Images in the mind: The control of visual object selection by attentional templates

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Our perception of the external visual world and the ways in which we interact with this world are strongly affected by our current expectations, intentions, and our previous experience. Even though we may subjectively feel that our conscious experiences and our actions are primarily determined by the outside world, it is our active mind that shapes what we perceive and how we react to the external world at any given moment. What we become aware of is determined by what we attend to, and what we attend to is determined by "images in the mind" (attentional templates) that guide our attention in line with our goals and preferences. The essential role of the active guiding mind in the control of attention was already highlighted by William James in 1890, but we still know surprisingly little about the nature of attentional templates, and about how these templates determine which object(s) are attended at any time. In the research proposed here, we will apply new experimental procedures and new methodological techniques (including temporally precise measures of electrical brain activity obtained while observers are engaged in attentional selection tasks) to answer some of the fundamental questions that have been debated by experimental psychologists for more than a century. We will investigate how many things we can attend to at any time, and expect to find that the answer suggested by William James ("not easily more than one") may be correct. We will study the adverse consequences of having to simultaneously attend to multiple objects in perception, visual working memory, and action. Are there systematic differences between individuals in their ability to attend to more than one thing at a time? Is this ability age-dependent and can it be improved by training? We will also investigate how the "image in the mind" is organised: Do attentional templates represent integral visual objects, or do they include lists of the visual features that define a current goal object? An answer to this question will have important consequences for current theoretical models of how attention operates. Finally, and very importantly, we will develop new methods to obtain precise measures of the speed of voluntary visual attention shifts: If attention is engaged at a particular location, how fast can it be moved to a new potentially relevant object? And how fast can we change the "image in the mind" if we want to guide our attention to a different object? Our initial results suggest that the top-down guidance of attention can be much faster and is more flexible than is usually believed, and we will now find out whether and under which circumstances this is the case. The question how "images in the mind" control conscious experience and voluntary action is central to theories of selective attention. Finding new answers to this question will have important general theoretical and conceptual implications for attention research. But our research is also important from an applied perspective. A defining feature of life in our technologically advanced society is the attentional competition between multiple sources of information, which result in permanent demands on attentional object selection and choice. New insights into how attentional templates guide what individuals perceive and how they choose to act therefore has obvious practical implications for areas as diverse as education, workplace design, and economic decision making.