Why do we have a consciousness?
Philosophy and psychology
Ruhr-University Bochum
Purposes of pleasure and pain?
Our conscious experience makes up our lives, often through positive pleasure: I feel the warm sun on my skin, I hear the singing of birds, I enjoy the moment. Yet we also often experience pain: I feel my knee hurt from falling on the stairs, I suffer from always being pessimistic. Why have we, as living creatures, even developed a perception that can involve positive experiences as well as pain and even unbearable suffering?
Albert Newen and Carlos Montemayor categorize three types of consciousness, each with different functions: 1. basic arousal, 2. general alertness, and 3. a reflexive (self-)consciousness. “Evolutionarily, basic arousal developed first, with the base function of putting the body in a state of ALARM in life-threatening situations so that the organism can stay alive,” explains Newen. “Pain is an extremely efficient means for perceiving damage to the body and to indicate the associated threat to its continued life. This often triggers a survival response, such as fleeing or freezing.”
A second step in evolution is the development of general alertness. This allows us to focus on one item in a simultaneous flow of different information. When we see smoke while someone is speaking to us, we can only focus on the smoke and search for its source. “This makes it possible to learn about new correlations: first the simple, causal correlation that smoke comes from fire and shows where a fire is located. But targeted alertness also lets us identify complex, scientific correlations,” says Carlos Montemayor.
Humans and some animals then develop a reflexive (self-)consciousness. In its complex form, it means that we are able to reflect on ourselves as well as our past and future. We can form an image of ourselves and incorporate it into our actions and plans. “Reflexive consciousness, in its simple forms, developed parallel to the two basic forms of consciousness,” explains Newen. “IN such cases conscious experience focuses not on perceiving the environment, but rather on the conscious registration of aspects of oneself.” This includes the state of one’s own body, as well as one’s perception, sensations, thoughts, and actions. To use one simple example, recognizing oneself in the mirror is a form of reflexive consciousness. Children develop this skill at 18 months, and some animals have been shown to do this as well, such as chimpanzees, dolphins, and magpies. Reflexive conscious experiences – as its core function – makes it possible for us to better integrate into society and coordinate with others.
Original publication
Albert Newen, Carlos Montemayor: Three Types of Phenomenal Consciousness and Their Functional Roles: Unfolding the ALARM Theory of Consciousness, in: Philosophical Transactions of the Royal Society B, DOI: 10.1098/rstb.2024.0314
What Birds Perceive
Gianmarco Maldarelli and Onur Güntürkün show in their article that birds may possess fundamental forms of conscious perception. The researchers highlight three central areas in which birds show remarkable parallels to conscious experience in mammals: sensory consciousness, neurobiological foundations, and accounts of self-consciousness.
Firstly, studies of sensory consciousness indicate that birds not only automatically process stimuli, but subjectively experience them. When pigeons are presented with ambiguous visual stimuli, they shift between various interpretations, similar to humans. Crows have also been shown to possess nerve signals that do not reflect the physical presence of a stimulus, but rather the animal’s subjective perception. When a crow sometimes consciously perceives a stimulus and does not at other times, certain nerve cells react precisely according to this internal experience.
Secondly, birds’ brains contain functional structures that meet the theoretical requirements of conscious processing, despite their different brain structure. “The avian equivalent to the prefrontal cortex, the NCL, is immensely connected and allows the brain to integrate and flexibly process information,” says Güntürkün. “The connectome of the avian forebrain, which presents the entirety of the flows of information between the regions of the brain, shares many similarities with mammals. Birds thus meet many criteria of established theories of consciousness, such as the Global Neuronal Workspace theory.”
Thirdly, more recent experiments show that birds may have different types of self-perception. Even though some species of corvids pass the traditional mirror test, other ecologically significant versions of the tests have shown further types of self-consciousness in other bird species. “Experiments indicate that pigeons and chickens differentiate between their reflection in a mirror and a real fellow member of their species, and react to these according to context. This is a sign of situational, basic self-consciousness,” says Güntürkün.
The findings suggest that consciousness is an older and more widespread evolutionary phenomenon than had previously been assumed. Birds demonstrate that conscious processing is also possible without a cerebral cortex and that different brain structures can achieve similar functional solutions.
Original publication
Gianmarco Maldarelli, Onur Güntürkün: Conscious Birds. in: Philosophical Transactions of the Royal Society B, DOI: 10.1098/rstb.2024.0308
Journal
Philosophical Transactions of the Royal Society B Biological Sciences
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
Three Types of Phenomenal Consciousness and Their Functional Roles: Unfolding the ALARM Theory of Consciousness
Article Publication Date
23-Nov-2025
What can psychedelics teach us about the sense of self?
Researchers used a psychedelic as a tool to advance understanding of brain activity for the human sense of self.
Society for Neuroscience
When people use a psychedelic called dimethyltryptamine (DMT), they experience a temporary loss of their sense of self. DMT interacts with a frequency of brain activity associated with self-referential processes (alpha waves), but it’s unclear how this activity relates to self-awareness. Christopher Timmerman, at University College London, and Marco Aqil, currently at the University of Miami, are among researchers who used DMT as a tool to explore the relationship between alpha waves and self-awareness.
As reported in their JNeurosci paper, the researchers discovered that DMT interacts with alpha waves in a way that is associated with stronger ratings of loss of the sense of self, sometimes termed ego death. These activity changes were related to what is termed “criticality.” Elaborates Timmerman, “The way the brain operates between chaos and order allows for normal brain function. Criticality refers to a brain state balanced between chaos and order that helps us predict things about the environment, the way we change or adapt to it, and our self-awareness.”
Furthermore, the researchers found that this shift away from criticality was a dampening or quieting of alpha waves. Describing what this might mean, says Aqil, “We rely on past narratives and future predictions to have a coherent sense of self. In a DMT experience, people do not have a stream of consciousness over a period of time—everything takes place in the present moment. This shift in criticality signatures in the alpha frequency [during a DMT experience likely reveals how] the time-extended component of the sense of self is weakened.”
Both Timmerman and Aqil emphasize their work supports the idea that psychedelics may be a powerful tool for unraveling the neurological basis of human consciousness.
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Please contact media@sfn.org for full-text PDF.
About JNeurosci
JNeurosci was launched in 1981 as a means to communicate the findings of the highest quality neuroscience research to the growing field. Today, the journal remains committed to publishing cutting-edge neuroscience that will have an immediate and lasting scientific impact, while responding to authors' changing publishing needs, representing breadth of the field and diversity in authorship.
About The Society for Neuroscience
The Society for Neuroscience is the world's largest organization of scientists and physicians devoted to understanding the brain and nervous system. The nonprofit organization, founded in 1969, now has nearly 35,000 members in more than 95 countries.
Journal
JNeurosci
Subject of Research
People
Article Title
DMT-Induced Shifts in Criticality Correlate with Self-Dissolution
Article Publication Date
24-Nov-2025
COI Statement
One author is a shareholder of Aspect Neuroprofiles BV, which develops physiology-informed prognostic measures for neurodevelopmental disorders. All other authors declare no competing financial interests
A virtual clinical trial of psychedelics to treat patients with disorders of consciousness
International team ran a “virtual clinical trial” of psychedelics on computer models of patients’ brains. These drugs could, in theory, push brain activity towards more flexible, conscious-like dynamics in some patients with disorders of consciousness
University of Liège
image:
Cover image of issue 11 of Advanced Science.
view moreCredit: ULiège/N.Alnagger
Researchers from the University of Liège and international collaborators developed a “virtual clinical trial” exploring a unique pharmacological treatment in patients who do not fully regain consciousness after a coma. The proposed treatment involves employing psychedelic drugs, such as psilocybin and lysergic acid diethylamide (LSD) that have intense, consciousness-altering effects in healthy volunteers. Those remarkable experiences are thought to be linked with increased dynamical complexity of brain activity. In patients with disorders of consciousness (DoC), dynamic brain function is importantly reduced, potentially resulting in decreased consciousness. Therefore, the proposed treatment effects hinge upon the premise that a short-term increase in the complexity of brain activity in patients could result in improvements in the conscious state of these patients.
Performing clinical trials with psychedelic drugs is burdened with legal obstacles and necessitates careful planning and ethical considerations. However, in the study by Alnagger et al., published in Advanced Science, the authors innovatively utilised personalised computational models of patients’ brains, built from individual MRI scans (functional MRI and diffusion-weighted imaging). After constructing a computational model of each patient’s brain, they simulated the effects of LSD and psilocybin as would be performed in a clinical trial, yet virtually. The researchers demonstrated that these substances could shift brain activity in patiens with DoC towards healthier, more flexible and complex dynamics.
To study the dynamics of simulated brain activity, the authors observed how an artificial perturbation was integrated into the brain’s activity in time and magnitude. “In order to understand any dynamical system, in this case the brain, it’s often useful to perturb it” said Naji Alnagger, first author, PhD candidate of the Coma Science Group. “Imagine if you want to understand how viscous a liquid is, in other words, its dynamics, you could poke it. By observing how it reacts to the perturbation, how long it takes to return to baseline and the degree it is disturbed could reveal a lot of information as to the viscosity. The same is true here, observing how the model reacts after introducing an artificial perturbation can tell us about the nature of dynamics of the brain activity.”
The researchers first validated this method of simulated perturbations by showing that the response to perturbation was lower in states of lower consciousness such as DoC patients and healthy participants under anaesthesia compared to normal waking consciousness. They then showed that under psychedelics, perturbation induces an even greater response than in healthy individuals without the drug.
The researchers found that simulating LSD and psilocybin on patients with DoC boosted their responses to perturbations. The effect was greater in patients with some minimal signs of non-reflex behaviour (minimally conscious state) compared to patients with no detectable signs of clinical awareness (unresponsive wakefulness syndrome). Stratifying by these two diagnostic groups, the researchers also found that the simulated treatment effect was more correlated with the strength of the brain structural connectivity in the UWS patients, and with the strength of the brain functional connectivity in the MCS patients. “What was particularly noteworthy was that the MCS and UWS patients have the same level of structural connectivity strength, what differed was the efficiency of the existing connectivity, therefore it seems that, not only connectivity strength but efficient organisation was critical in sustaining the psychedelic related shifts in dynamics” said Dr. Jitka Annen, senior author and researcher at the University of Ghent.
“The results of the study suggest that if this treatment was to be carried out in real clinical settings, the type of patients who would most likely benefit would be an MCS patient with a strongly connected functional connectivity. This provides a starting point to target potential future clinical trials.” said Dr. Olivia Gosseries, director of the Coma Science Group.
Computational models offer a way to test treatments in silico, identify good potential candidates and investigate the mechanisms of a particular treatment. “This is an important proof of concept,” said Naji Alnagger. “While much more work is needed before any form of clinical application, this study shows how personalised computational modelling could one-day form a valuable part of pre-clinical work and personalised medicine.”
*The study was performed in collaboration with the University hospital of Liège (CHU de Liège), Imperial College London, Maastricht University, Sorbonne University, Universitat Pompeu Fabra, and other international partners.
Journal
Advanced Science
Article Title
A Virtual Clinical Trial of Psychedelics to Treat Patients With Disorders of Consciousness
Article Publication Date
21-Nov-2025
