Impaired visual working memory capacity in case of motion direction and color-shape feature binding

It has been proposed that visual working memory can hold a set of approximately four objects and the number of remembered objects is the same whether the objects have one relevant single feature, or two, or even four (Luck & Vogel; Wheeler & Treisman). Although the actual visual images have color shape and motion features, traditional change detection tasks were mainly related to only color and shape. This study using dynamic color random dots dealt with motion direction and color shape equally and then tested previous proposals. The capacity significantly decreased when motion features were added, that is to say, the performance in motion and both color and shape binding conditions was worse than in a single feature condition, unlike in color and shape binding condition. Our results suggest that motion feature competes for color shape feature, therefore visual working memory capacity for multidimensional objects is impaired contrary to a widely held view