Human behaviour cannot be understood through brain scans.
If you step outside right now, you’ll find a lot of leaves have fallen on to the pavement. Some have blown away, but have left an imprint there, so you get these beautiful patterns left on the paving stones. If I were to show you a photograph of one of those prints, I think most people would say that they saw the print of a leaf. But that’s not what you would see; that would be your interpretation of what you see. What you would actually see is a patch of colour superimposed on another patch of colour.
You interpret what you see in this way because you have prior experiences of seeing leaves; you would have experienced the leaching of pigment from leaves that remains on the pavement, and you have experiences of things changing over time – that something that was there is no longer there. In fact, most human activity is the interpretation of data that we perceive through our senses rather than the mere representation of that data.
Such interpretations can be contested. Science tries to avoid that contestation by the repetition of experiments, having large numbers of results and looking at the significance of the numbers that are revealed.
One problem facing neuroscience is that it is plagued by very small signals generated from very small numbers of volunteers who are prepared to put their heads into a scanner, which are then enhanced through the amazing imagery capacity of information technology. But those images are still contested.
Another problem is that neuroscience is in many ways a fledgling science and plagued by numerous disagreements, even among its proponents. For example, some would argue that a brain on its own does not explain much; it needs to be understood in context – with its environment, with other brains. Other neuroscientists may not see it that way. This contestation of interpretation and meaning is crucial to understanding what neuroscience can and cannot tell us.
Others have also pointed out that some neuroscientists notoriously try to smuggle the language of consciousness into how they describe the processes going on in the brain. They will say things like neurons ‘signal’ or ‘provide information’ or ‘respond to’. But neurons can’t do those things; that’s what we as human beings do. Neurons simply generate and transmit electrical impulses.
Neuroscience is also plagued by vague language. So neuroscientists may talk about one phenomenon being ‘associated with’ or ‘influenced by’ another. These are descriptions, not explanations.
It’s also the case that we perceive many things simultaneously. In an experimental setting, we somehow have to prioritise the experiences the experimenter is asking us to focus on, yet there may be activity going on at the same time in our brains that we are not conscious of. For example, we are constantly maintaining a state of homeostasis, such as keeping our balance or an optimal body temperature, which may cloud other things that are going on.
I don’t say these things to dismiss neuroscience, but because it is important to say that it is a contested field with some important barriers.
Neuroscience also suffers from presenting a deficit model of the brain. There is a lot of focus on what happens when a part of the brain is damaged and what this supposedly reveals about what would normally be there. But suggesting that normality is the opposite of damaged is a bit like trying to study democracy through only looking at dictatorships because it is assumed that one is the opposite of the other. That’s not true – and that indicates that there are limits to some of the experiments that are currently being reported.
In other words, the study of the brain is incredibly complicated. If I wanted to study a butterfly colony, for example, I could say that all things are ultimately physical, that butterflies are made of protons, neutrons and electrons. Therefore, all I need to do to understand that colony is to sum up where all these particles are, how they interact and how they move across time. In reality, such an effort would simply be far too time-consuming; there’s not enough time in the universe to determine what would happen. Hence, I don’t use physics to understand butterfly colonies.
My thoughts and actions may be reflected in my brain but they are part of a social field of relations, not just a neural or chemical set of relations. For example, a slip of the tongue may leave a neural or chemical signature that can be measured, but it is a really uninteresting way of describing what happens. My degree of embarrassment will have nothing to do with that neural signature; it will have to do with social context. Likewise, I don’t think neuroscience is about to explain anything sophisticated or important like the existence of slavery or sex discrimination.
What is clear, however, is that the language of neuroscience has been hijacked by some people in order to further pre-existing political agendas. I largely work in the field of security and I could show you a whole series of US Department of Defense white papers in this vein, with titles like ‘The Neurobiology of Political Violence’, ‘Neuroscience Insights on Radicalisation’, and so on. The language of neuroscience has been hijacked and adapted to many other fields.
However, to suggest that neuroscience is corrupting or influencing society is to put things entirely the wrong way round. Science, while shaping society, is also a product of the particular society and cultural mood from within which it emerges. The current cultural mood could be categorised as one dominated by a fear of change, a sense of limits, and a feeling of fragility which encourages a particularly dystopian outlook. That dystopian outlook, whether they know it or not, guides many scientists as to what they go off and investigate. As a consequence, we have apocalyptic interpretations of environmental science and deterministic presumptions presented by neuroscience.
Karl Marx, in his introduction to A Contribution to the Critique of Hegel’s Philosophy of Right in 1844 (an article most famous for the idea that ‘religion is the opium of the people’), made two points that are very appropriate here. Firstly, he writes: ‘Theory becomes a material force as soon as it has gripped the masses.’ So here we have Marx, a materialist, who understands that matter is not all that matters, and that ideas can have a material impact.
Secondly, he writes: ‘The immediate task of philosophy, once the holy form of human self-estrangement has been unmasked, is to unmask self-estrangement in its unholy forms.’ That seems very pertinent to our current situation. Having been through a period when we have revealed the limits of religious determinism, now we need to reveal the limits of neurodeterminism.
This is an edited version of a speech given at the Battle of Ideas festival on Sunday 20 October 2013 at the Barbican Centre in London. You can watch video of the whole debate, ‘Soul on the slab: is there no limit to what neuroscience can do?’, at WORLDbytes.