Mind gone blank? Why does that happen and how is it different to daydreaming or just being inattentive?
A new research study reveals that we can spend up to 20% of our waking hours thinking about absolutely nothing at all - all conscious thought has simply stopped in its tracks, but should we be concerned?
It's happened to all of us at some time or other: we walk into the kitchen and suddenly wonder why we're there. Or we start taking an exam that we've thoroughly prepared for and then, on the second question, we suddenly feel we've forgotten everything? For a few moments our mind goes blank, completely devoid of thought, and we haven't a clue how to reverse the situation. An exhaustive study on this phenomenon, called mind blanking, was published this summer by an expert group of philosophers and neuroscientists.
As the researchers report in their paper, published in the monthly, peer-reviewed journal Trends in Cognitive Sciences, their hypothesis and approach differed from all previous ones: "Mental blocks have only been studied using tools and experiments used to analyse the phenomenon known as 'mind wandering' - when our mind suddenly thinks about something other than what is occupying us, often jumping continuously from one thought to the next." This mental wandering, explains Athena Demertzi of the University of Liège, "must be interpreted as a distinct experience from mind blanking, which makes us feel slow and erratic".
To understand once and for all the mechanisms behind a blank mind, Demertzi and her colleagues recorded the brain activity of selected subjects just as they claimed to be 'not thinking about anything', which allowed them to draw interesting conclusions. One of the main ones is that, contrary to popular belief, our minds are not constantly thinking about something. There are times when they, quite simply, lack content.
This led the researchers to consider different types of mind blanking: they can be genuine (as described above), the product of a lapse in memory, or even the result of some distraction. All of them occur spontaneously, without our consent, but deliberate mental blanks have also been shown to exist, such as those that occur during meditation or in the middle of a therapy session, when we are asked to "let our minds go blank".
What actually happens inside our brains?
Using techniques such as functional magnetic resonance imaging (fMRI - this type of scan shows which parts of our brain are most active) and electroencephalography (EEG), the study in question was also able to determine the changes that occur in the brain during an episode of mind blanking. It was observed that the electrical signals hardly change at all, just as they do when we are drowsy or in the moments right before we fall asleep. In fact, the researchers detected 'slow brainwaves' in the EEGs (typical of the so-called light sleep phase), even though the participants were fully conscious and responding to stimuli at the same time.
Another relevant finding was that all the different areas of the brain communicate much more homogeneously when the mind goes blank, making it more difficult to generate specific thoughts. According to researcher Thomas Andrillon, another of the paper's authors, there is a direct correlation between mind blanking and our level of alertness (arousal or physiological activation): the likelihood of experiencing mind blanks increases when the latter decreases or increases sharply. For example, if we have gone many hours without sleep in the first case and after an exam lasting several hours in the second, demanding our maximum concentration.
The research, funded by the University of Liège, the European Research Council, the French National Research Agency and Belgium's Fund for Scientific Research, also concluded that mind blanking is more common in clinical conditions such as attention deficit hyperactivity disorder (ADHD), generalised anxiety disorder, certain types of epilepsy or Kleine-Levin syndrome, which can cause a person to sleep up to 20 hours a day.
Be that as it may, we must understand that having the mind go blank is perfectly normal and commonplace: it is estimated that we "think about nothing" between 5% and 20% of our waking hours, a percentage that varies enormously from person to person. This, in turn, shakes up our previous understanding of consciousness: how can we be awake and aware without thinking?
Key facts about the grey matter, those "little grey cells"
Other interesting facts that demonstrate that the brain is, without a doubt, a prodigious organ:
- Brain signals travel at speeds of up to 430 km/h (the same speed as Formula 1 racing cars).
- The brain consumes 20% of our energy reserves, but accounts for only 2% of our body weight.
- Between 6,000 and 60,000 thoughts pass through our minds every day, even while we sleep, when fundamental tasks such as reorganising memory, eliminating cellular waste or regulating emotions are conducted.
- Brain connections vary from person to person depending on their experiences and habits: no two brains are alike.
- The idea that we only use 10% of our brain is wrong: its different areas are activated according to the activity at hand, so, at the end of the day, we are fully using it.
