At Psyche, University of Tübingen neuroscientist Joel Frohlich asks, “When does the first spark of human consciousness ignite?” in a human being?

It’s a tough questions for several reasons: First, human consciousness is very hard to define for the purposes of this kind of research. We all know that we are conscious but the fuzziness begins when we try to step outside of our consciousness and talk about it.

That amounts to trying to talk about subjectivity objectively. Not impossible, but not for beginners either.

Second, as neuroscientist Christof Koch has noted, babies, born and unborn, spend most of their time asleep. But we cannot therefore say that they are not conscious. Sleep is not equivalent to lack of thought; it is withdrawal from our usual level of sensory awareness.

Frohlich offers some thoughts about how to assess the question, based on a recent scholarly review, of which he is one of the authors.

Does consciousness start after birth?

Research has not shed much light on when consciousness begins. Frohlich tells us that numerous studies of electrical brain activity suggest that neural complexity increases in the early postnatal period but he and colleagues have published evidence that it decreases. Of course, not all complexity is functional; perhaps some of it is just a mess that gradually gets sorted out. He concludes,

There are other reasons why sceptics doubt that newborns are conscious. Often, these involve the implausibility of selfhood during infancy: how could a new baby have any concept of ‘I’? But this is a confusion of terms. Having an experience doesn’t require having a self. As adults, we often lose ourselves in states of flow, or deep immersion in music, exercise, work or sex. Similar states, absent a self, can occur during meditation. To claim that these are non-experiences, lacking any consciousness, is nonsense. Consciousness has no need for a self. “October 29, 2024”

These are deep and wide issues. We mainly want to know things like “Do newborns suffer from needle sticks?” It might be wise to conclude that infants who scream in apparent pain have enough of a self to actually experience it.

Does it start at birth?

Frohlich offers the case that birth is the event that sparks the consciousness which is needed to make sense of the new post-birth environment:

Assuming that consciousness serves a practical purpose, and is not merely a side-effect of the brain’s information-processing, there is a fairly strong case for consciousness emerging at birth. A newborn has left the safety of the womb, and the body’s new need for autonomy may necessitate awareness and subjectivity. “October 29, 2024”

But why, exactly, would consciousness simply “emerge” at birth? His further description of what consciousness does at that point suggests that it is already latent:

The ability of newborns to form expectations about the world might be evidence for consciousness at birth. Neuroscientists such as Anil Seth favour a view of consciousness known as predictive coding. According to this view, consciousness does not arise from raw sensory input to our brains, but rather from our inferences about the outside world. These inferences are based on both the new information reaching our sense organs and our prior models of how things ought to be. “October 29, 2024”

If we have “prior models of how things ought to be” at birth, aren’t we already conscious?

Does it start before birth?

Frohlich begins by prudently denying that anything he has to say affects abortion laws because most countries restrict late-term abortion anyway. (Canada and North Korea are exceptions.) That said,

Could a fetus be conscious of anything before the third trimester, unplugged from the world and even its own body? It is difficult to imagine what it would be like to exist as a new mind that does not, and never did, see, hear, touch or taste. Before the third trimester, the fetus is likely in a state akin to deep sleep. Recent research found that infants given spinal anaesthesia, which blocks most sensations from the body, show electrical brain activity that resembles sleep. The fetal brain, being even less mature, is even less likely than that of an infant to sustain consciousness without sensory input. Furthermore, the womb’s bath of sedating chemicals inhibits wakefulness even after sensory signals reach the cortex in the third trimester.

If consciousness does emerge before 24 weeks, it is not likely consciousness as we generally know it, but rather more likely the contentless consciousness described by philosophers such as Thomas Metzinger: with no incoming sensations to divide up the passage of time or to delineate space, all is timeless, spaceless and empty. “October 29, 2024”

That’s somewhat mystical, of course, and Frohlich is quick to admit that the whole area is highly speculative.

Overall, based on available evidence, he thinks consciousness emerges gradually, beginning near birth. But again, we run into the problem of determining what consciousness even is.

Here’s a question: Is there a continuity between a human being’s consciousness today and that same person’s consciousness at say, six months before birth? If there is no consciousness at three months’ gestation, what is consciousness and how does it arise in the human being? Can there really be a biological human being without consciousness?

These are the kinds of questions that make consciousness the “Hard Problem” in philosophy, one that neuroscience cannot easily answer.

You may also wish to read: What is the human mind like before birth? Researchers stress that the unborn child’s brain is in a rapid, ongoing, and little understood state of development. While the unborn child sleeps most of the time, during waking hours, he or she practices various skills that will be needed after birth.