Hidden powers: 6 amazing things your unconscious mind can do

THINK you know what’s going on in your mind? You must be kidding. Much of our mental life happens in the unconscious: a place that Freud famously considered to be a cesspit of our most basic animalistic desires. This is a view that modern neuroscientists definitely don’t share, but they do agree with Freud on one thing – that our brains have an uncanny knack for working stuff out, with no need for conscious involvement. So how do the thoughts you don’t know you’re having run your life? Is it possible to bring those murky machinations to the surface for closer inspection? New Scientist investigates.

Fast asleep? Your unconscious is still listening
Some people swear that if they want to wake up at 6 am, they just bang their head on the pillow six times before going to sleep. Crazy? Maybe not. A study from 1999 shows that it all comes down to some nifty unconscious processing.

For three nights, a team at the University of Lubeck in Germany put 15 volunteers to bed at midnight. The team either told the participants they would wake them at 9 am and did, or told them they would wake them at 9 am, but actually woke them at 6 am, or said they would wake them at 6 am and did.

This last group had a measurable rise in the stress hormone adrenocorticotropin from 4.30 am, peaking around 6 am. People woken unexpectedly at 6 am had no such spike. The unconscious mind, the researchers concluded, can not only keep track of time while we sleep but also set a biological alarm to jump-start the waking process. The pillow ritual might help set that alarm.
The sleeping brain can also process language. In a 2014 study, Sid Kouider of the École Normale Supérieure in Paris and his colleagues trained volunteers to push a button with their left or right hand to indicate whether they heard the name of an animal or object as they fell asleep. The team monitored the brain’s

Don’t think: How your brain works things out all by itself
Wouldn’t it be great if you could leave difficult decisions to your subconscious, secure in the knowledge that it would do a better job than conscious deliberation? Ap Dijksterhuis of Radboud University Nijmegen in the Netherlands proposed this counter-intuitive idea 12 years ago. No wonder it was instantly popular.

Dijksterhuis had found that volunteers asked to make a complex decision – such as choosing between different apartments based on a baffling array of specifications – made better choices after being distracted from the problem before deciding. He reasoned that this is because unconscious thought can move beyond the limited capacity of working memory, so it can process more information at once.

The idea has been influential, but it may be too good to be true. Many subsequent studies have failed to replicate Dijksterhuis’s results. And a recent analysis concluded that there is little reason to think the unconscious is the best tool for making complex decisions.

Still, Dijksterhuis remains confident that the effect is real and is an important part of our mental toolkit.

We accurately weigh up a person’s character in 0.1 seconds
Ever felt love at first sight? Or an irrational distrust of a stranger on a bus? It could be because our unconscious is constantly making fast judgements. And they are often pretty accurate.

In the early 1990s Nalini Ambady and Robert Rosenthal, both then at Stanford University in California, asked volunteers to rate teachers on traits including competence, confidence and honesty after watching 2-, 5- or 10-second silent clips of their performance. The scores successfully predicted the teachers’ end of semester evaluations and 2-second judgements were as accurate as those given more time. Further experiments showed similar accuracy for judgements about sexuality, economic success and political affiliation. For anyone hoping to use this to their advantage, the bad news is that no one has worked out what to do to pass yourself off as a winner. It seems to be an overall body signal that is both given out and picked up unconsciously, and is greater than the sum of its parts. This makes it very difficult if not impossible to fake.

Your brain’s crystal ball helps you understand speech and fear
Every moment, the brain takes in far more information than it can process on the fly. In order to make sense of it all, the brain constantly makes predictions that it tests by comparing incoming data against stored information. All without us noticing a thing.

Simply imagining the future is enough to set the brain in motion. Imaging studies have shown that when people expect a sound abstract or image to appear, the brain generates an anticipatory signal in the sensory cortices.

This ability to be one step ahead of the senses has an important role in helping us understand speech. “The brain is continuously predicting the sounds, words and meanings that people are trying to produce or communicate,” says Matt Davis at the MRC Cognition and Brain Sciences Unit in Cambridge, UK.

“We only notice an object once our unconscious has calculated its importance“
Studies have also shown that the brain can use one sense to inform another. When you hear a recording of speech that is so degraded it is nearly unintelligible, the words sound clearer if you have previously read the same words in subtitles. “The sensory parts of the brain are comparing the speech you’ve heard to the speech you predicted,” says Davis.