Although scientific research about consciousness has enjoyed a boom in the past two decades, one central question remains unanswered: What is the function of consciousness? Why did it evolve at all? The answers to these questions are crucial to understanding why some species (such as our own) became conscious while others (such as oak trees) did not. Furthermore, observing the brains of birds shows that evolution can achieve similar functional solutions to realize consciousness despite different structures. The working groups led by Professors Albert Newen and Onur Güntürkün at Ruhr University Bochum, Germany, report their findings in a current special issue of the journal Philosophical Transactions of the Royal Society B from November 13, 2025.
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