Gravity holds not only the body but also the mind — what happens when it disappears

Until now, this has been attributed to poetic exaggeration or a psychological reaction to an extreme experience.

A new scientific study, published in the journal Frontiers in Psychology, offers a different explanation: it’s all down to gravity. Or rather, the lack of it.

According to the authors, over thousands of years the human brain has structured its perception of reality around gravity as the main point of reference. Remove it, and consciousness is forced to rebuild itself from scratch.

An important caveat: this is a theoretical review paper, not a new experiment. The authors have collated and reinterpreted data from existing studies, proposing a new conceptual framework. The conclusions are interesting but require verification in future experiments.

Details

Let’s start with how the brain generally understands where the body is. The inner ear constantly tells the brain where ‘down’ is. This signal is so stable and constant that the brain stops noticing it — it simply takes gravity for granted and incorporates it into its basic expectations of how the world works. Scientists call this a ‘superprior’ — that is, the strongest and most reliable background assumption on which all other perception is based.

In weightlessness, this signal disappears. The brain receives conflicting data: the inner ear is silent, whilst the body behaves unusually. A chain of ‘prediction errors’ begins — the brain tries again and again to reconcile what it expected with what it feels, and cannot. It has to literally rewrite its understanding of reality.

It is precisely this, according to the authors, that gives rise to those strange states described by astronauts. In the early stages — disorientation and nausea: the brain panics. Then comes gradual adaptation, but with it comes a blurring of the familiar boundaries between ‘oneself’ and ‘the world around’. The sense of one’s body becomes unstable. Perception of space changes.

And sometimes this reveals something unexpected. Many cosmonauts describe the so-called ‘overview effect’ — a sudden sense of awe and unity at the sight of Earth from space. The fragile blue planet against the backdrop of darkness triggers an immediate re-evaluation of values, ecological concern and a profound sense of connection with humanity. The same mechanism that causes disorientation apparently also opens the door to unusual states of consciousness.

This is confirmed by physical data. Brain scans taken before and after long-duration missions reveal real changes: fluid in the head is redistributed, the brain’s ventricles enlarge, and the volume of grey matter in certain areas changes. Neural networks are reorganised. The brain’s default mode network — the one associated with self-awareness and internal dialogue — temporarily weakens. Electroencephalography records a decrease in alpha rhythms, which is usually associated with increased excitability and a weakening of internal inhibitory mechanisms.

The authors draw attention to the similarity of this pattern to what happens in the brain under the influence of psychedelics — such as LSD or psilocybin. In both cases, the brain becomes less hierarchical, its regions begin to communicate more freely with one another, and the usual frameworks of perception weaken. But it is important not to confuse the two: this does not mean that weightlessness and drugs are one and the same. We are talking about a similar computational outcome resulting from different causes.

Why this is important

Understanding how gravity shapes consciousness is important in several ways.

Firstly, there is a practical aspect. Commercial space travel is developing rapidly, and in the coming years thousands of people without special training will find themselves in weightlessness. If altered states of perception are not a coincidence but a predictable neurocognitive effect, we need to prepare for this in advance.

The second is scientific. Space offers a unique ‘natural laboratory’ for studying consciousness: it removes one of the most fundamental factors shaping perception, without any chemical intervention. This opens up new possibilities for neuroscience.

Thirdly, there is a therapeutic aspect. The authors cautiously suggest that controlled manipulations of gravitational perception — for example, via special simulators or virtual reality — may one day be used to treat conditions associated with ‘stuck’ thinking, such as depression or PTSD. But this is still a vision of the future, not a ready-made therapy.

Background

The science of consciousness is one of the most complex and controversial fields. We still do not fully understand how physical processes in the brain give rise to subjective experience. This new work fits into a growing tradition of studying consciousness through ‘natural experiments’ — situations where familiar conditions change radically, allowing us to see what is normally hidden.

The overview effect as a psychological phenomenon has long been described, but until now has lacked a convincing neurobiological explanation. Parallels with psychedelic states have also been discussed in science in recent years — as research into psilocybin and LSD returns to the legitimate scientific arena.

The work was carried out by a team led by Anahita Nezami and published in the peer-reviewed journal Frontiers in Psychology. However, this is specifically a theoretical review, not the result of a new experiment — the authors themselves call for their ideas to be tested in future studies on real missions.

Source

Annahita Nezami et al., ‘Space Oddity: microgravity as a neurocognitive catalyst for transformative consciousness experiences’, Frontiers in Psychology (2026).