Abstract: By using the single-probe change detection paradigm and a divided-attention procedure, two experiments were conducted in the present study to investigate the effects of feature dimension and attentional level on the representation of objects in visual working memory. Fourteen undergraduate volunteers participated in the first experiment, which was designed to examine whether features within the same dimension could be represented based on object, and whether such kind of representation was influenced by attentional level. In the second experiment, eight shapes and colors were combined into objects consisting of features from different dimensions. The representation form of such objects and the role of attention were examined. The results showed: (1) Objects defined by features from the same dimension were stored automatically with single feature as unit in visual working memory even in single probe condition. (2) Objects composed of features within different dimensions could be represented in integrated object form which demanded engagement of focused attention. (3) The storage of integrated information during perception stage in working memory also consumed attention resource

Key words: attentional level, visual working memory, representation of object, binding problem