Man hunched over table, thinking

The science of consciousness

Consciousness is one of the last great mysteries of modern science

Zoom in on the brain, and you’ll see a dense network of cells. The vivid quality of our conscious experience – our emotions, imagination, dreams and mystical experiences – are all underpinned by a flurry of electrical activity, neurons firing and interacting in different sets of patterns. Every aspect of the mind, most neuroscientists now believe, can be explained in mechanistic terms.

Francis Crick was one of the first to propose that consciousness or awareness is underpinned by brain activity alone – what he called his ‘astonishing hypothesis’. In the 1960s he argued that neuroscientists must search for the neurons that fire specifically during conscious moments – the so-called neural correlates of consciousness.

Of course, many neurons are active when we are conscious, but that doesn’t mean they are necessarily contributing to a conscious experience. One way to narrow the search is to compare a sensory system operating with or without conscious awareness (eg by using backward masking; see ‘Unconscious vision’). An alternative is to examine the impact of different types and doses of anaesthetics, which can selectively remove aspects of conscious experience.

Although not certain, there is a growing consensus that consciousness is not located in one specific part of the brain but is distributed around the brain in a kind of network. Some liken it to a virtual ‘workspace’ that draws upon unconscious neural activity all around the brain, assimilating our conscious view of the world.

This view is a little like a security guard using security cameras to monitor what is going on around a building, which is curiously similar to an early metaphor for consciousness, in which a tiny man – the homunculus – sat in the brain absorbing information from the outside world and deciding what the body should do.

Lead image:

Creative Ignition/Flickr CC BY

About this resource

This resource was first published in ‘Thinking’ in September 2006 and reviewed and updated in August 2014.

Cell biology, Neuroscience, Psychology, History
Education levels:
16–19, Continuing professional development