What is involved in the consciousness of a conscious, "occurrent" propositional attitude, such as a thought, a sudden conjecture or a conscious decision? And what is the relation of such consciousness to attention? I hope the intrinsic interest of these questions provides sufficient motivation to allow me to start by addressing them. We will not have a full understanding either of consciousness in general, nor of attention in general, until we have answers to these questions. I think there are constitutive (...) features of these states which can be identified by broadly philosophical investigation, and in the early part of this paper I will try to do some of that identification. -/- Beyond the intrinsic interest of the topic, the nature of such conscious attitudes is highly pertinent to a philosophical account of psychological self-knowledge. So I will also say something about the significance of the constitutive features of these conscious attitudes for a philosophical account of how it can be that a thinker has a distinctive kind of knowledge of some of his mental states. The general challenge in this area is to find anything intermediate between the unexceptionable but uninformative, on the one hand, and the absolutely unbelievable on the other. (shrink)

John Campbell investigates how consciousness of the world explains our ability to think about the world; how our ability to think about objects we can see depends on our capacity for conscious visual attention to those things. He illuminates classical problems about thought, reference, and experience by looking at the underlying psychological mechanisms on which conscious attention depends.

Although the mechanics of how the eye works are well understood, debate still exists as to how the complex machinery of the brain interprets neural impulses...

Does attention alter appearance? This critical issue, debated for over a century, remains unsettled. From psychophysical evidence that covert attention affects early vision-it enhances contrast sensitivity and spatial resolution-and from neurophysiological evidence that attention increases the neuronal contrast sensitivity (contrast gain), one could infer that attention changes stimulus appearance. Surprisingly, few studies have directly investigated this issue. Here we developed a psychophysical method to directly assess the phenomenological correlates of attention in humans. We show that attention alters appearance; it boosts (...) the apparent stimulus contrast. These behavioral results are consistent with neurophysiological findings suggesting that attention changes the strength of a stimulus by increasing its 'effective contrast' or salience. (shrink)

According to commonsense psychology, one is conscious of everything that one pays attention to, but one does not pay attention to all the things that one is conscious of. Recent lines of research purport to show that commonsense is mistaken on both of these points: Mack and Rock (1998) tell us that attention is necessary for consciousness, while Kentridge and Heywood (2001) claim that consciousness is not necessary for attention. If these lines of research were successful they would have important (...) implications regarding the prospects of using attention research to inform us about consciousness. The present essay shows that these lines of research are not successful, and that the commonsense picture of the relationship between attention and consciousness can be. (shrink)

First published in 1995, The Visual Brain in Action remains a seminal publication in the cognitive sciences. It presents a model for understanding the visual processing underlying perception and action, proposing a broad distinction within the brain between two kinds of vision: conscious perception and unconscious 'online' vision. It argues that each kind of vision can occur quasi-independently of the other, and is separately handled by a quite different processing system. In the 11 years since publication, the book has provoked (...) considerable interest and debate - throughout both cognitive neuroscience and philosophy, while the field has continued to flourish and develop. -/- For this new edition, the text from the original edition has been left untouched, standing as a coherent statement of the authors' position. However, a very substantial epilogue has been added to the book in which Milner and Goodale review some of the key developments that support or challenge the views that were put forward in the first edition. The new chapter summarizes developments in various relevant areas of psychology, neuroscience and behaviour. It notably supplements the main text by updating the reader on the contributions that have emerged from the use of functional neuroimaging, which was in its infancy when the first edition was written. Neuroimaging, and functional MRI in particular, has revolutionized the field over the past 11 years by allowing investigators to plot in detail the patterns of activity within the visual brains of behaving and perceiving humans. The authors show how its use now allows scientists to test and confirm their proposals, based as they then were largely on evidence accrued from primate neuroscience in conjunction with studies of neurological patients. (shrink)