Perception and report

consciousnessThe measurement problem in consciousness research

Rafael Malach, Weizmann Institute

Behavioural and Brain Sciences (2007) doi: 0.1017/S0140525X0700297X

Keywords: perception, reportability, neuron, consciousness, self
Malach argues that studies of brain processing can differentiate conscious perception from the process of reporting the perceptions, and that conscious perception does not require some higher-order read-out system or some form of self, but can be handled by groups of neurons, within which individual neurons provide the perceptual read-out or subjective experience.

Modern experimentation suggests that reporting can in fact be disentangled from perception, and that reportability is not essential to perception. On a more everyday level, Malach suggests that when subjects are sufficiently absorbed by their sensory perceptions, they ‘lose themselves’ in the sense of not having any introspection about what they are perceiving. A typical example is an interesting film in which the viewer is absorbed by the drama and suspends any personal introspection or attempts to report what they are experiencing.

One study (Hasson et al, 2004) did scan brain activation in subjects viewing a film. In general, the rear part of the brain, which is orientated towards the external environment, demonstrated widespread activation. In contrast, the front of the brain and some areas of the rear brain showed little activation. These less active areas are referred to as the ‘intrinsic system’ that deals with introspection, and the ‘first person’ or ‘self’ aspects of the mind. Reportability is presumed to arise in this part of the brain. This network shows a major reduction in activation at the times that perception is most absorbing. This observation is exactly the reverse of any notion that perception and reporting should work in tandem.

Malach speculates that these experimental findings support the idea that subjective experience arises in the areas where sensory processing occurs, rather than having to be referred on to any type of higher-order read out or some form of separate ‘self’. In this view, sensory perceptions are seen as arising in a group of neurons. Studies show that high neuronal firing rates over an extended duration and dense local connectivity of neurons is associated with consciousness.

Malach argues that this supports the view that consciousness arises in each of a number of single neurons in a network, rather than having to refer to some higher structure. The perception arises when all the neurons in a particular network are informed about the state of the others in the network. Thus the perception is suggested to be both assembled by, and read-out or subjectively experienced by the same set of neurons. Each active neuron is suggested to be involved in both creating and experiencing the perception.

This view of conscious perception has some important implications for consciousness theory as a whole. In the first place, it makes it possible to consider looking for the process by which consciousness arises in individual neurons rather than brain wide assemblies. This is more easily consistent with the recent findings that quantum coherence and possibly entanglement is functional in individual living cells. A further point is that the idea of consciousness in neurons or small high density areas undermines the attempt by some consciousness theorists to try and conflate consciousness and self-consciousness, and then claim that a deconstruction of the self has explained consciousness.

 

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