{"id":2070,"date":"2026-08-16T10:21:26","date_gmt":"2026-08-16T10:21:26","guid":{"rendered":"https:\/\/driss-boussaoud.rovexen.com\/?p=2070"},"modified":"2026-09-02T05:53:08","modified_gmt":"2026-09-02T05:53:08","slug":"la-presence-avant-le-cerveau","status":"publish","type":"post","link":"https:\/\/driss-boussaoud.rovexen.com\/en\/la-presence-avant-le-cerveau\/","title":{"rendered":"PRESENCE BEFORE THE BRAIN"},"content":{"rendered":"<h2 class=\"wp-block-heading\">The biological roots of sociality\u2026<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Has the presence of others influenced living things for longer than the brain itself? From bacteria capable of detecting the density of their neighbors to human brain networks sensitive to social presence, a central hypothesis of the Presence Brain project is emerging: sociality does not begin with interaction, but with the ability to detect that others are there.<\/h3>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/static.wixstatic.com\/media\/23438d_fde797c416c649548e0caa048f9a6c9e~mv2.png\/v1\/fill\/w_740,h_493,al_c,q_90,usm_0.66_1.00_0.01,enc_avif,quality_auto\/23438d_fde797c416c649548e0caa048f9a6c9e~mv2.png\" alt=\"La sensibilit\u00e9 \u00e0 la pr\u00e9sence, un ph\u00e9nom\u00e8ne biologiquement pertinent \u00e0 travers l'\u00e9volution, avant m\u00eame l'apparition des neurones, du syst\u00e8me nerveux et du cerveau. \"\/><figcaption class=\"wp-element-caption\">Sensitivity to presence, a biologically relevant phenomenon throughout evolution, predates even the appearance of neurons, the nervous system, and the brain. Quorum sensing in bacteria reappears in different forms in social insects, fish, mammals, and then in humans.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Most theories of the social brain begin with interaction. Some begin with the brain itself. They seek to understand how organisms perceive their conspecifics, communicate with them, cooperate, or build relationships.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The Brain of Presence project  leads to a more radical question: what if sensitivity to the presence of others was older than the brain itself? <em>The Brain of Presence:<\/em>&nbsp;conduit \u00e0 poser une question plus radicale : et si la sensibilit\u00e9 \u00e0 la pr\u00e9sence des autres \u00e9tait plus ancienne que le cerveau lui-m\u00eame ?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">We spontaneously tend to consider presence as a psychological phenomenon, or even as a conscious experience. Yet, if we go back far enough in the history of life, another possibility emerges. Before being a lived experience, before being a cerebral mechanism, presence could be a fundamental biological fact.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Is anyone there?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">To explore this idea, let's imagine a marine bacterium.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">It possesses neither a brain, nor a nervous system, nor consciousness in the way we usually understand it. Yet, it is capable of modifying its behavior depending on the number of other bacteria present in its environment. When the density of neighboring organisms reaches a certain threshold, it changes the expression of its genes, adapts its survival strategies, and behaves differently depending on whether it is alone or surrounded.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This mechanism is known as quorum sensing . <em>quorum sensing<\/em>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Each bacterium constantly releases small chemical molecules into its environment. As the number of bacteria increases, the concentration of these molecules also increases\u2014a continuous, chemical estimate of the density of its kind, rather than a simple count. When a critical threshold is reached, the entire population changes its behavior in a coordinated manner\u2014but this collective coordination relies on information that has never stopped gradually changing.  (Miller &amp; Bassler, 2001)<strong>&nbsp;(Miller &amp; Bassler, 2001)<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The bacterium does not directly perceive its neighbors. It perceives their trace. But this trace is enough to inform an estimation, more or less strong depending on the perceived concentration: is someone there? And this estimation modifies what the bacterium does. <strong>quelqu\u2019un est-il l\u00e0 ?<\/strong> Et cette estimation modifie ce que la bact\u00e9rie fait.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">This is not a metaphor<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Il serait tentant de consid\u00e9rer le <em>quorum sensing<\/em>&nbsp;It would be tempting to consider quorum sensing  as a simple analogy for presence. However, that would be to miss the point entirely.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Le <em>quorum sensing<\/em>&nbsp;Quorum sensing  is not a metaphor for presence. It is a presence detection mechanism. It allows an organism to adjust its behavior based on the presence of other organisms.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This mechanism has been preserved by evolution because it confers a decisive advantage. In certain situations, survival depends precisely on the ability to take into account the presence of others.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In very different forms, this principle reappears throughout the history of life. A single idea seems to run through evolution: the presence of others constitutes biologically relevant information. And this information modifies behavior.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">The brain did not invent presence<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">This perspective leads us to look at the brain from a slightly different angle.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">We often tend to think of the brain as the origin of sociality. However, it may be more accurate to say that it inherited much older mechanisms.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><em>The brain did not invent sensitivity to presence. It transformed it. It amplified it. It integrated it into ever more complex forms of information processing.<\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In social insects, the presence of conspecifics organizes sophisticated collective behaviors. In fish, it regulates school cohesion and responses to predators. In rodents, it influences learning, risk-taking, and stress regulation\u2014effects documented in studies on social facilitation and the presence of an observer. In primates, it shapes social behaviors, observation of others, and the acquisition of new skills.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">These effects are not anecdotal. They reveal a remarkable functional continuity: at each level of complexity of living organisms, the presence of others constitutes information that modifies the organism's behavior. It is this continuity that the Brain of Presence project  seeks to formalize, down to the finest levels of human brain organization. <em>The Brain of Presence:<\/em>&nbsp;cherche \u00e0 formaliser, jusqu\u2019aux niveaux les plus fins de l\u2019organisation c\u00e9r\u00e9brale humaine.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In humans, social presence penetrates to the finest levels of brain organization\u2014from synaptic mechanisms to the large networks involved in attention, emotions, and social cognition.  \"Social\" and \"asocial\" prefrontal neurons have thus been identified in non-human primates (Demolliens et al., 2017), and effects have been observed at different levels of neuronal organization (Esmaeili et al., 2025; Tricoche et al., 2025).<strong>&nbsp;<\/strong>Des neurones pr\u00e9frontaux \u00ab&nbsp;sociaux&nbsp;\u00bb et \u00ab&nbsp;asociaux&nbsp;\u00bb ont ainsi \u00e9t\u00e9 identifi\u00e9s chez le primate non-humain (Demolliens et al., 2017), et des effets ont \u00e9t\u00e9 observ\u00e9s \u00e0 diff\u00e9rents niveau de l&rsquo;organisation neuronale (Esmaeili et al., 2025; Tricoche et al., 2025).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Between the bacterium that chemically detects the density of its neighbors and the human being who instantly perceives that they are not alone in a room, billions of years of evolution have passed. But a continuity remains. At each stage, organisms have had to answer the same question: Is anyone there? <em>Y a-t-il quelqu\u2019un ?<\/em><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">An evolving continuity<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">We often tend to view sociality as a complex property that appeared relatively late in the history of life, thanks to intelligence, language, or consciousness. This intuition is understandable. The most elaborate forms of communication and cooperation do indeed seem to depend on sophisticated cognitive abilities.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">But this perspective could lead us to overlook something more fundamental.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">What if what we now call social cognition, attachment, cooperation, or communication was based on a much older principle?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">What if all these abilities stemmed from a more basic property: the capacity to detect the presence of other organisms and adjust one's behavior accordingly? From this perspective, sociality would not begin with interaction. It would begin with presence.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What this changes<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">This hypothesis profoundly transforms the initial question.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">If sensitivity to presence is a biological mechanism conserved for billions of years \u2014 before the nervous system, before the brain, before consciousness \u2014 then it is not a late consequence of social cognition. It may well be its very foundation.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Communication, cooperation, empathy, or theory of mind then appear as progressive elaborations of a more fundamental property: the ability to detect that other organisms are present and to adjust one's behavior accordingly.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Before speech. Before thought. Before even the brain. There was already presence. Perhaps understanding presence, then, is not simply understanding a dimension of the human brain. It is understanding one of the most ancient roots of sociality. It is perhaps also understanding one of the oldest and most enduring properties of life.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">References<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Demolliens, M., Isbaine, F., Takerkart, S., Huguet, P., &amp; Boussaoud, D. (2017). Social and asocial prefrontal cortex neurons: A new look at social facilitation and the social brain. Social Cognitive and Affective Neuroscience, 12(8), 1241\u20131248.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Esmaeili, A., Demolliens, M., Viersen, M., et al. (2025). Probabilistic inference of social presence across brain scales reveals enhanced synaptic efficacy. Communications Biology, 8, 1608.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tricoche, L., Royer d\u2019Halluin, M., Meunier, M., et al. (2025). Neural bases of social facilitation and inhibition: How peer presence affects elementary eye movements. Soc. Cogn. Affect. Neuroscience. , 20, nsae079. <em>Soc. Cogn. Affect. Neurosci.<\/em>, 20, nsae079.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Miller, M.B., &amp; Bassler, B.L. (2001). Quorum sensing in bacteria. Annual Review of Microbiology, 55, 165\u2013199.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Articles and links to explore<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\"><u><a href=\"https:\/\/driss-boussaoud.rovexen.com\/en\/les-dimensions-de-la-presence\/\" target=\"_blank\" rel=\"noreferrer noopener\">The Brain of Presence:<\/a><\/u><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">General presentation of the project and the question that constitutes its starting point.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><u><a href=\"https:\/\/driss-boussaoud.rovexen.com\/en\/le-cerveau-social\/\" target=\"_blank\" rel=\"noreferrer noopener\">The social brain: an incomplete revolution<\/a><\/u><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">How social neuroscience has transformed our understanding of the brain, and why the question of presence could complement this theoretical framework.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><u><a href=\"https:\/\/driss-boussaoud.rovexen.com\/en\/les-dimensions-de-la-presence\/\" target=\"_blank\" rel=\"noreferrer noopener\">Phenomenology of Presence:<\/a><\/u><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Why certain ordinary experiences \u2014 shared silence, feeling watched, soothing or threatening presence \u2014 can help us understand the role of presence in human experience.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><u><a href=\"https:\/\/driss-boussaoud.rovexen.com\/en\/la-presence-avant-la-relation\/\" target=\"_blank\" rel=\"noreferrer noopener\">Presence before the relationship<\/a><\/u><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">In an elevator, a waiting room or a train, the mere presence of another person is often enough to transform our experience.<\/p>\n\n\n\n<h3 class=\"wp-block-heading translation-block\">YouTube Channel \u2014 The Brain of Presence<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Videos, reflections and explorations around the neuroscience of presence, attachment, development and psychotherapy.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Driss Boussaoud, Le Cerveau de la Pr\u00e9sence<\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Pour me contacter, utiliser ce lien.<\/em><\/p>","protected":false},"excerpt":{"rendered":"<p>Les racines biologiques de la socialit\u00e9\u2026 La pr\u00e9sence des autres influence-t-elle le vivant depuis plus longtemps que le cerveau lui-m\u00eame [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":2071,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center 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