Change detection in complex scenes: hemispheric contribution and the role of perceptual and semantic factors.

The perceptual salience and semantic relevance of objects for the meaning of a scene were evaluated with multiple criteria and then manipulated in a change-detection experiment that used an original combination of one-shot and tachistoscopic divided-visual-field paradigms to study behavioural hemispheric asymmetry. Coloured drawings that depicted meaningful situations were presented centrally and very briefly (120 ms) and only the changes were lateralised by adding an object in the right or in the left visual hemifield. High salience and high relevance improved both response times (RTs) and accuracy, although the overall contribution of salience was greater than that of relevance. Moreover, only for low-salience changes did relevance affect speed. RTs were shorter when a change occurred in the left visual hemifield, suggesting a right-hemisphere advantage for detection of visual change. Also, men responded faster than women. The theoretical and methodological implications are discussed.