IS THE mind locked into the brain? Are conscious experiences just bits of the brain? That鈥檚 the way it looks to most people, including a large number of researchers. So it might come as a bit of a shock to discover that quite a few scientists and philosophers disagree.
According to the standard model of the mind sciences, the brain encodes information about the world, the body and its own internal operations in 鈥渘eural representations鈥�, or stored information. This is used in memory, thinking, problem-solving, planning, physical actions and so on. The model insists that the 鈥渕ind鈥� is simply the functioning of the brain, thought of as an information processing system. While the precise workings of this system may be debatable, the consensus for the past 50 years or so is that mind must be 鈥渋n鈥� the brain. The same goes for conscious experiences: if these are produced by the mind in the brain, they must be in the brain too. The shorthand for this is 鈥減henomenological internalism鈥�.
Dissent, however, is obvious in a number of recently published books, as evidence emerges that the mind鈥檚 operations are not always confined to the brain, and that not all experiences seem to be in the brain either. It is obvious, for example, that living brains are not isolated systems. As W. Teed Rockwell points out in Neither Brain nor Ghost, the mind鈥檚 operations are not merely the function of a network of interacting cranial neurons, but depend on the complex interactions between brain, nervous system, body and world, which together form a dynamic system whose operations cannot completely be broken down into their constituents.
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In his forthcoming book Mind in Life, Evan Thompson extends this view, arguing that mental life is also the life of the body in the world, and that the self-organising features of mind are enriched versions of the self-organising features of life. For similar reasons, in Action in Perception, Alva No毛 rejects the idea that perception is a process in the brain with the perceptual system acting as a 鈥渃amera鈥� which constructs an internal representation, or 鈥減hotograph鈥�, of the world that can be separated from subsequent thought and action. Instead, he argues that perception is a skilful bodily activity which involves the whole animal interacting with its environment.
The existence of such mind-body-world interactions are supported by fascinating research. In a famous study on 鈥渋nattentional blindness鈥� in 1999, Daniel Simons and Christopher Chabris asked people to watch a video clip and count the times one of two teams of basketball players took possession of the ball. Many people (around 40 per cent) didn鈥檛 notice a man in a gorilla suit entering stage right, doing a jig in the centre of the screen and then leaving, stage left. The clip demonstrated how we don鈥檛 see what we don鈥檛 pay attention to, even when it is in front of our eyes.
Equally surprising were studies of 鈥渃hange blindness鈥� such as those done by Simons and Dan Levin in 1998. They got investigators to ask pedestrians for directions. While in conversation, two men rudely carried a door between the groups, and the investigator swapped places with the man carrying the back of the door. Only around half of those giving directions noticed the change. So we don鈥檛 notice major changes in what we are gazing at unless fast transitions capture our attention, or we happen to focus our attention on the precise features that change.
鈥淭he 鈥榮tandard model鈥� of perception has got to be wrong鈥�
The bottom line is that the 鈥渟tandard model鈥� of perception, that we build up a detailed and complete inner representation of the external world through successive eye movements from the incomplete information arriving at our retinas, must be wrong. If such a complete representation was updated moment-by-moment, we would notice changes in the visual field by comparing our current view with the complete records we already have. We often don鈥檛.
The alternative notion suggests that we perceive perhaps five or six features at any moment, but are free to pick up any other features as we need them. The reason we think the visual world is so rich in detail is because the world does have this detail and we see this wherever we look. We do not need to build up a complete, detailed inner representation of the world around us because the world itself stores all the relevant information and we can pick up whatever we need. So seeing is a bit like exploring objects by touch.
Some defenders of this 鈥渆nactive鈥� approach claim that if we understand perceptual functioning as mastering a set of sensory-motor skills, we can also understand the nature of conscious experience 鈥� including qualities such as colour and feel 鈥� in this way. This might help to bridge the explanatory gap between the physical world and consciousness.
The idea that there may be a motor component in, say, visual perception, is not new to psychology. Take Ivo Kohler鈥檚 famous experiments with distorting spectacles in the early 1960s. He put his volunteers in prism goggles: when they turned their heads right, objects appeared broader, and vice versa, producing a 鈥渃oncertina effect鈥� overall. If they moved their heads up and down, objects seemed to slant one way and then the other, giving a 鈥渞ocking-chair鈥� effect.
After several weeks exploring the world in a sensory-motor way with the goggles, the perceptual system adapts to the new 鈥渞ealities鈥� and this world appears relatively normal. Amazingly, if the subject removes the goggles after weeks or months, the distortions appear in reverse, an effect that can persist for days. So the 鈥減henomenal world鈥� 鈥� the world we think of as the everyday 鈥減hysical world鈥� 鈥� is at least in part a construct of mind, brain and body interacting with the environment.
Crucially, this experienced world appears to be outside the brain, which supports a form of phenomenological externalism (the opposite of phenomenological internalism). This is a serious theoretical challenge. Unlike physical things, we do not normally think of conscious experiences as having 鈥渓ocation鈥� (where they happen) or 鈥渆xtension鈥� (spacial dimensions). Recent books such as Antti Revonsuo鈥檚 Inner Presence argue persuasively that nearly all the qualities of experience do have a phenomenal location and extension, as they form part of the spatially extended phenomenal world.
Enactive theorists stress the spatially extended nature of experience for a different reason: they link such experiences to the extended relationship between brains, bodies and worlds. Revonsuo, however, begs to differ. As he points out, such 3D phenomenal worlds are also constructed in dreams, which do not require such active sensory-motor interactions. For him, dreams and the worlds we experience when awake are virtual realities that literally exist inside brains.
What are we to make of all this? Putting in a small plug for our upcoming Blackwell Companion to Consciousness, chapters by Francis Crick and Kristof Koch, Geraint Rees and Chris Frith, Jaak Panksepp, Semir Zeki and many others present extensive evidence for the involvement of brain systems in constructing experiences. So, in that the enactive approaches try to minimise or even dismiss the importance of the brain and its neural representations in the operations of mind and consciousness, they are probably wrong. On the other hand, in so far as these approaches refocus attention on the way that mental processes are embedded, not just in the brain, but in an entire body in dynamic interaction with the world, they have an important message for science.
The realisation that most experiences seem to have both external location and extension also opens up a new way of understanding their relationship to what we normally think of as the 鈥減hysical world鈥�. Rather than being 鈥渁part from鈥� what we experience, this physical world we perceive is a very large 鈥減art of鈥� our experience.
