When the brain goes silent: The complex reality of mind blanking

Mind blanking – those moments when our thoughts disappear and we seem to experience a pause in consciousness – is a familiar, yet surprisingly misunderstood part of human experience.

Often described as “thinking of nothing” or “feeling drowsy,” this phenomenon is now being reevaluated by scientists who believe it deserves distinct recognition in neuroscience research.

The mystery of mind blanking

In a recent opinion article, an international team of neuroscientists and philosophers compiled decades of findings on mind blanking, including recent discoveries from their own studies involving brain activity scans.

The collaboration began at the 25th Annual Meeting of the Association for the Scientific Study of Consciousness in Amsterdam in 2022, where researchers agreed that it was time to treat mind blanking not as a side effect of mind wandering, but as a separate mental state altogether.

“During wakefulness, our thoughts transition between different contents. However, there are moments that are seemingly devoid of reportable content, referred to as mind blanking,” the experts wrote. “It remains unclear what these blanks represent, highlighting the definitional and phenomenological ambiguities surrounding mind blanking.”

Exploring the phenomenon

Traditionally, mind blanking has been explored through frameworks designed to study mind wandering – the spontaneous drift of thoughts we experience throughout the day.

However, the researchers argue that mind blanking is more than just another form of daydreaming. It is often accompanied by sleepiness, sluggishness, or cognitive lapses, and deserves to be studied independently.

“We sought to better understand mind blanking by parsing through 80 relevant research articles – including some of our own in which we recorded participants’ brain activity when they were reporting that they were ‘thinking of nothing,’” explained senior author Athena Demertzi, a neuroscientist at the University of Liège in Belgium.

What the research revealed

The review offers several key insights. First, mind blanking occurs in everyone, although the frequency varies between individuals. On average, it occupies about 5% to 20% of our waking hours.

These episodes are often linked to lapses in attention, failures in memory, or a sudden halt in inner dialogue. They tend to appear more frequently during long attention-heavy tasks, after sleep deprivation, or intense physical exertion.

Children with attention deficit hyperactivity disorder (ADHD) report experiencing mind blanking more frequently than others. It is also listed as a symptom in the clinical description of generalized anxiety disorder (GAD) in the DSM-5, and appears in other neurological conditions such as strokes, seizures, traumatic brain injury, and Kleine-Levin syndrome.

Distinct changes in brain function

Studies using fMRI and EEG scans show that mind blanking is associated with distinct changes in brain function.

The phenomenon involves disruptions in the brain’s frontal, temporal, and visual networks, reduced complexity in neural signals, and what scientists refer to as “local sleep episodes” – moments when parts of the brain temporarily fall into a sleep-like state even during wakefulness.

During experiments that involved sustained mental focus, participants showed signs of mind blanking through decreased heart rate, smaller pupil size, and patterns of slow brain waves.

Meanwhile, voluntary mind clearing (like in meditation) produced deactivation in areas like the inferior frontal gyrus, Broca’s area, the supplementary motor cortex, and the hippocampus.

A framework for thoughtless moments

The research team proposes a novel framework to describe mind blanking as a collection of states influenced by physiological arousal – what they term “vigilance.”

Whether a person is in a low-arousal state (such as fatigue) or a high-arousal state (such as cognitive overload), mind blanking appears more likely to occur when the brain’s normal mechanisms for attention, memory, or speech fail to function.

“The experience of a ‘blank mind’ is as intimate and direct as that of bearing thoughts,” said co-author Jennifer Windt, a neuroscientist at Monash University in Australia.

“Our aim here is to start a conversation and see how mind blanking relates to other seemingly similar experiences, such as meditation,” added co-author Antoine Lutz from the Lyon Neuroscience Research Center in France.

The brain: Looking to the future

Ultimately, the team hopes future research will treat mind blanking as a meaningful mental state, not merely an absence of cognition. They argue it holds crucial insights for understanding attention, consciousness, and mental health.

“We believe that the investigation of mind blanking is insightful, important, and timely,” said lead author Thomas Andrillon of the University of Liège.

“Insightful because it challenges the common conception that wakefulness involves a constant stream of thoughts. Important because mind blanking highlights the interindividual differences in subjective experience. Collectively, we stress that ongoing experiences come in shades with varying degrees of awareness and richness of content.”

The study is published in the journal Trends in Cognitive Sciences.

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