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Evolutionary Significance of Altered States of Consciousness

On the Necessity of Nervous System Flexibility and Related Questions

 · 19 min read

Introduction

The human brain’s ability to enter altered states of consciousness is one of the most striking manifestations of the nervous system’s flexibility. Throughout human history, these states have appeared in many different forms and cultural contexts—during religious rituals, meditation, dance, singing, childbirth, intense physical exertion, deep interpersonal closeness, in crisis situations, or during specific forms of physical experience. Although these states can be subjectively very different, their common feature is a temporary change in the way the nervous system organizes perception, attention, emotions, bodily signals, and a person’s relationship to their own self.

From the perspective of a common, intuitive understanding of consciousness, altered states may seem extraordinary or unusual. However, contemporary neurobiology offers a different view. The human brain is not a hard-wired system with a single optimal mode of functioning. On the contrary, one of its most significant characteristics is the ability to change its functional organization according to current biological, environmental, and social conditions.

From this perspective, the main question is not why the human brain sometimes creates altered states of consciousness, but why evolutionary processes led to the emergence of a nervous system that allows such extensive changes in the first place. Why does the organism have mechanisms capable of altering the perception of time, space, pain, bodily sensations, emotions, or the subjective sense of identity?

The answer is tied to the very nature of biological adaptation. Evolution does not create organisms as static machines optimized for only one specific situation. Living systems must function in environments that are constantly changing, contain uncertainty, and often require different survival strategies. Therefore, an organism doesn’t just need the ability to react effectively. It also needs the ability to change how it reacts.

Evolutionary Premise: This flexibility does not mean that every specific altered state of consciousness represents a distinct, purposefully evolved adaptation. While we do not know with certainty the exact evolutionary purpose of many of these states, we estimate that many biological abilities arise rather as part of broader systemic properties and are subsequently utilized in various situations. The ability to enter altered states of consciousness did not necessarily evolve so that the organism could achieve specific types of experiences, but likely because the nervous system gained an extraordinary ability to reorganize itself based on what appears most appropriate in a given moment.

The Evolution of the Nervous System as the Evolution of Flexibility

The brain is among the most energy-demanding organs in the human body. Even though it represents only a relatively small portion of body weight, it consumes a significant amount of metabolic resources. From an evolutionary perspective, it is therefore unlikely that the extensive regulatory mechanisms of the nervous system would persist without profound significance for the organism’s functioning. Current findings suggest that the brain’s ability to adapt its own functional state is not merely a random byproduct of neuronal activity. It likely reflects a fundamental property of the nervous system that enables the adaptive regulation of behavior and physiological processes. It is assumed to stem from the core operating principle of the nervous system—the need to continuously adjust behavior, attention, emotions, and bodily regulation to current conditions.

This principle is fundamentally different from the idea of the brain as a device whose sole task is to accurately and passively record the surrounding reality. Contemporary neuroscientific models view the brain as an active regulatory system that constantly evaluates the state of the organism, the environment, and social situations. Biologically, it is not optimal to exist perpetually in the same setting, because every situation requires a different way of processing information. An organism facing an immediate threat needs quick orientation, high sensitivity to danger, and the capacity for instant physical reaction. Conversely, an organism in a safe environment can allocate its resources entirely differently—for learning, social connection, regeneration, creativity, or long-term planning.

In this evaluation process, the brain doesn’t just work with the question “What is happening right now?” but simultaneously addresses:

This principle is the foundation of the predictive coding theory of the nervous system. According to this model, the brain constantly generates models of future events and compares them with newly incoming information. If the expectations and reality match, the organism can function efficiently and with lower energy demands. However, if a discrepancy arises, a so-called prediction error occurs.

A prediction error is not a sign that the brain simply made a mistake. It is considered one of the most crucial mechanisms for learning and adaptation. It informs the nervous system that its current model of the situation is not accurate enough and needs to be adjusted. An organism capable of using prediction errors to update its internal models gains the ability to react more quickly to new conditions. It is precisely this constant updating that is the probable reason why the human brain is not rigidly confined to a single mode of functioning.

The nervous system likely operates as a dynamic network of various regulatory modes. These modes are not hierarchically organized such that one is “correct” and the others are inferior. Each represents an adaptive configuration suited for specific conditions.

From this viewpoint, altered states of consciousness can be understood as situations where there is a temporary shift in the priorities of individual systems. Certain forms of information processing are amplified, while others lose prominence. Attention may shift from the external environment to internal bodily processes, analytical control may give way to direct experience, and social or emotional information may gain more weight than standard cognitive evaluation.

Therefore, this process is not related to a failure of regulation but represents the very manifestation of its capability and flexibility.

Altered States of Consciousness as an Adaptive Mechanism

If we accept the premise that the fundamental evolutionary advantage of the human brain is the capacity for adaptive change, then altered states of consciousness no longer appear as exceptions. Subjective experience arises from the integration of many parallel processes, including sensory perception, bodily regulation, emotional appraisal, memory, attention, motivation, and the ability to construct a self-model. The ordinary state of consciousness represents just one specific configuration of these systems.

Contemporary neuroscience is therefore increasingly abandoning the idea of consciousness as a static state, leaning towards the hypothesis that it is a dynamic process emerging from the coordinated activity of widespread neural networks. Thus, a change in consciousness does not necessarily mean a disruption of brain function, but rather a shift in how these individual systems collaborate.

One of the key principles of this reorganization is the reallocation of attention. Attention is a limited biological resource. Attentional selectivity is crucial for survival: in an environment full of information, the organism must constantly decide which stimuli to devote energy to and which to ignore. A hunter tracking an animal, a parent responding to a child’s signals, an athlete during performance, or a person in a crisis situation all utilize a similar principle: the nervous system temporarily highlights a specific part of reality and suppresses information that is not a priority at that given moment.

Altered states of consciousness often involve precisely this kind of dramatic shift in the distribution of attention. Broad environmental monitoring can be replaced by an intense focus on internal bodily sensations, emotional states, or the activity process itself.

Note: The following overview should be read as a set of theoretical hypotheses derived primarily from research on other well-documented states (meditation, pain, social bonding, sleep) and applied to a broader spectrum of phenomena—for many of these (especially subspace, hypnotic trance, or crowd trance), direct neuroimaging data is practically nonexistent:

| Phenomenon | Neurobiological Assumption | Subjective Manifestation | | Flow State | Optimization of the ratio between automated skills, bodily feedback, and transient hypofrontality (suppression of disruptive cognitive control). | Altered perception of time, reduced sense of conscious effort, absolute focus on the present process. | | Hyperfocus (ADHD/Autism) | Dysregulation of the dopamine system leading to a limited ability to smoothly shift attention; under high stimulation, the brain allocates a large portion of resources to a single point. | Loss of track of time, ignoring bodily needs (hunger, fatigue), significant disconnection from surroundings. | | Meditative States | The brain’s ability to change how it assigns meaning to internal stimuli; dampening of reactions to distractors and decreased activity in the Default Mode Network (DMN) noted in some studies. | Thoughts and bodily signals are observed without the need to immediately react; feeling of internal distance and calm. | | Active Imagination / Deep Visualization | Conscious modulation of attention aimed at strengthening the internal imagery apparatus while partially inhibiting reactions to external sensory stimuli. | Internal scenery gains vividness and autonomy; the external world fades into the background without loss of conscious control. | | Subspace / Riggery / BDSM Trance | Hypothesis derived from research on pain, social bonding, and meditation: modulation of the autonomic nervous system toward vagal dominance, possible involvement of endogenous opioids, oxytocin, and dopamine, and dampening of part of the prefrontal cortex. | Deep sense of safety and surrender, often significant analgesia (pain suppression), narrowing of perception to present touch/pressure, feeling of slowed time. | | Deep Co-regulation / Empathy | Synchronization of the autonomic nervous systems of two people (via the ventral vagus, mirror neurons, micro-expressions, and vocal tone). | Calming of the internal monologue, high sense of safety, feeling of deep mutual understanding without the need for words. | | ASMR / Touch Absorption | Activation of unmyelinated C-tactile fibers responding to gentle touch or specific sounds; assumed role of oxytocin and decreased heart rate. | Intense pleasant tingling in the body, dampening of the internal monologue, transition into a state of passive, deep lightness. | | Intense Pain Threshold (Stress-induced analgesia) | Release of endogenous opioids and endocannabinoids in response to stress; dampening of nociceptive signals at the level of the spinal cord and thalamus. | A point of breakthrough relief: pain turns into a dull, distant pressure or significantly weakens; internal calm emerges and attention narrows to the breath. | | Extreme Physical Exertion (Runner’s High) | Accumulation of endocannabinoids and endorphins linked to selective inhibition of higher cognitive centers in favor of basic bodily regulation and motor skills. | Silencing of the “inner critic,” simplification of perception to the rhythm of breath and step, feeling of lightness and an increased threshold of tolerance for discomfort. | | Extreme Thermal Shock (Sauna / Cold Exposure) | Strong sympathetic activation followed by a transition into parasympathetic dominance after the stimulus ends (so-called vagal rebound). | Narrowing of attention solely to physical survival/breathing, followed by significant physical and mental calming. | | Hypnotic Trance | Increased functional connectivity between the executive attention network and the insula (bodily sensations) alongside a weakening of ordinary self-reflection. | Heightened susceptibility to suggestions, ability to suppress pain perception (hypnoanalgesia), or partially filter out ambient noise. | | Sensory Deprivation (Floatation Tanks) | A significant lack of external stimuli leads the brain to rely more on internal projections and spontaneous cortical activity. | Emergence of vivid internal imagery, hallucinations in some people, deep physical relaxation, and a weakening of the sense of one’s own physical boundaries. | | State of Awe | Sudden failure of existing mental schemas when confronted with an unusual/immense object; assumed dampening of the DMN and response in the amygdala. | Feeling of a “small self” (weakening of self-importance), shift of attention from internal monologue to the external object, often accompanied by chills down the spine. | | Deep Absorption in Art | High degree of engagement of the Salience Network alongside dampening of planning and motor areas. | Full immersion in the artwork, temporary weakening of the perception of one’s own body and surrounding space, intense emotional resonance. | | Rhythmic and Dance-Induced Trance | Entrainment (synchronization) of brain waves with an external rhythm (drumming, bass frequencies), supported by potential mild hyperventilation and fatigue. | Feeling of merging with the collective or the music, automated movement without conscious effort, weakening of analytical thinking. | | Collective Euphoria / Crowd Trance | According to social neuroscience hypotheses: mirror neurons and shared emotional signals within a group; possible diffusion of personal responsibility by shifting attention to the group. | Feeling of merging with the crowd (concert, match, ritual), sense of shared power, weakening of individual identity and self-control. | | Lucid Dreaming | Unusual hybrid activation of the prefrontal cortex (self-awareness) during the REM phase of sleep. | Awareness of the fact that one is dreaming, with the ability to consciously control the dream’s plot and direct attention within the dream world. | | Sleep Deprivation | Gradual collapse of sustained attention and the emergence of microsleeps (local sleep in certain parts of the cortex). | Episodic lapses in reacting to surroundings, getting mentally “stuck”, tunnel vision, and in prolonged deprivation, an increase in illusions or delusions. | | Dissociative States (Trauma / Overload) | Disrupted integration of perceptual and cognitive functions; weakened modulation between the insula, amygdala, and prefrontal cortex. | Feeling as if observing oneself from the outside (depersonalization) or that the surrounding world isn’t real (derealization); emotions feel disconnected. | | Fight or Flight (Survival Mode) | Hyperactivation of the amygdala, release of adrenaline and cortisol; temporary restriction of higher cognitive centers’ activity. | Tunnel vision, decreased sensitivity to irrelevant sounds, accelerated processing of key visual stimuli, feeling of slowed time. | | Psychedelic Experience | Decreased activity in the Default Mode Network (DMN) and increased connectivity of otherwise less-connected brain areas (via 5-HT2A receptors). | Weakening of a rigid sense of self, synesthesia (e.g., perceiving sounds as colors), blurring of boundaries between “self” and the surrounding world, alteration in the perceived meaning of things. | | Dissociative Anesthetics (Ketamine, etc.) | Antagonism of NMDA receptors, which disrupts the flow of signals between the cortex and lower structures (thalamus). | Feeling of the mind detaching from the body, “floating” in a void, disrupted perception of physical space and one’s own identity. | | Delirious States | Significant imbalance of neurotransmitters (especially acetylcholine and dopamine) leading to the disruption of network integration. | Difficulty maintaining a train of thought, difficulty distinguishing internal hallucinations from external reality, extreme volatility of attention. |

From an evolutionary perspective, it is precisely this ability to shift the balance between cognitive control and openness to experience that is significant. In an environment where it is necessary to quickly analyze risks and plan for the future, a high degree of control is advantageous. However, in an environment of safety, we estimate it may be more adaptive to allow for greater sensitivity to bodily signals, emotions, and social information.

Social Regulation, Safety, and the Importance of Relational States

The human brain exhibits profoundly relational characteristics. A significant part of its development occurred within social groups, where an individual’s survival depended not merely on reacting independently to physical stimuli, but primarily on the ability to form stable bonds, cooperate, and mutually regulate internal states.

Humans have developed an exceptionally strong ability to use the presence of another individual as a source of biological regulation. This mechanism is crucial from birth. An infant’s nervous system cannot independently stabilize its processes (temperature, stress responses, emotional tension); it is soothed by responding to a caregiver’s social signals—tone of voice, touch, facial expressions, and body heat. These pieces of information seemingly represent direct biological signals of environmental safety for the developing brain.

In adulthood, this mechanism does not disappear; it merely becomes more complex. We refer to this process as social or relational co-regulation. It is not that one person directly controls another’s nervous system; it is more accurate to estimate that it is a continuous exchange of biological information, where one person’s nervous system provides signals to the other, by which they can adjust their own state. For a species whose survival relies on cooperation, the ability to quickly build trust and reduce tension within a group is a massive evolutionary advantage.

Here lies the fundamental difference between the intensity of a physical experience and its biological interpretation. The nervous system doesn’t merely react to the mechanical force of a stimulus, but constantly evaluates its meaning in a broader context. This principle is clearly evident in the example of pain:

The brain doesn’t just ask: “How strong is this signal from the receptors?” It simultaneously asks: “What does this signal mean in this context, and how should I react to it?”

The nervous system constructs the complex experience of pain through a combination of sensory information, expectations, emotional state, and current context. This is why an athlete finishing a grueling performance, a mother during childbirth, or a person undergoing a consciously chosen intensive process perceives bodily signals completely differently than someone experiencing a sudden, unexpected injury.

Thanks to this interpretive ability, a person can undergo demanding physical experiences without every strong signal automatically triggering a defensive, stress response. If the organism evaluates the environment and relationship as safe, it can release resources that it would otherwise dedicate to defense and control. Bodily signals can be integrated without being appraised as a threat, which, according to our current estimates, opens the door for the emergence of profound altered states of consciousness.

Partner Intimacy as a Natural Context for Altered States

Partner intimacy represents one of the most prominent contexts in which the mechanisms of social regulation, bodily experience, and the altered settings of the nervous system intertwine. In a safe relational environment, a natural shift in priorities occurs: attention moves away from monitoring external risks toward a more intense perception of the body, emotions, and nonverbal communication.

While we intellectually understand that a high level of cognitive control is essential in everyday functioning (it allows us to plan, make decisions, and protect our boundaries), in a safe intimate context, it appears adaptive to temporarily lower this control. This state cannot be understood as passivity or a loss of autonomy; conversely, we assume it requires highly precise, unconscious regulation. The nervous system must constantly verify whether the partner remains trustworthy, whether boundaries are respected, and whether the environment is safe. Openness to intense experience is likely underpinned to a large extent by this ongoing evaluation of safety.

From a neurobiological standpoint, intimacy connects several evolutionarily older systems: social bonding, the reward system, stress regulation, and learning. Intense experiences in this context gain tremendous significance because they integrate multiple layers of processing simultaneously—bodily, emotional, social, and cognitive.

We can only surmise and estimate exactly how the nervous system stores these experiences, but current theory suggests it uses them to update its models of the world. If a person repeatedly experiences that openness, vulnerability, or intense physical sensations can safely unfold in a respectful environment, internal predictive models are gradually updated. There are also likely changes in synaptic plasticity that can manifest as a long-term shift in how similar situations are processed. The organism doesn’t just learn through rational thinking, but through the lived experience of the whole body.

Altered States of Consciousness, Neuroplasticity, and Learning

From a survival perspective, an organism would derive no benefit from merely feeling experiences intensely if it couldn’t change its future behavior based on them. Therefore, a significant property of the nervous system is neuroplasticity—the brain’s ability to change its own structure and functional organization based on experience.

However, the brain does not learn from all situations equally. If it permanently stored every ordinary stimulus, it would be overwhelmed. A more evolutionarily advantageous strategy is selective learning. Situations associated with a high degree of meaning, intensity, or surprise trigger mechanisms that likely increase the probability of their long-term storage in the neural network.

Here again, predictive processing and prediction error come into play. If we experience a situation that fundamentally disrupts our prior expectations, a significant prediction error occurs. We assume the nervous system flags it as potentially important and grants it increased plasticity to adjust internal models of reality for the future.

Crucially, context is key again—not in the sense that an organism in danger doesn’t learn, but in terms of the type of learning the given context promotes:

For example, if a person has long expected that vulnerability or loss of control automatically means danger, and in a new context repeatedly experiences that deep surrender and intense bodily sensations occur safely and predictably, this expectation can gradually change. This is not a simple “overwriting” or erasing of the old prediction—the original learned response may continue to exist alongside the newly forming expectation. Which one manifests in a given situation depends on context, stress levels, and other circumstances. It is therefore more accurate to speak of the emergence of a new, competing expectation or a reduction in the probability of the old response, rather than its complete overwriting.

Altered states of consciousness are circumstances where these processes can be activated particularly strongly. Due to altered attention and high emotional relevance, the brain processes information with extraordinary sensitivity, which can—under favorable conditions—enable a profound reorganization of the organism’s internal models.