under this theory, the participants can flexibly choose whether to remove unselected items or not. In addition, by summarizing the neuroscience articles in this field, we find that the neural mechanisms behind this are mainly involved the occipital visual cortex, posterior parietal cortex (PPC), prefrontal cortex (PFC), and cortical striatum. Among them, PPC and PFC play an important role in extracting information from VWM to FoA. Some suggestions for future research are proposed. The relationship between stored items in VWM can also have a significant impact on internal attentional selection in VWM. Meanwhile, we should explore whether the enhanced and suppressed operation of internal attention share the same resource. And it should be probed that whether it is difficult or even impossible to autonomously separate the internal attention extraction and the behavioral response.

Key words: visual working memory, internal attention, internal attentional selection, retro-cue paradigm, retro-cue effect