Combined Effect of Color and Shape on Cognitive Performance

Color and shape are important media for information perception, cognition, judgment, and decision making. However, the combined effects of color and shape on cognitive ability have not been widely investigated. In this paper, the perceptual load paradigm is used to investigate the combined effect on icon cognition. Thirty-four healthy subjects (17 males and 17 females, aged 20–26 years, mean = 24, and SD = 4.51) participated in three behavioral experiments using an in-subject design, in which response time and accuracy data were recorded. In a redesigned behavioral experiment, EEG data were recorded from another 20 healthy subjects (10 males and 10 females, aged 20–26 years, mean = 23, and SD = 4.23). Experiment A used color block, graph, and color graph combination icon as the target stimulus. The results indicated that the combination effect was insignificant at high cognitive load, while the combination effect of color and shape at medium and low cognitive loads promoted icon cognition. In experiment B1, both positive and inverted shapes were used as target stimuli, in which the inverted shapes hid the semantic meaning of the shapes. The results showed that the semantic meaning in the combination effect significantly improved cognitive performance at medium and low cognitive loads. In experiment B2, shapes of different complexity were used as target stimuli. The results showed that reducing shape complexity improved cognitive performance with a single color, but shape complexity had no significant effect on cognitive performance with multiple colors. Experiment C used EEG experiments to verify the results of behavioral experiments. The activation degree of combination icons in the occipital lobe was higher than that of shape icons, indicating that the cognitive mechanism of combination and shape icons was not completely the same. Our study shows that the combined effect of color and shape significantly improves cognitive performance at moderate-to-low cognitive loads, in which color and semantic information play a key role.