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A new study reveals we're all a little bit delusional

Delusions have a lot in common with feelings of déjà vu. 

Imagine that on your way to the shops, you have a sudden feeling that it's about to rain, and voila - it starts to rain! 

Did you just predict the future? What if you believed that you did? Does that make you delusional?

According to scientists at Yale, the answer is, perhaps, at least a little bit. That's the premise of a new paper on the science of delusion and psychosis in the Proceedings of the National Academy of Sciences.

The scientists were trying to determine whether there was a relationship between delusion and what is called a "postdiction" paradigm - when people mistake a prediction for something that has already happened. 

The experiment the study is based on is deceptively simple. Participants were asked to look at five randomly-spaced white squares on a screen. One square, at any time, would then become red. The participant was asked, when looking at the white squares to guess which square they believed would become red.

As the square becoming red was completely random, the participant had a one in five chance of predicting the square correctly. The participants were then asked to report to the researchers whether they had predicted correctly.

The scientists could control when the random white square would turn red. If the white square turned red within 250 milliseconds, the participants were more likely to say they had made an accurate prediction. If the white square changed colour after 250 milliseconds, the participants reported accurate predictions - ie they were right one out of five times.  

So what's so special about the white square changing colour within 250 milliseconds?

This phenomenon is called an “illusory reversal of thought”. The square is actually already changing colour while the participants are making their prediction. They think they have correctly guessed which square has changed colour, but actually their subconscious has just processed which square changed colour. The participants, though, believe that they have made a prediction.

As Dr Adam Bear, the lead author of the paper tells me, "a perceptual event that seems to occur later in consciousness (a square turning red) biases a prediction that's experienced earlier in time". 

In other words, did you really predict that it would rain, or did you first subconsciously feel rain drops, and then consciously make the prediction that it would rain? You didn't guess that it would rain! It was already raining, and it just took you a while to realise. 

Bear compares it to the "experience of déjà vu" . You might feel like you are anticipating everything that is happening in the moment. "But that's only because a subconscious memory system has already processed what's going on and that information hasn't yet reached your consciousness." 

The participants were also asked to complete a 21 item Delusions Inventory (PDI) questionnaire which measures a person’s tendency to be delusional. It asks such questions as whether “you ever feel as if people are reading your mind?”

While most people will resolutely answer "No", it should be noted that psychosis is a continuum. We are all prone to a few delusional ideas - just look at Donald Trump.

In the experiment, those who more likely to say that they had predicted which square would change colour correctly (when in fact they had just observed the square change colour), were also more likely to score higher on the Delusions Inventory.

Bear says that believing these types of errors are the "kind of thing you might expect would predict certain delusional beliefs, particularly about clairvoyance, telepathy and grandiosity".

This effect could be due to a number of reasons. Studies have shown that those who are more prone to delusions are more ready to jump to conclusions based on weak evidence. This perceptual timing illusion may accentuate delusions of control. 

The latter is best explained by our inability to tickle ourselves, as our brain knows the action is self-initiated. This is the case even if a robot arm mimics your actions and tries to tickle you - it can't. Your brain knows who's in ultimate control. Scientists think we laugh when tickled in order to diffuse the tension and show our tickler that we submit. 

However, a robot arm can tickle you - so long as you delay its action after you have instructed it what to do. This delay makes the brain think the robot arm is not under your control. Timing is everything. 

The scientists hope that if these types of errors are more present in people before they start expressing delusions, their five white squares test could be used to identify those at risk of psychosis. This could be a very significant achievement. Not only is the test inexpensive, it can also be done easily online. The earlier people are identified, in psychosis especially, the more effective intervention treatments can be.

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Tackling tuition fees may not be the vote-winner the government is hoping for

In theory, Theresa May is right to try to match Labour’s policy. But could it work?

Part of the art of politics is to increase the importance of the issues you win on and to decrease or neutralise the importance of the issues your opponent wins on. That's part of why Labour will continue to major on police cuts, as a device to make the usually Labour-unfriendly territory of security more perilous for the Tories.

One of the advantages the Conservatives have is that they are in government – I know it doesn't always look like it – and so they can do a lot more to decrease the importance of Labour's issues than the Opposition can do to theirs.

So the theory of Theresa May's big speech today on higher education funding and her announcement of a government review into the future of the university system is sound. Tuition fees are an area that Labour win on, so it makes sense to find a way to neutralise the issue.

Except there are a couple of problems with May's approach. The first is that she has managed to find a way to make a simple political question incredibly difficult for herself. The Labour offer is “no tuition fees”, so the Conservatives essentially either need to match that or move on. But the one option that has been left off the table is abolition, the only policy lever that could match Labour electorally.

The second, even bigger problem is that it it turns out that tuition fees might not have been the big election-moving event that we initially thought they were. The British Electoral Survey caused an earthquake of their own by finding that the “youthquake” – the increase in turn-out among 18-24-year-olds – never happened. Younger voters were decisive, both in how they switched to Labour and in the overall increase in turnout among younger voters, but it was in that slightly older 25-35 bracket (and indeed the 35-45 one as well) that the big action occurred.

There is an astonishingly powerful belief among the Conservative grassroots, such as it is, that Jeremy Corbyn's NME interview in which the he said that existing tuition fee debt would be “dealt with” was decisive. That belief, I'm told, extends all the way up to May's press chief, Robbie Gibb. Gibb is the subject of increasing concern among Tory MPs and ministers, who regularly ask journalists what they make of Robbie, if Robbie is doing alright, before revealing that they find his preoccupations – Venezuela, Corbyn's supposed pledge to abolish tuition fee debt – troublingly marginal.

Because the third problem is that any policy action on tuition fees comes at a huge cost to the Treasury, a cost that could be spent easing the pressures on the NHS, which could neutralise a Labour strength, or the financial strains on schools, another area of Labour strength. Both of which are of far greater concern to the average thirtysomething than what anyone says or does about tuition fees.

Small wonder that Team Corbyn are in an ebullient mood as Parliament returns from recess.

Stephen Bush is special correspondent at the New Statesman and the PSA's Journalist of the Year. His daily briefing, Morning Call, provides a quick and essential guide to domestic and global politics.