Abstract
Cultural differences in the way adults from East Asian and Western Caucasian societies perceive and attend to visual stimuli have been consistently demonstrated in recent years. Westerners display an analytical processing style, attending to focal objects and their features. By contrast, Easterners show interest in context and relationships between objects, which is indicative of holistic processing. Although much behavioural evidence supports the existence of these cultural processing styles, the neural mechanisms underlying such perceptual biases are poorly understood. The combination of Navon figures, which contain both global and local elements, and the measurement of neural adaptation constitute an ideal way to probe this issue. Here we exploited a novel neural adaptation single-trial EEG method and recorded electrophysiological signals from British and Chinese observers while viewing two sequentially presented Navon Shapes. To control for potential confounds related to Westerners' familiarity with letters from the Roman alphabet, we constructed Navon figures made from geometric shapes. Additionally, to control for potential attentional biases and eye movements, observers performed a colour change detection task on a central fixation. In each trial, participants sequentially viewed a Navon shape followed a further shape from one of four categories: the same, local changes, global changes, local and global changes. Both groups displayed most adaptation at P1 and N170 when neither element was changed and most when both were altered. However, the critical results come from the local or global change conditions. By contrast to Westerners, Easterners showed no sensitivity to local changes, with as much adaptation occurring as when no elements were changed. This suggests that default neural coding of local and global properties occurs very early in visual processing and differs markedly between cultures, with inefficient coding of local elements in Easterners. Such visual tuning could underlie more complex behavioural differences observed across human populations.