Abstract
Historically, the pervading assumption among sensory psychologists has been that attention and awareness are intimately linked, if not identical, processes. However, a number of recent authors have argued that these are two distinct processes, with different functions and underlying neuronal mechanisms. If this position were correct, we should be able to dissociate the effects of attention and awareness with some experimental manipulation. Furthermore, we might expect extreme cases of dissociation, such as when attention and awareness have opposing effects on some task performance and its underlying neuronal activity. In the last decade, a number of findings have been taken as support for the notion that attention and awareness are distinct cognitive processes. In our symposium, we will review some of these results and introduce psychophysical methods to manipulate top-down attention and awareness independently. Throughout the symposium, we showcase the successful application of these methods to human psychophysics, fMRI and EEG as well as monkey electrophysiology.
First, Nao Tsuchiya will set the stage for the symposium by offering a brief review of recent psychophysical studies that support the idea of awareness without attention as well as attention without awareness. After discussing some of the methodological limitations of these approaches, Jeroen VanBoxtel will show direct evidence that attention and awareness can result in opposite effects for the formation of afterimages. Takeo Watanabe's behavioral paradigm will demonstrate that subthreshold motion can be more distracting than suprathreshold motion. He will go on to show the neuronal substrate of this counter-intuitive finding with fMRI. Joel Voss will describe how perceptual recognition memory can occur without awareness following manipulations of attention, and how these effects result from changes in the fluency of neural processing in visual cortex measured by EEG. Finally, Alexander Maier will link these results in the humans studies to neuronal recordings in monkeys, where the attentional state and the visibility of a stimulus are manipulated independently in order to study the neuronal basis of each.
A major theme of our symposium is that emerging evidence supports the notion that attention and awareness are two distinctive neuronal processes. Throughout the symposium, we will discuss how dissociative paradigms can lead to new progress in the quest for the neuronal processes underlying attention and awareness. We emphasize that it is important to separate out the effects of attention from the effects of awareness. Our symposium would benefit most vision scientists, interested in visual attention or visual awareness because the methodologies we discuss would inform them of paradigms that can dissociate attention from awareness. Given the novelty of these findings, our symposium will cover a terrain that remains largely untouched by the main program.