When does our inner world begin? With the first breath, the first touch, a familiar voice? Research on the infant brain is gradually bringing science closer to this question. Even by birth, certain organizational features are found in the brain that in adults are associated with conscious perception. And individual reactions to sounds appear in the final weeks of pregnancy. The hardest thing is to understand when experience arises behind information processing: what it is like to hear, to feel, to be.
In a review published in Neuron in 2024, the philosopher and consciousness researcher Claudia Passos-Ferreira of New York University compared neurophysiological and behavioral data. In her assessment, the body of results supports the hypothesis that newborns already possess conscious experience. What is meant is the capacity to subjectively feel something; reflections about oneself and the ability to describe one's feelings belong to other, more complex capacities.
One of the most curious experiments begins with repeating sounds. In a 2021 study, scientists recorded magnetic signals from the brains of 56 fetuses at gestational ages from 25 to 40 weeks. They were presented with sequences of tones in which the familiar pattern was sometimes violated. After 35 weeks, the researchers detected more consistent signs of recognizing changes in the structure of repeating sequences. The authors interpreted this as possible evidence of conscious processing. At the same time, they emphasized separately: from such data it is impossible to establish the exact week when consciousness arises.
A subtlety matters here. The brain is capable of automatically noticing a single unusual sound. A more complex task is to catch a violation of a rule that is formed from several sound sequences. It is precisely reactions to such violations that attract consciousness researchers. However, an alternative explanation remains: an immature brain may perceive an entire sequence as a single sound, and then the response reflects simpler recognition of novelty. Therefore, the results of intrauterine studies so far allow for different interpretations.
Another path to an answer is studying how brain regions communicate with one another. In the work of Huiqing Hu, Rodrigo Quian Quiroga, and Lorina Naci, published in Brain Communications in 2022, analyzed functional MRI of 282 full-term infants and two groups of preterm infants — with 73 examinations in each.
By full-term gestational age, the researchers could already distinguish the attention, executive control, and default mode networks. In adults, these systems participate in allocating attention, organizing information processing, and internally directed processes. In infants, their organization differed from that of adults, and premature birth was associated with changes in network organization. When examined at earlier gestational ages, only the attention network stood out clearly among these three systems. This is evidence of the maturation of the possible infrastructure of consciousness; such scanning leaves the content of the child's experiences an open question.
How can these disparate signs be assembled into a convincing picture? Joel Frohlich and Tim Bayne propose a "cluster" approach. Its logic is simple: confidence increases when several independent indicators converge in the same age period. Among them are the interaction of brain networks, reactions to the violation of complex regularities, and the integration of information from different sense organs.
In a mini-review published online in 2024 and included in the issue Acta Paediatrica for 2025, the authors conclude that consciousness is probably present by five months, and possibly considerably earlier. Data on brain networks make brief periods of conscious experience plausible already at birth or shortly thereafter. The possibility of experiences before birth remains more disputed.
This is the main paradox: the capacity to experience the world may appear long before the capacity to report what has been experienced. For the researcher, speech serves as convenient evidence of consciousness. Infancy requires learning to read other evidence — and taking into account that similar signals in an adult and a child may arise through different mechanisms.
This discussion has a thoroughly practical side. In neonatal care, the prevention and relief of pain are already among the mandatory components of care. Current recommendations provide for pain assessment, appropriate analgesia, and the participation of parents in supporting the child. These measures are needed now, while researchers continue to clarify the nature of early subjective experience.
For now, science leaves the date of the beginning of our inner life open. But it does help to formulate the question itself more precisely: what sensations are accessible to a child at each stage of development, and how can we recognize them? For parents and specialists, there is a humanly important perspective here — to pay closer attention to the being whose experience is still expressed through movement, gaze, crying, and changes in state. Before the first word, a space of care is already taking shape between people.
