Presence and the brain: why does the mere presence of others alter our internal state?
- drissboussaoud
- 3 days ago
- 8 min read
Remember that very simple moment. You arrive in a quiet, somewhat empty place, and you don't yet know if it's actually occupied or not. Almost immediately, one question dominates your mind: is there someone else here, or am I alone?
This question may seem trivial. Yet it reveals something profound about how we function. Even before analyzing the situation, even before knowing what we're going to do, a part of us is already assessing the context of presence. Are we alone? Is someone there? Is this presence close, reassuring, unfamiliar, or potentially threatening?
In other words, our brain doesn't just process a place, a task, or a time. It also processes, very quickly, whether we are alone or in the presence of others. And this information already changes something within us: our alertness, our physical tension, our sense of security, our way of perceiving the environment, sometimes even our way of thinking.
We often tend to believe that others only influence our inner state when they speak to us, judge us, help us, or threaten us explicitly. However, the reality is more subtle. The mere presence of another human being can be enough to alter our inner state.
Presence, therefore, is not simply a backdrop. It is not a neutral setting against which our thoughts and emotions unfold. It often acts as a condition of the experience itself .
We do not do the same things alone or with others
One only needs to observe daily life to see how subtly the presence of others changes our way of being in the world.
A child doesn't play in exactly the same way depending on whether a reassuring adult is present or not. A student doesn't achieve the same level of attention when working alone at home as when they are in a quiet library, surrounded by others. A speaker doesn't speak in the same way in an empty room as in front of an audience. An athlete, a musician, a therapist, a teacher—all know from experience that the presence of others can sometimes support, sometimes stimulate, sometimes hinder, and sometimes destabilize.
What's striking is that this change can occur even without direct interaction. It's not always necessary for someone to speak to us, look at us, or explicitly evaluate us for something within us to shift. The mere presence of another person can be enough to transform our inner state.
The body no longer engages in quite the same way. Vigilance shifts. Attention becomes more focused, tense, or dispersed. A certain kind of momentum may emerge, or conversely, a movement of withdrawal. In some cases, presence seems to support internal organization; in others, it introduces tension or caution.
This means that the brain does not just process a task, an emotion or a situation “in itself”. It also processes it in an implicit relational environment, that is to say in a situation where there are, or are not, other presences, and where these presences already have meaning.
Presence doesn't need to be spectacular to be active
We often pay attention to overt interactions: an argument, a comforting gesture, a critical look, a kind word. But the influence of presence begins long before these visible events.
Someone is there. They say nothing. They don't intervene. They exert no apparent pressure. And yet, our state can already change. We may feel a little safer, a little more alive, a little more supported. But we can also become more vigilant, more tense, more cautious, or more inhibited.
This subtle influence is important because it shows that the presence of others does not merely act as content within experience; it also acts as a fundamental condition of experience. It shapes how a situation is experienced even before we begin to consciously analyze it.
This is one of the reasons why some situations are so difficult to explain in purely rational terms. A person might say, “I don’t know why, but when he’s around, I don’t feel the same.” Or conversely, “When that person is present, I calm down almost effortlessly.” These statements are often very accurate. They describe a real change in one’s internal state, even if the underlying mechanisms remain partly implicit.
The brain is constantly evaluating the context
Why does the presence of others have such an effect? Because the brain is not simply an organ that processes abstract information. It is also an organ that constantly evaluates the context in which we find ourselves.
Can I let go? Should I keep watch? Am I safe? Should I prepare to act? Can I explore, feel, think freely, or is it better to remain cautious?
These adjustments don't always occur consciously. They are often rapid, automatic, rooted in a person's history and how their system has learned to interpret the world. The presence of others is one of the most important signals in this contextual interpretation.
Depending on the situation, the quality of the relationship, shared history, and current state of mind, a presence can be interpreted as support, a resource, protection, or conversely, as a constraint, an uncertainty, a potential threat. This is why presence is never neutral. It always involves, to varying degrees, an evaluation of the context.
From this perspective, we can say that presence becomes an organizing variable . It does not simply add a relational element to an already established experience. It participates in how this experience will be structured from the outset.
This intuition doesn't stem solely from everyday experience or clinical observation. It also resonates with experimental work conducted within our team. A CNRS press release published in 2017 concerning the work of Marie Demolliens already demonstrated that, in macaques, different prefrontal neurons are activated for the same task depending on whether a conspecific is present or absent. More recently, an Inserm press release dedicated to our 2025 research showed that the mere presence of others, even in the absence of direct interaction, can be associated with an increase in the efficiency of excitatory synapses in brain regions involved in attention and behavioral adjustment, such as the dorsolateral prefrontal cortex and the anterior cingulate cortex. ( cnrs.fr )
In other words, the presence of others does not merely act as a psychological or relational context. It also seems to penetrate the very mechanisms by which the brain adjusts its activity, attention, and learning methods. ( Inserm pro )
Some presences soothe, others activate
One of the most telling aspects of this reality is that not all presences produce the same effect. We know this intuitively. Some people allow us to relax almost immediately. Their way of being there, their tone, their stability, their clarity, their quiet warmth alter the inner atmosphere. In their presence, it becomes easier to breathe, to think, to feel without tensing up.
Other presences, on the contrary, put us on high alert. Sometimes overtly, because they are intrusive, unpredictable, critical, or invasive. But sometimes also in a much more subtle way. A certain rigidity sets in, a diffuse vigilance appears, the body prepares silently. Something within us shuts down, tenses, or withdraws.
It's not simply a matter of like or dislike in the ordinary sense. What's at stake is often deeper: how our system interprets what this presence represents. Is it an environment in which I can be more myself? A presence I can rely on? Or, on the contrary, a situation in which I must remain cautious, controlled, protected?
Thus, the presence of others can be regulating, but it can also be activating or disorganizing. It can help contain emotion, or on the contrary, make it more difficult to tolerate. It can support momentum, or provoke withdrawal.
What this changes in our thinking about stress
This idea becomes particularly illuminating when we consider stress. We often talk about stress as if it were simply an individual's response to an objective difficulty. However, how a situation is experienced also depends heavily on the relational context in which it arises.
The same ordeal doesn't cost the same depending on whether you face it alone or with others. An anxious wait, a professional difficulty, uncertainty, speaking in public, a moment of vulnerability can become more bearable when a sufficiently reassuring presence is there. Conversely, a relatively neutral situation can become distressing if the surroundings are perceived as tense, ambiguous, or threatening.
In other words, stress does not depend solely on the situation itself. It also depends on the conditions under which the brain and body must cope with that situation.
This helps explain why some people seem more comfortable in objectively demanding contexts, while others can be deeply destabilized by seemingly mundane situations. The level of external difficulty doesn't explain everything. We must also consider how the system interprets the human environment.
Presence and trauma: when the system no longer reads the context in the same way
This perspective becomes even more important when considering trauma. In the aftermath of traumatic experiences, it is not only the memory of a past event that remains active. Often, the entire system becomes more sensitive to certain signals, more cautious, more reactive, or conversely, more inclined towards withdrawal and dissociation.
In this context, the presence of others can become much more difficult to interpret. An objectively benevolent presence can be perceived as too close, too intense, too difficult to read, or even potentially threatening. Conversely, some people may intensely seek the proximity of another in an attempt to regain a sense of security, without always being able to fully rely on it.
This shows that presence never acts in a purely abstract way. Its effect depends on how the system perceives it. For some people, being with someone immediately reduces internal stress. For others, it increases the effort required to stay organized.
Understanding this changes a lot. It allows us to move beyond an overly simplistic interpretation of human reactions. A person who tenses up, shuts down, dissociates, becomes agitated, or withdraws in the presence of others is not necessarily overreacting. Their system may simply be doing what it has learned to do to preserve its integrity.
Another way of thinking about emotional regulation
We often talk about emotional regulation as a personal skill: learning to breathe, taking a step back, identifying one's emotions, and better managing one's reactions. All of this is essential. But this view remains incomplete if we forget that regulation also depends, in part, on the context in which the person finds themselves.
We do not regulate our emotions in the same way depending on whether we are alone, accompanied, supported, or in the presence of an uncertain human environment. Some presences lighten the work of regulation. Others make it more difficult.
This does not mean that emotional regulation is solely relational. Rather, it means that it is always situated . It is never entirely independent of the human environment in which the brain and body operate.
This idea is important because it allows us to think more deeply about what is at play in close relationships, in stressful situations, in attachment, and of course in psychotherapy. It invites us to consider that our internal state is not constructed solely from internal mechanisms, but also from the way in which the presence of others shapes our experience.
Conclusion: The brain of presence
The mere presence of others can change far more than we imagine. It can alter our alertness, our sense of security, our physical tension, our capacity to think, to feel, to open up or to protect ourselves. It can support our internal organization, or conversely, weaken it.
Understanding this leads us to take presence seriously. Not as a mere relational backdrop, but as a fundamental dimension of human experience. We don't function the same way when we're alone as when we're with others, and this difference isn't just due to what others say or do. It also stems from the fact that their presence already alters the conditions under which our brain evaluates, feels, and acts.
Ultimately, it comes down to asking a simple but crucial question: what if the brain never functions entirely on its own?
To go further
You can continue this discussion with these other blog articles:
Why the brain isn't designed to carry everything on its own: The Social Baseline Theory explained simply
EMDR, presence and regulation: what really happens in therapy
References and further reading
CNRS. From context to cortex: discovering social neurons , press release, 2017. ( cnrs.fr )
Inserm Pro. Influence of social presence on the brain: more efficient synapses , December 2, 2025. ( Inserm pro )
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