You’d think that as neuroscience advances, we would be gaining a better understanding of ourselves, of who we fundamentally are. I’m afraid that’s not true, or at least not true yet. The problem seems to be, in part, because we do all have a very clear sense of who we are. As the philosopher Thomas Nagel writes, ‘There seems to be something it is like to be a human.’ This sense of consciousness has puzzled people for a long time,  and philosophers have examined this in many ways. I think it’s important to acknowledge, though, that it’s not just scientists or philosophers who are troubled by this. In fact, if you want to understand the nature of subjective experience, you could probably do a lot worse than to study the novel. In the 20th century, the literary form of the novel is probably the most systematic and detailed exploration of what it is to be a self, what self-awareness is, and again, sadly, has probably got much more data that would be useful for a Martian trying to understand the nature of human experience than anything that neuroscience has produced. 

The philosopher David Chalmers has suggested that there is a hard problem of consciousness. He suggests that this feeling of experience will never be understood by neuroscience. In response to this, although I believe he’s changed his view since, the neuroscientist Christof Koch said, ‘My job as a neuroscientist is to find the neural correlates of consciousness. When I’ve succeeded in doing that, you as a philosopher will be amongst the first to discover the error in the argument which said that my task was impossible.’ As neuroscientists, we should not be defeated. We should be trying to study what’s going on inside our heads that correlates with the experiences that we have, because that is a great challenge. My own feeling is, however, that we should probably be focussing on memory, on visual perception and on sleep before we tackle the ultimate problem of consciousness. If I were in charge of large amounts of neuroscience funding, I’m not sure I would be driven solely by the narcissistic preoccupation of what it is like to be me.

Neuroscience as a discipline did not entirely exist before the 1990s. If you’re dealing with an anaesthetised, paralysed animal, there’s not much going on in the head in terms of thinking and experience, so scientists studying the brain outside of its context of the environment and of society made great progress. In parallel to this, there were psychologists who manifested their interest in behaviour but not in the study of the brain’s function.

This lack of interest in the self changed in the 1990s, when neuroscience took upon itself the challenge of understanding everything about the human condition: humour, love, memory, etc. In fact, what it mostly did was to recapitulate the late 19th and early 20th century history of psychology, but just did it inside the scanner. In other words, it was like making the same discoveries but with pictures. In many cases, no further insights were given.

True progress will come from a proper interdisciplinary collaboration between people who look at the brain from different perspectives. That will include psychologists, because without paradigms of behaviour and ways of understanding what you’ve discovered in your experiments, you’re never going to proceed.

We’re also going to need the people who’ve been studying the human condition and human experience for millennia – dancers and choreographers, for example, to understand human movement; novelists, to understand the nature of subjective experience; magicians, to understand misdirection; and painters, to help us explore visual perception. This exploration needs to take place in spaces of mutual respect. We have to build collaborations where the terminology from each domain is equally understood and exchanged, where we can publish our findings in our own professional journals, but that we build spaces where people who see the world differently, perhaps in non-overlapping discourses, can effectively collaborate. That’s where the future of brain science lies in examining human experience in all its forms, with experts from many different disciplines.

Given the huge investments in brain research, it would be reasonable to expect that there are dividends that are paying in terms of everyday life. But I’m afraid, from my perspective, the story here is somewhat disappointing. In education, if you take neurotypical cases – that’s to say people without a particular brain pathology or learning disability – there’s very little, if anything, that contemporary neuroscience can or should tell us about how to educate our children. In fact, there’s precious little from neuroscience that has any real world effect for thoughtful neuroscientists. That may partly be because we need to integrate our research better with societal priorities.

What’s clear, though, is that there is an enormous appetite for neuroscience. There are constantly people asking for the neuroscience of a leadership style or what neuroscience can tell us about economics or indeed what neuroscience can describe about how we get out of the pandemic lockdown. Most of this desire derives from a sense of wanting to understand what’s going on inside our heads, which neuroscience cannot satisfy. At the moment, there’s no brain scan that can tell you whether you’re suited to a particular job or not. In fact, if you want to understand what’s going on inside people’s heads, you’re better off studying their eye movements; in other words, where they’re looking in a scene. That gives you much more insight into what they’re doing than looking at the brain waves. In certain laboratory experiments we can just about tell whether somebody is looking at one picture or another picture if we image repeatedly. The notion of being able to read out somebody’s brain or determine some economic or educational priority on the basis of the neuroscientific finding is still far from practical.

Woody Allen famously said, ‘The brain is my second favorite organ.’ It’s natural to wonder whether brains are differentiated in the way that sex organs are without getting into thorny questions of gender identity. The answer on that is both interesting and perhaps mildly disappointing. It is the case that for almost any measure that you make of the brain, if you took a group of males and a group of females, there would be a difference on average between the two groups. The variability within each group in almost all dimensions is much greater than the variability between the groups. So, sadly, for those of us who would love to classify the world on the basis of gender, neurobiology does not support a simple story about the difference between the male and the female brain.

We’re consuming more and more and our desire to do so, very clearly, is driven by our brains. It’s natural to ask whether we can understand our desire to consume more by understanding the brain. On a paranoid level, it’s also interesting to ask whether those who are trying to sell or advertise things to us can understand how better to make us consume their own products through an understanding of the brain. It’s worth noting in passing that if you run the numbers on happiness and wealth, the curve asymptotes fairly rapidly, which is to say that below a certain level of income, a bit more money makes you a bit happier. A lot more money makes you a lot happier, but very rapidly you reach a level of income where more money doesn’t change your happiness.

But how can we sell to people better by understanding what’s going on inside their heads? One rather distressing experiment that has been done is the pleasure lever in rats. There is a reward system in the brains of mammals, which involves a chemical called dopamine. If you get a reward from having achieved a task or having got the thing that you want, you get a reward. Scientists found a way of directly stimulating the reward centre in rats using an electrode which they’d implanted, and then they cunningly connected that electrode to a lever. This is the ultimate hijacking of the brain: you can directly make people feel better, reward them using an electrical stimulus and that can be controlled by a lever. The rats who were in a cage that had that lever died of thirst because the reward that they could get from pressing the pleasure lever was more intense than from drinking. Short-circuiting the brain tapping directly into pleasure, therefore, is not a promising angle for enhancing human happiness.

If I were trying to sell you something, I would be more interested in measuring your eye movements. I’d be more interested in studying aspects of your physiology to measure your general arousal level by what’s called galvanic skin response – how sweaty you are. That correlates very well with pupil dilation, heart rate, breathing rate and so on. You could record gustatory secretions, which is to say the secretions in your stomach. When you see something that you’re interested in eating, your stomach secretes different juices. You could also measure sexual arousal through erection or through vaginal secretions, which would give you a very interesting insight into what turns people on. If you look at the pattern of flushing or of micro-gestures in the face, this gives you great insight into people’s emotional responses to what they’re seeing. 

However, the simplest things, such as eye movements, are very effective. If I can tell where you’re looking, I can tell what you’re interested in, whether you know it or not. Rather depressingly, we’re quite close to that. Our phones have a camera that points at ourselves to see where we’re looking, and it’s got a camera that points outside which tells it what we’re looking at. From that, it’s simple trigonometry. It can tell whether I’m interested in your shirt, because it can see that I’m looking down a little from your face at the shirt buttons, perhaps even trying to steal a glance at the logo. If you were in the shirt business, you’d be using this eye movement data to tell you who to advertise your shirts to. I think that the tracking of our movements, the surveillance of that is probably the next frontier in gaining insights into what’s going on inside our heads. And that’s where I’d put my money before I try to build mobile brain scanners to mine the neurobiological depths of potential consumers.

People have appealed to neuroscience to support any number of different conceptions of humanity and of differences between people. I suppose the good news here is that, as with physiology, genetics and anatomy, serious attempts to use neuroscience to back up racist theories – theories of the fundamental differences between genders or the incapacity of one group to perform as fully human to be accorded the same rights – have failed just in the way that genetics fails to back up racist theories. I’m happy that neuroscience, as a mature scientific discipline, cannot honestly be co-opted towards theories of racial superiority. That, for me, is the hallmark of a genuine scientific process.