Monday, August 13, 2012

Chris D. Frith - Consciousness Is for Sharing: A Commentary on Graziano and Kastner - Human consciousness and its relationship to social neuroscience: A novel hypothesis


Michael S. A. Graziano and Sabine Kastner, both of Princeton University, published an interesting paper last year, Human consciousness and its relationship to social neuroscience: A novel hypothesis. They propose an understanding of consciousness as a construct of social perception processes. Their model suggests that the specialized neuronal circuits (they use the term "machinery" a lot) that allow human beings to be socially intelligent are also responsible for constructing models of other people’s minds (theory of mind), which allows us to predict the behavior of others. 

Here is the part that really interests me:
In the present hypothesis, awareness is a perceptual reconstruction of attentional state; and the machinery that computes information about other people’s awareness is the same machinery that computes information about our own awareness.
I'm not sure I agree with this last sentence, but the idea of awareness being constructed from attention is essential to where my own thinking is headed.

Here is the full abstract:
A common modern view of consciousness is that it is an emergent property of the brain, perhaps caused by neuronal complexity, and perhaps with no adaptive value. Exactly what emerges, how it emerges, and from what specific neuronal process, are in debate. One possible explanation of consciousness, proposed here, is that it is a construct of the social perceptual machinery. Humans have specialized neuronal machinery that allows them to be socially intelligent. The primary role of this machinery is to construct models of other people’s minds thereby gaining some ability to predict the behavior of other individuals. In the present hypothesis, awareness is a perceptual reconstruction of attentional state; and the machinery that computes information about other people’s awareness is the same machinery that computes information about our own awareness. The present paper brings together a variety of lines of evidence, including experiments on the neural basis of social perception, on hemispatial neglect, on the out-of-body experience, on mirror neurons, and on the mechanisms of decision-making, to explore the possibility that awareness is a construct of the social machinery in the brain.
The PDF linked to above contains the full paper and a series of commentaries, followed at the end by a response from the paper's authors to the commentaries. One of the commentaries that I quite liked came from Chris Frith, which is included below. Other commentaries include Christof Koch, Marco Iacoboni, Peter Carruthers and Vincent Picciuto, and David A. Leopold.

Full Citation:
Graziano, M.S.A., and Kastner, S. (2011). Human consciousness and its relationship to social
neuroscience: A novel hypothesis. Cognitive Neuroscience, 2 (2), 98–133 (Includes Discussion Paper, Commentaries, and Reply). DOI: 10.1080/17588928.2011.585230

Commentary Citation:
Frith, C.D. (2011): Consciousness is for sharing. Cognitive Neuroscience, 2:2, 117-118. DOI: 10.1080/17588928.2011.585230

Consciousness is for sharing

Chris D. Frith: Wellcome Trust Centre for Neuroimaging at University College London, UK, & Center of Functionally Integrative Neuroscience at Aarhus, University, Denmark
E-mail: c.frith@ucl.ac.uk
Abstract: I welcome the idea that consciousness, rather than being private, has a crucial role in understanding other minds. However, I believe that the critical mechanism underlying consciousness is metacognition; the ability to reflect upon and report mental states, whether our own or those of others. This allows us to share experiences and create a more accurate picture of the world.

Graziano & Kastner put forward an ingenious proposal about the origin of consciousness. This will be counter-intuitive for some, since, rather than being a private place for the self, consciousness emerges from the neural mechanism that permits tracking the attentional focus of others. The same mechanism is also used to represent our own attention. G & K suggest that consciousness emerges from this ability to represent our own attention. In this scheme consciousness is the meta-cognitive representation of our own awareness.
 
I must immediately declare a strong bias in favor of these ideas. Like G & K I believe that, if we want to understand consciousness we need to ask what it is for and, like them, my answer is that its fundamental function is social (Frith, 2008). I also like very much their novel and innovative idea that the machinery for representing of the focus of attention is applied to others as well as to ourselves. A major clue to where others are focussing their attention comes from eye gaze direction and humans are very accurate at judging where people are looking. The human iris, uniquely among primates (Kobayashi& Kohshima, 1997), is surrounded by white sclera making it easier to discern eye gaze direction. Thus, the evolution of this aspect of the human eye was not directly for the benefit of the individual, but for the benefit of others. This is confirmatory evidence for G & K’s suggestions about the social function of representations of the focus of attention.

However, I am unconvinced about the link with consciousness. People compute the direction of attention of others, where they are looking and what they see, automatically (Bayliss & Tipper, 2006; Qureshi, Apperly, & Samson, 2010). I conclude that we can take account of the attention of others without awareness. Also I don’t see why G & K’s account necessitates a subjective component. What does the feeling of being aware add to our ability to compute what people are attending to? The problem is to explain the function of this subjective component.

I believe we have all been misled by the longstanding idea that consciousness is private. On the contrary, conscious experience is the one outcome of our brain’s information processing that can be shared with others. It is this sharing that provides the value of consciousness. By sharing their experiences, two people can gain a more accurate perception than the best person working on her own (Bahrami et al., 2010). 

On this account the key component of consciousness is meta-cognition. I agree with G & K that a representation of our awareness, creating a feeling of being aware, is fundamentally important. But this meta-cognitive process can be applied to many things in addition to attention, including, for example, the feeling of agency. What we need to uncover is the neural mechanisms underlying meta-cognition. There is currently increasing interest in meta-cognition with developments in its empirical study (Lau, 2008) and quantification (Galvin, Podd, Drga, & Whitmore, 2003). Although, as yet, we know little of relevant neural mechanisms, the prefrontal cortex is strongly implicated (Del Cul, Dehaene, Reyes, Bravo, & Slachevsky, 2009; Fleming, Weil, Nagy, Dolan, & Rees, 2010).

But this critique of G &K concerns just minor details. I am very pleased to join them in promoting the idea that consciousness is not a private place. It has a major role in enabling the richness of human of social interactions.
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