Mind blanking is a distinct mental state
A new paper co-authored by Action researchers has just been published in PNAS: “Mind blanking is a distinct mental state linked to a recurrent brain profile of globally positive connectivity during ongoing mentation”.
Traditionally, it is believed that our minds are constantly filled with different thoughts and ideas; however, this stance is challenged by what scientists call mind blanking, and research proves there are moments during our conscious experience when we have the impression that our minds are empty. We had a chance to talk to Sepehr Mortaheb, PhD (first author) and Athena Demertzi, PhD (supervising scientist), who co-authored this paper, which has just been published in PNAS. These scientists work at GIGA CRC-In Vivo Imaging, Physiology of Cognition Lab at the University of Liège.
What is mind blanking? How would you explain this phenomenon to a non-scientist? Athena Demertzi, PhD and Sepehr Mortaheb, PhD: Imagine that you are sitting somewhere doing nothing. Your mind is active from time to time, remembering things that have happened, planning things for the future, or it is just captured by things that are happening at the moment. Sometimes, though, you’re not thinking about anything at all.
For example? AD, SM: You recall a party you went to last week, then you think about a meeting you had the following day, then you hear a noise which draws your attention. There are also moments when someone interrupts you and asks about your thoughts. You may feel as though you have nothing in your mind, or you are unable to recall what you were thinking. In other words, your mind has simply gone blank. We call these moments “mind blanking”.
But what makes mind blanking an interesting research topic? AD, SM: Traditionally, it is believed that our minds are constantly filled with different thoughts and ideas. This view is challenged by mind blanking as it demonstrates that there are moments during which our conscious experience can be devoid of mental contents.
How is this linked with COST Action’s research objectives? AD, SM: As mind blanking happens during typical wakeful life, studying it can help us better understand the ongoing conscious experience and how our brain produces this experience. In that sense, it fits perfectly with COST Action’s consciousness-related research objectives in the context of learning and memory. Indeed, we do not yet have an explanatory account for mind blanking. Multiple questions still remain unanswered: Could it be due to memory recollection failures? Could it be caused by inattentiveness to the stream of thought? Or might it be a result of the epiphenomenon of lapses in cognitive control? If one shows too many mind blanking instances during a new learning task, what would that mean for performance?
Another exciting aspect of mind blanking is that it challenges the limits of thoughts, whether they be visual, auditory, olfactory, mental images, etc. It creates a unique case of “wakeful unconsciousness”, during which people can report on their ongoing experiences. At the same time, we can characterize it and test it from a third-person perspective.
How does MRI scanning look from a participant’s point of view? When I’m lying in a scanner, what do you ask me to do? To study ongoing experience using functional MRI, we use a method called “experience sampling”. In this setting, you lie still in the MRI scanner looking at an empty screen and doing nothing in particular. In this way, the mind can freely wander from time to time and from place to place. At random points, you will get interrupted by an auditory beep inviting you to report your mental state by pressing the appropriate buttons on a response box you are holding.
The participants in this study had to choose their mental state from four primary categories: from stimulus-independent thoughts to absence of thoughts. This method allowed us to investigate how the brain was functioning when participants reported mind blanking.
Did we learn anything new? In this study, we found that when participants reported mind blanks, many brain regions were highly synchronized, as evidenced by globally positive functional connectivity. At the same time, we found that the average fMRI BOLD signal had a significantly larger amplitude during mind blanking instances. What I mean is that if we look at the brain signal from each brain region and we take its average, we will see that this fluctuates with higher amplitude. Previous research shows that this higher amplitude is related to low-frequency waves passing through the brain (also known as slow-wave activity). These waves are indicative of neural silencing across the brain.
I’m lost… Simply put, there are moments during wakefulness when a wide range of neurons across the brain become dormant. This might manifest behaviorally as mind blanking. We already know that mind blanks can happen as a result of cognitive overload when performing demanding tasks. For example, they can occur when you do a Sustained Attention to Response Task (a go/no-go task that requires participants to withhold behavioral response to a single infrequent target (often number 3) presented amongst a background of frequent non-targets (0-2, 4-9)); in other words, a very boring and demanding task. What’s new here is the finding that there is no need to induce, trigger, or observe mind blanking: it can also happen spontaneously in particular individuals, e.g., monks who practice meditation to empty their minds. In other words, mind blanking is another default mental state. Why our brain needs to be set up like this during wakefulness is a question that still needs to be addressed.
Do these findings have any potential applications in clinical practice? Generally, the better we comprehend the relationship between the brain and the mind, the more effective procedures we can develop in clinical practices. To be more specific about mind blanking, previous research revealed that several disorders, such as ADHD and depression, are associated with increased reports of mind blanking instances. Therefore, a more profound comprehension of mind blanking and its neural counterpart in the brain may improve our understanding of such disorders and potentially lead to more effective treatments.
