Cortical dynamics of negative afterimages: Spatial properties of the inducer

Types of attention matter for awareness: a study with color afterimages

It has been argued that attention and awareness might oppose each other given that attending to an adapting stimulus weakens its afterimage. We argue instead that the type of attention guided by spatial extent and perceptual levels is critical and might result in differences in awareness using afterimages. Participants performed a central task with small, large, local, or global letters and a blue square as an adapting stimulus in three experiments and indicated the onset and offset of the afterimage. We found that increases in the spatial spread of attention resulted in the decrease of afterimage duration. In terms of levels of processing, global processing produced larger afterimage durations with stimuli controlled for spatial extent. The results suggest that focused or distributed attention produce different effects on awareness, possibly through their differential interactions with polarity dependent and independent processes involved in the formation of color afterimages.

Focused and distributed attention

Recent studies on attention have emphasized distinctions between focused and distributed attention. Distributed attention has been shown to play a key role in obtaining statistical information or processing global aspects of a scene. In addition to differences in information processing, focused and distributed attention differ in terms of the way they interact with emotions. We review findings that indicate close relationship between focused attention and sad emotions as well as distributed attention and happy emotions. Given the potentially close relationship between attention and consciousness, these two types of attention may differ in terms of processes leading to awareness. We review different positions on the relationship between attention and consciousness and arguments for the existence of opposition between attention and awareness that have been made based on findings with color afterimages. We discuss our studies on attention and afterimages indicating the close linkage between different types of attention and awareness as indicated by differences in the strength of afterimages based on the type of attention deployed.