From New Scientist, by Chris Frith, a neuroscientist at the Wellcome Trust Centre for Neuroimaging at University College London. His book Making Up the Mind: How the brain creates our mental world was published by Blackwell earlier this year.

Earlier this year I temporarily gave up any pretence of having free will for the duration of a transatlantic flight to a meeting in California to discuss free will and the brain. This endeavour is the kind of Big Question that the John Templeton Foundation funds when not, more controversially, encouraging interactions between science and religion.

My fellow delegates included the great and the good in everything from biophysics and neuroscience to philosophy and theology. They reflected all possible attitudes to the existence of free will: denied by hard-nosed bio-neuro-determinists; admitted as something that will emerge from complexity by biological systems researchers; demanded as a moral imperative by theologians.

Curiously, considering it is over 20 years old, a single experiment dominated our discussions. Reported in 1983 (and replicated variously) by Benjamin Libet at the University of California, San Francisco, the experiment is crucial because it seems to show we don’t have free will. Using an electroencephalogram, Libet and his colleagues monitored their subjects’ brains, telling them: “Lift your finger whenever you feel the urge to do so.” This is about as near as we get to free will in the lab.

It was already known that there is a detectable change in brain activity up to a second before you “spontaneously” lift your finger, but when did the urge occur in the mind? Amazingly, Libet found that his subjects’ change in brain activity occurred 300 milliseconds before they reported the urge to lift their fingers. This implies that, by measuring your brain activity, I can predict when you are going to have an urge to act. Apparently this simple but freely chosen decision is determined by the preceding brain activity. It is our brains that cause our actions. Our minds just come along for the ride.

Surely this must be nonsense. I know perfectly well that I am in control of my actions, particularly when it’s something as simple as moving my finger. Unfortunately there is ample evidence that we cannot rely on our personal experience in the case of action. As Thomas Metzinger, a philosopher at the University of Mainz in Germany, put it in Disorders of Volition, our experience of our own actions is “thin and evasive”.

This seems a strange thing to say, since our brains receive constant information about where our limbs are and how they are moving. This information comes from our skin, muscles and joints, as well as eyes and ears, and is critical for accurate movement. To reach for something, we need to know where we are starting from as well as where we are going.

However, this information forms a very minor part of our conscious experience. When we reach for something we are unaware of the way our fingers shape themselves to match the shape of the object we want to pick up, or of the corrections we make during the movement. All this is achieved by an automatic pilot in our brains. If we stop to think about it, we are likely to perform worse.

We even seem to be better at making complex decisions without conscious thought. In a recent experiment, Ap Dijksterhuis and his colleagues at the University of Amsterdam in the Netherlands asked people to decide which car to buy. The striking result was that people made better decisions if they were not given the chance to think about them.

These results really worry philosophers and theologians, particularly as some brain scientists argue from them that we do not have conscious control and that our actions are predetermined by the genetic make-up and environmental history embodied in our brains. Are we forced to conclude that none of us - including the most vicious criminal - is responsible for our actions? If not, is there any basis for morality?

Even if the most senior of neuroscientists tells me I have no free will, that still is not how it feels to me. The “illusion” remains as strong as ever. We can draw an analogy with visual illusions. Recall the famous Hering illusion: two vertical lines superimposed on a number of lines radiating from a point. Even though I know the vertical lines are straight, and have checked them with a ruler, I still see them as curved. There is nothing I can do about the “feeling” of them being curved. In the same way, I still feel very strongly I am controlling my actions. This feeling is real and important.

In a series of ingenious experiments, my colleague Patrick Haggard at University College London showed that the feeling of being an agent alters the way we perceive our actions. If I push a button with my finger to cause a bleep to occur 250 milliseconds later, my action and the sound it causes seem closer together in time than they really are. This mental binding of cause and effect only happens if the action is voluntary. If the finger movement that “causes” the sound is made to happen involuntarily by stimulating my brain with a magnet, the cause and its effects are pulled further apart in mental time than they are in physical time.

Perhaps the most interesting thing about the experience of being an agent is that we apply it to other people as well as ourselves. If I watch someone else push a button to cause a bleep, I can also experience their action and its consequence as being closer together than they really are. Harvard University psychologist Daniel Wegner has shown that this sense of agency we apply to ourselves and others can get confused. If two of us are controlling the same computer mouse, for example, we can easily mistake which of us is making it move.

This sense of people as agents responsible for their actions is crucial for the smooth functioning of society. Experimental economists such as Ernst Fehr at the University of Zurich in Switzerland and Simon Gächter, now at the University of Nottingham, UK, studied “miniature societies” in which groups of people play games of trust. They found that most players cooperate and return the money invested with them. But some players don’t - free riders. They make money through the cooperative behaviour of others and do not repay investments. Once free riders appear, everyone becomes less cooperative. As a result the whole group loses out. Fortunately, this can be reversed. When Fehr and Gächter let the players punish free riders with fines, free-riding decreased and cooperation increased.

Just how much we actually dislike free riders was shown by cognitive neuroscientist Tania Singer, now also at the University of Zurich. In her research, people rated free riders as less physically attractive. The dislike even showed up as brain activity in emotional regions such as the amygdala and the insular cortex. And everyone, but especially men, got a kick out of a free rider being punished.

So what has all this to do with the experience of having free will? The key is that we only dislike free riders if we perceive them as being free agents. If we are told they are just following an experimenter’s instructions then we do not dislike them and get no particular pleasure from seeing them being punished.

Personally, I like to think we do have some free will: after all, our most important way of classifying the world is into people (or agents) and things. If I don’t have free will then I am not a person. But for scientists to prove free will is not an illusion, they will have to solve the hard problem of exactly how a desire in the mental realm can cross into the physical world and cause something to happen. To date they are rather a long way from doing this.

Meanwhile, illusion or not, our feeling of being free agents has a critical role to play in regulating group interactions so that the group can benefit through cooperation. And, at the risk of not being invited to another Templeton meeting, I suggest this basic kind of morality can be found in all of us, whether or not we have religious beliefs.