Our everyday lives are shaped by conscious experience. At times, this experience is pleasant, such as feeling sunlight on your skin, hearing birds sing, or simply enjoying a peaceful moment. At other times, it is painful, whether from a physical injury like hurting your knee on the stairs or from ongoing emotional struggles such as chronic pessimism. This raises a fundamental question: why did living beings evolve a form of perception that includes pleasure, pain, and even intense suffering?
Albert Newen and Carlos Montemayor describe consciousness as having three distinct forms, each serving a different role: 1. basic arousal, 2. general alertness, and 3. a reflexive (self-)consciousness. According to Newen, basic arousal was the first to emerge in evolutionary history. “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,” he explains. Pain plays a crucial role here. “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.”
How Attention and Learning Evolved
A later evolutionary development is general alertness. This form of consciousness allows an individual to focus on one important signal while filtering out others. For example, if someone is talking to you and you suddenly notice smoke, your attention shifts immediately to the smoke as you look for its source. As Carlos Montemayor explains, “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.”
Self Awareness and Social Life
Humans and some other animals go a step further by developing reflexive (self-)consciousness. In its more advanced form, this ability allows individuals to think about themselves, remember the past, and anticipate the future. It also makes it possible to build a mental image of oneself and use that image to guide decisions and plans. Newen notes, “Reflexive consciousness, in its simple forms, developed parallel to the two basic forms of consciousness. In such cases conscious experience focuses not on perceiving the environment, but rather on the conscious registration of aspects of oneself.” These aspects include bodily states, perceptions, sensations, thoughts, and actions.
A simple example of reflexive consciousness is recognizing oneself in a mirror. Human children usually develop this ability around 18 months of age. It has also been observed in certain animals, including chimpanzees, dolphins, and magpies. At its core, reflexive conscious experience supports social integration and coordination with others, helping individuals function within groups.
What Birds Perceive
Research by Gianmarco Maldarelli and Onur Güntürkün suggests that birds may also possess basic forms of conscious perception. Their work highlights three main areas where birds show strong similarities to mammals: sensory consciousness, underlying brain structures, and forms of self-consciousness.
Evidence of Sensory Experience in Birds
Studies of sensory consciousness show that birds do more than automatically react to stimuli. They appear to have subjective experiences. When pigeons are shown visually ambiguous images, they alternate between different interpretations, much like humans do. Research on crows provides further evidence. Certain nerve signals in their brains reflect what the animal perceives rather than the physical stimulus itself. When a crow sometimes consciously detects a stimulus and sometimes does not, specific nerve cells respond in line with that internal experience.
Bird Brains and Conscious Processing
Bird brains also contain structures that support conscious processing, even though their anatomy differs from that of mammals. Güntürkün explains, “The avian equivalent to the prefrontal cortex, the NCL, is immensely connected and allows the brain to integrate and flexibly process information.” He adds, “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.”
Signs of Self Perception in Birds
More recent experiments indicate that birds may also show forms of self-perception. While some corvid species pass the classic mirror test, other studies use alternative approaches that better reflect birds’ natural behaviors. These experiments reveal additional forms of self-consciousness in different species. Güntürkün notes, “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.”
Taken together, these findings suggest that consciousness did not emerge recently or exclusively in humans. Instead, it appears to be an ancient and widespread feature of evolution. Birds demonstrate that conscious processing can occur without a cerebral cortex and that very different brain structures can arrive at similar functional outcomes.
