One complication ensues. When people awaken during REM sleep, they often report vivid dreams with extensive narratives. Although consciousness during dreams is not the same as during wakefulness—most noticeably insight and self-reflection are absent—dreams are consciously experienced and felt. So does the fetus dream when in REM sleep? This is
not known. But what would it dream of?
After birth, dream content is informed by recent and more remote memories. Longitudinal studies of dreaming in children by retired American psychologist David Foulkes suggest that dreaming is a gradual cognitive development that is tightly linked to the capacity to imagine things visually and to visuospatial skills. Thus, preschoolers’ dreams are often static and plain, with no characters that move or act, hardly any feelings and no memories. What would dreaming be like for an organism that spends its time suspended in a sort of isolation tank, with no memories, and no way to imagine anything at all? I wager that the fetus experiences nothing in utero; that it feels the way we do when we are in a deep, dreamless sleep.
The dramatic events attending delivery by natural (vaginal) means cause the brain to abruptly wake up, however. The fetus is forced from its paradisic existence in the protected, aqueous and warm womb into a hostile, aerial and cold world that assaults its senses with utterly foreign sounds, smells and sights, a highly stressful event.
As Hugo Lagercrantz, a pediatrician at the Karolinska Institute in Stockholm, discovered two decades ago, a massive surge of norepinephrine—more powerful than during any skydive or exposed climb the fetus may undertake in its adult life—as well as the release from anesthesia and sedation that occurs when the fetus disconnects from the maternal placenta, arouses the baby so that it can deal with its new circumstances. It draws its first breath, wakes up and begins to experience life.
Note: This article was originally printed with the title, "When Does Consciousness Arise?"