The amoral molecule


The cuddle drug, the trust hormone, the moral molecule: oxytocin (OXT), has been called all these things and more.  You can buy nasal sprays of the stuff online in the promise that some judicious squirting will make people trust you more. In a recent book neuroscientist-cum-economist Paul Zak goes the whole hog, saying that if we only let ourselves be guided by this “moral molecule”, prosperity and social harmony will certainly ensue.

Behind this outlandish and rather ridiculous claim lies some fascinating science. The story starts with the discovery that injecting female virgin rats with OXT triggers maternal instincts, and that these same instincts in mother rats are suppressed when OXT is blocked.  Then came the finding of different levels of OXT receptors in two closely related species of vole. The male prairie vole, having high levels, is monogamous and helps look after its little vole-lets.  Male meadow voles, with many fewer receptors, are aggressive loners who move from one female to the next without regard for their offspring. What’s more, genetically manipulating meadow voles to express OXT receptors turns them into monogamous prairie-vole-a-likes. These early rodent studies showed that OXT plays an important and previously unsuspected role in social behaviour.

Studies of oxytocin and social cognition really took off about ten years ago when Paul Zak, Ernst Fehr, and colleagues began manipulating OXT levels in human volunteers while they played a variety of economic and ‘moral’ games in the laboratory.  These studies showed that OXT, usually administered by a few intranasal puffs, could make people more trusting, generous, cooperative, and empathetic.

For example, in the so-called ‘ultimatum game’ one player (the proposer) is given £10 and offers a proportion of it to a second player (the responder) who has to decide whether or not to accept. If the responder accepts, both players get their share; if not, neither gets anything.  Since these are one-off encounters, rational analysis says that the responder should accept any non zero proposal, since something is better than nothing.  In practice what happens is that offers below about £3 are often rejected, presumably because the desire to punish ‘unfair’ offers outweighs the allure of a small reward. Strikingly, a few whiffs of OXT makes donor players more generous, by almost 50% in some cases. And the same thing happens in other similar situations, like the ‘trust game’: OXT seems to make people more cooperative and pro-social.

Even more exciting are recent findings that OXT can help reduce negative experiences and promote social interactions in conditions like autism and schizophrenia.  In part this could be due to OXTs general ability to reduce anxiety, but there’s likely more to the story than this.  It could also be that OXT enhances the ability to ‘read’ emotional expressions, perhaps by increasing their salience.  Although clinical trials have so far been inconclusive there is at least some hope for new OXT-based pharmacological treatments (though not cures) for these sometimes devastating conditions.

These discoveries are eye-opening and apparently very hopeful. What’s not to like?


The main thing not to like is the idea that there could be such a simple relationship between socially-conditioned phenomena like trust and morality, and the machinations of single molecule.  The evolutionary biologist Leslie Orgel said it well with his ‘third rule’: “Biology is more complicated than you imagine, even when you take Orgel’s third rule into account”.  Sure enough, the emerging scientific story says things are far from simple.

Carsten de Dreu of the University of Amsterdam has published a series of important studies showing that whether oxytocin has a prosocial effect, or an antisocial effect, seems to depend critically on who the interactions are between. In one study, OXT was found to increase generosity within a participant’s ingroup (i.e., among participants judged as similar) but to actually decrease it for interactions with outgroup members.  Another study produced even more dramatic results: here, OXT infusion led volunteers to adopt more derogatory attitudes to outgroup members, even when ingroup and outgroup compositions were determined arbitrarily. OXT can even increase social conformity, as shown in a recent study in which volunteers were divided into two groups and had to judge the attractiveness of arbitrary shapes.

All this should make us look very suspiciously on claims that OXT is any kind of ‘moral molecule’ as some might suggest.  So where do we go from here? A crucial next step is to try to understand how the complex interplay between OXT and behaviour is mediated by the brain. Work in this area has already begun: the research on autism, for example, has shown that OXT infusion leads to autistic brains better differentiating between emotional and non-emotional stimuli.  This work complements emerging social neuroscience studies showing how social stereotypes can affect even very basic perceptual processes. In one example, current studies in our lab are indicating that outgroup faces (e.g., Moroccans for Caucasian Dutch subjects) are literally harder to see than ingroup faces.

Neuroscience has come in for a lot of recent criticism for reductionist ‘explanations’ in which complex cognitive phenomena are identified with activity in this-or-that brain region.  Following this pattern, talk of ‘moral molecules’ is, like crime in multi-storey car-parks, wrong on so many levels. There are no moral molecules, only moral people (and maybe moral societies).  But let’s not allow this kind of over-reaching to blind us to the progress being made when sufficient attention is paid to the complex hierarchical interactions linking molecules to minds.  Neuroscience is wonderfully exciting and has enormous potential for human betterment.  It’s just not the whole story.

This piece is based on a talk given at Brighton’s Catalyst Club as part of the 2014 Brighton Science Festival.


Accurate metacognition for visual sensory memory


I’m co-author on a new paper in Psychological Science – a collaboration between the Sackler Centre (me and Adam Barrett) and the University of Amsterdam (where I am a Visiting Professor).  The new study addresses the continuing debate about whether the apparent rich content of our visual sensory scenes is somehow an illusion, as suggested by experiments like change blindness.  Here, we provide evidence in the opposite direction by showing that metacognition (literally, cognition about cognition) is equivalent for different kinds of visual memory, including visual ‘sensory’ memory which reflects brief, unattended, stimuli.  The results indicate that our subjective impression of seeing more than we can attend to is not an illusion, but is an accurate reflection of the richness of visual perception.

Accurate Metacognition for Visual Sensory Memory Representations.

The capacity to attend to multiple objects in the visual field is limited. However, introspectively, people feel that they see the whole visual world at once. Some scholars suggest that this introspective feeling is based on short-lived sensory memory representations, whereas others argue that the feeling of seeing more than can be attended to is illusory. Here, we investigated this phenomenon by combining objective memory performance with subjective confidence ratings during a change-detection task. This allowed us to compute a measure of metacognition-the degree of knowledge that subjects have about the correctness of their decisions-for different stages of memory. We show that subjects store more objects in sensory memory than they can attend to but, at the same time, have similar metacognition for sensory memory and working memory representations. This suggests that these subjective impressions are not an illusion but accurate reflections of the richness of visual perception.

The 30 Second Brain


This week I’d like to highlight my new book, 30 Second Brain,  published by Icon Books on March 6th.  It is widely available in both the UK and the USA.  To whet your appetite here is a slightly amended version of the Introduction.

[New Scientist have just reviewed the book]

Understanding how the brain works is one of our greatest scientific quests.  The challenge is quite different from other frontiers in science.  Unlike the bizarre world of the very small in which quantum-mechanical particles can exist and not-exist at the same time, or the mind-boggling expanses of time and space conjured up in astronomy, the human brain is in one sense an everyday object: it is about the size and shape of a cauliflower, weighs about 1.5 kilograms, and has a texture like tofu.  It is the complexity of the brain that makes it so remarkable and difficult to fathom.  There are so many connections in the average adult human brain, that if you counted one each second, it would take you over 3 million years to finish.

Faced with such a daunting prospect it might seem as well to give up and do some gardening instead.  But the brain cannot be ignored.  As we live longer, more and more of us are suffering  – or will suffer – from neurodegenerative conditions like Alzheimer’s disease and dementia, and the incidence of psychiatric illnesses like depression and schizophrenia is also on the rise. Better treatments for these conditions depend on a better understanding of the brain’s intricate networks.

More fundamentally, the brain draws us in because the brain defines who we are.  It is much more than just a machine to think with. Hippocrates, the father of western medicine, recognized this long ago:  “Men ought to know that from nothing else but the brain come joys, delights, laughter and jests, and sorrows, griefs, despondency, and lamentations.” Much more recently Francis Crick – one of the major biologists of our time  – echoed the same idea: “You, your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behaviour of a vast assembly of nerve cells and their associated molecules”.  And, perhaps less controversially but just as important, the brain is also responsible for the way we perceive the world and how we behave within it. So to understand the operation of the brain is to understand our own selves and our place in society and in nature, and by doing so to follow in the hallowed footsteps of giants like Copernicus and Darwin.

But how to begin?  From humble beginnings, neuroscience is now a vast enterprise involving scientists from many different disciplines and almost every country in the world.  The annual meeting of the ‘Society for Neuroscience’ attracts more than twenty thousand (and sometime more than thirty thousand!) brain scientists each year, all intent on talking about their own specific discoveries and finding out what’s new.  No single person – however capacious their brain – could possible keep track of such an enormous and fast-moving field.  Fortunately, as in any area of science, underlying all this complexity are some key ideas to help us get by.  Here’s where this book can help.

Within the pages of this book, leading neuroscientists will take you on a tour of fifty of the most exciting ideas in modern brain science, using simple plain English.  To start with, in ‘Building the brain’ we will learn about the basic components and design of the brain, and trace its history from birth (and before!), and over evolution.  ‘Brainy theories’ will introduce some of the most promising ideas about how the brain’s many billions of nerve cells (neurons) might work together.  The next chapter will show how new technologies are providing astonishing advances in our ability to map the brain and decipher its activity in time and space.  Then in ‘Consciousness’ we tackle the big question raised by Hippocrates and Crick, namely the still-mysterious relation between the brain and conscious experience – how does the buzzing of neurons transform into the subjective experience of being you, here, now, reading these words? Although the brain basis of consciousness happens to be my own particular research interest, much of the brain’s work is done below its radar – think of the delicate orchestration of muscles involved in picking up a cup, or in walking across the room.  So in the next chapter we will explore how the brain enables perception, action, cognition, and emotion, both with and without consciousness.  Finally, nothing – of course – ever stays the same. In the last chapter – ‘the changing brain –we will explore some very recent ideas about how the brain changes its structure and function throughout life, in both health and in disease.

Each of the 50 ideas is condensed into a concise, accessible and engaging ’30 second neuroscience’.  To get the main message across there is also a ‘3 second brainwave’, and a ‘3 minute brainstorm’ provides some extra food for thought on each topic. There are helpful glossaries summarizing the most important terms used in each chapter, as well as biographies of key scientists who helped make neuroscience what it is today.  Above all, I hope to convey that the science of the brain is just getting into its stride. These are exciting times and it’s time to put the old grey matter through its paces.

Update 29.04.14.  Foreign editions now arriving!


All watched over by search engines of loving grace


Google’s shopping spree has continued with the purchase of the British artificial intelligence (AI) start-up DeepMind, acquired for an eye-watering £400M ($650M).  This is Google’s 8th biggest acquisition in its history, and the latest in a string of purchases in AI and robotics. Boston Dynamics, an American company famous for building agile robots capable of scaling walls and running over rough terrain (see BigDog here), was mopped up in 2013. And there is no sign that Google is finished yet. Should we be excited or should we be afraid?

Probably both. AI and robotics have long promised brave new worlds of helpful robots (think Wall-E) and omniscient artificial intelligences (think HAL), which remain conspicuously absent. Undoubtedly, the combined resources of Google’s in-house skills and its new acquisitions will drive progress in both these areas. Experts have accordingly fretted about military robotics and speculated how DeepMind might help us make better lasagne. But perhaps something bigger is going on, something with roots extending back to the middle of the last century and the now forgotten discipline of cybernetics.

The founders of cybernetics included some of the leading lights of the age, including John Von Neumann (designer of the digital computer), Alan Turing, the British roboticist Grey Walter and even people like the psychiatrist R.D. Laing and the anthropologist Margaret Mead.  They were led by the brilliant and eccentric figures of Norbert Wiener and Warren McCulloch in the USA, and Ross Ashby in the UK. The fundamental idea of cybernetics was consider biological systems as machines. The aim was not to build artificial intelligence per se, but rather to understand how machines could appear to have goals and act with purpose, and how complex systems could be controlled by feedback. Although the brain was the primary focus, cybernetic ideas were applied much more broadly – to economics, ecology, even management science.  Yet cybernetics faded from view as the digital computer took centre stage, and has remained hidden in the shadows ever since.  Well, almost hidden.

One of the most important innovations of 1940s cybernetics was the neural network, the idea that logical operations could be implemented in networks of brain-cell-like elements wired up in particular ways. Neural networks lay dormant, like the rest of cybernetics, until being rediscovered in the 1980s as the basis of powerful new ‘machine learning’ algorithms capable of extracting meaningful patterns from large quantities of data. DeepMind’s technologies are based on just these principles, and indeed some of their algorithms originate in the pioneering neural network research of Geoffrey Hinton (another Brit), who’s company DNN Research was also recently bought by Google and who is now a Google Distinguished Researcher.

What sets Hinton and DeepMind apart is that their algorithms reflect an increasingly prominent theory about brain function. (DeepMind’s founder, the ex-chess-prodigy and computer games maestro Demis Hassabis, set up his company shortly after taking a Ph.D. in cognitive neuroscience.) This theory, which came from cybernetics, says that the brains’ neural networks achieve perception, learning, and behaviour through repeated application of a single principle: predictive control.  Put simply, the brain learns about the statistics of its sensory inputs, and about how these statistics change in response to its own actions. In this way, the brain can build a model of its world (which includes its own body) and figure out how to control its environment in order to achieve specific goals. What’s more, exactly the same principle can be used to develop robust and agile robotics, as seen in BigDog and its friends

Put all this together and so resurface the cybernetic ideals of exploiting deep similarities between biological entities and machines.  These similarities go far beyond superficial (and faulty) assertions that brains are computers, but rather recognize that prediction and control lie at the very heart of both effective technologies and successful biological systems.  This means that Google’s activity in AI and robotics should not be considered separately, but instead as part of larger view of how technology and nature interact: Google’s deep mind has deep roots.

What might this mean for you and me? Many of the original cyberneticians held out a utopian prospect of a new harmony between people and computers, well captured by Richard Brautigan’s 1967 poem – All Watched Over By Machines of Loving Grace – and recently re-examined in Adam Curtis’ powerful though breathless documentary of the same name.  As Curtis argued, these original cybernetic dreams were dashed against the complex realities of the real world. Will things be different now that Google is in charge?  One thing that is certain is that simple idea of a ‘search engine’ will seem increasingly antiquated.  As the data deluge of our modern world accelerates, the concept of ‘search’ will become inseparable from ideas of prediction and control.  This really is both scary and exciting.