Vol 14 (2008)

Editorial

Psyche, attention and consciousness  Full Text
Gabriel Kreiman, Naotsugu Tsuchiya  

 

Symposia

Attentional Networks and the Semantics of Consciousness Summary Full Text
Michael Posner
The term consciousness is an important one in the vernacular of the western literature in many fields. It is no wonder that scientists have assumed that consciousness will be found as a component of the human brain and that we will come to understand its neural basis. However, there is rather little in common between consciouness as the neurologist would use it to diagnose the vegetative state, how the feminist would use it to support raising male consciousness of the economic plight of women and as the philosopher would use it when defining the really hard question of the subjective state of awareness induced by sensory qualities. When faced with this kind of problem it is usual to subdivide the term into more manageable perhaps partly operational definitions. Three meanings that capture aspects of consciousness are: (1) the neurology of the state of mind allowing coherent orientation to time and place (2) the selection of sensory or memorial information for awareness and (3) the voluntary control over overt responses. In each of these cases the mechanisms of consciousness overlap with attentional networks that have been explored with the methods of cognitive neuroscience. In this paper we explore the overlap and discuss how to exploit the growing knowledge of attentional networks to constrain ideas of consciousness. 
Does Attention Accompany the Conscious Awareness of Both Location and Identity of an Object? Summary Full Text
Shahab Ghorashi, Lisa N Jefferies, Jun-ichiro Kawahara, Katsumi Watanabe
The question of whether consciousness and attention are the same or different phenomena has always been controversial. In trying to find an answer to this question, two different measures for consciousness and attention were used to provide the potential for dissociating between them. Conscious awareness of either the location or the identity of the object was measured as the percentage of correct reports of that aspect. The location of the focus of attention, on the other hand, was determined using the shooting-line illusion (SLI). In the SLI, a static line is perceived as growing from the location of a preceding cue (i.e., the location of the focus of attention). To investigate whether conscious awareness of the location of an object could be dissociated from conscious awareness of its identity, the attentional blink (AB) was used. It is known that during the AB, identification of the second of two consecutively and briefly presented targets (T1 and T2) is impaired if the temporal lag between the two targets is less than about 500 ms. In three experiments, an SLI was induced during the AB to determine whether attention was at the location of T2 when the observer was consciously aware of its location, its identity, or both. Observers were instructed to report the identity and location of the targets, and the direction of the SLI. Three important findings emerged. First, the SLI was seen as growing from T2 only when T2 was identified correctly. Second, observers could report T2 location even when unaware of its identity. Third, the SLI occurred from T2 only when T2 identity – not its location – could be reported correctly. These results indicate that focal attention does not necessarily accompany conscious awareness of some aspects of the object, while it does accompany conscious awareness of its identity. 
Varieties of attention and of consciousness: evidence from neuropsychology Summary Full Text
Paolo Bartolomeo
Do we need to attend to an object in order to be conscious of it, and are the objects of our attention necessarily part of our conscious experience? A tight link between attention and consciousness has often been assumed, but it has recently been questioned, on the basis of psychophysical evidence suggesting a double dissociation between top-down attention and consciousness. The present review proposes to consider these issues in the light of time-honored distinctions between exogenous and endogenous forms of attention and between primary and reflective forms of consciousness. These distinctions permit to interpret results from several sources of evidence, including patterns of performance of brain-damaged patients with visual neglect, as suggesting that exogenous attention is a necessary condition for primary visual consciousness to emerge. Visual neglect, which typically results from damage to fronto-parietal networks in the right hemisphere, entails an inability to orient to and to detect contralesional objects. Importantly, neglect patients are not only unable to verbally report contralesional objects, but may also act as if these objects did not exist, for example by bumping into them, thus suggesting an impairment of primary perceptual consciousness. Less frequently, neglect patients may instead show forms of “implicit” knowledge of neglected items, perhaps indicating a deficit of more reflective forms of consciousness, such as those subserving verbal reportability. The integration of several sources of evidence, such as phenomenology, experimental psychology and neuroscience, is needed to further explore the taxonomy of these processes and to identify their neural correlates. 
Attention and Working Memory: Tools for Understanding Consciousness Summary Full Text
Jill T Shelton, Emily M Elliott, Nelson Cowan

Most would agree that attention and consciousness are related to one another; however, this is not to say that everything being attended to is available to consciousness, or vice versa. In fact, some researchers argue that information being attended to is not always under the control of top-down attentional processes, and attention can often be directed towards input that remains outside of consciousness (Koch & Tsuchiya, 2006). For example, the attentional system could become oriented to a familiar smell entering the environment. Attending to this sensory input could even bring on sadness without awareness of the culprit behind this sudden onset of emotion. Further examination could be facilitated by selecting the input being received by the olfactory system, leading to the conscious realization that the floral aroma filling the room reminds one of a recently-attended funeral. The foregoing example raises several issues that speak to the connection between attention and consciousness. First, a person is not always consciously aware of what he or she is attending to, which suggests attention and consciousness are separate, albeit related, constructs. Attentional orienting is one example of how attention can be shifted in response to changing states in the environment, without the voluntary control of the organism (Cowan, 1995). Second, the contents of the unconscious mind can influence ongoing cognitive operations in a variety of ways that are not yet fully understood. Third, attention can be used to draw important information into conscious awareness, making the study of attentional processes useful as a tool to explore the nature of consciousness. The relationship between attention and consciousness, and the utility of this relationship for understanding these complex constructs, will be discussed, followed by a consideration of the remaining issues and the tools that may be used to address them. 

On the Relation between Attention and Consciousness Summary Full Text
John Taylor
There is presently an ongoing debate about the relation between attention and consciousness, fuelled by results from paradigms which probe the interaction between these two faculties, such as the attentional blink, object substitution masking and change blindness. Simulations of these paradigms were shown recently to be able to provide an explanation of them from a single overarching control model of attention. This model furthermore allows exploration of how consciousness might be created as a copy of the attention movement control signal, and indicates the complex possibilities inherent in attention. The paper develops this theme and presents a set of questions and their possible answers arising from the need for the existence of a set of inner selves associated with different attention copy signals in different modalities to provide a unified phenomenological experience. The paper concludes with a set of comments on the Hilbert questions of the Special Issue. 
Do consciousness and attention have shared neural correlates? Summary Full Text
Andrea Eugenio Cavanna, Andrea Nani
Over the last few years our understanding of the brain processes underlying consciousness and attention has considerably improved, mainly thanks to the advances in functional neuroimaging techniques. However, caution is needed for the correct interpretation of empirical findings, since both research and reflection are hampered by a number of conceptual difficulties. This paper reviews some of the most relevant theoretical issues surrounding the concepts of consciousness and attention in the neuroscientific literature, and presents the implications of these reflections for a coherent model of the neural correlates of these cognitive functions. Although orthogonally defined as essentially separate neural processes, consciousness and attention show a consistent and overlapping pattern of brain activity, specifically recurrent processing within fronto-parietal association areas. Future research will shed more light on the possible relationship of processes that relate to common brain activity across functions.