Every day, people perceive other people performing interactive actions. Retaining these actions of human agents in working memory (WM) plays a pivotal role in a normal social life. However, whether the semantic knowledge embedded in the interactive actions has a pervasive impact on the storage of the actions in WM remains unknown. In the current study, we investigated two opposing hypotheses: (a) that WM stores the interactions individually (the individual-storage hypothesis) and (b) that WM stores the interactions as chunks (the chunk-storage hypothesis). We required participants to memorize a set of individual actions while ignoring the underlying social interactions. We found that although the social-interaction aspect was task irrelevant, the interactive actions were stored in WM as chunks that were not affected by memory load (Experiments 1 and 2); however, inverting the human actions vertically abolished this chunking effect (Experiment 3). These results suggest that WM automatically and efficiently used semantic knowledge about interactive actions to store them and support the chunk-storage hypothesis.

Visual working memory (VWM) maintains and manipulates a limited set of visual objects being actively used in visual processing. To explore whether and how the fine detailed information is stored in VWM, four experiments have been conducted while recording the contralateral delay activity (CDA), an event-related potential difference wave that reflects the information maintenance in VWM. The type of the remembered information was manipulated by adopting simple objects and complex objects as materials. We found the amplitude of CDA was modulated by object complexity: as the set size of memory array rose from 2 to 4, the amplitude of CDA stopped increasing for maintaining complex objects with detailed information, while continued increasing for storing highly discriminable simple objects. These results suggest that VWM can store the fine detailed information; however it can not store all the fine detailed information from 4 complex objects. It implies that the capacity of VWM is not only characterized by a fixed number of objects, there is at least one stage influenced by the detailed information contained in the objects. These results are further discussed within a two-stage storing model of VWM: different types of perceptual information (highly discriminable features and fine detailed features) are maintained in VWM via two distinctive mechanisms.

Most gestural interaction studies on gesture elicitation have focused on hand gestures, and few have considered the involvement of other body parts. Moreover, most of the relevant studies used the frequency of the proposed gesture as the main index, and the participants were not familiar with the design space. In this study, we developed a gesture set that includes hand and non-hand gestures by combining the indices of gesture frequency, subjective ratings, and physiological risk ratings. We first collected candidate gestures in Experiment 1 through a user-defined method by requiring participants to perform gestures of their choice for 15 most commonly used commands, without any body part limitations. In Experiment 2, a new group of participants evaluated the representative gestures obtained in Experiment 1. We finally obtained a gesture set that included gestures made with the hands and other body parts. Three user characteristics were exhibited in this set: a preference for one-handed movements, a preference for gestures with social meaning, and a preference for dynamic gestures over static gestures.