A Dutch study found that by 30 weeks of age a fetus can remember a sound for 10 minutes. By week 34, a fetus may be able to remember.
During rapid-eye-movement sleep, when we dream, the brain is thought to be processing stored memory. The memory of a newborn infant is dominated by its fetal experience, and the infant is likely to dream about its life in the womb. Research with lucid (or conscious) dreaming has shown that dream images are supported by the corresponding body actions, using those muscles which remain active during rapid-eye-movement sleep.
We suggest that sudden infant death syndrome or cot death may be a result of an infant dreaming about its life (or memory) as a fetus. In the course of that dream, since a fetus does not breathe (in the usual sense) the infant may cease to breathe and may die. This simple hypothesis is consistent with all of the known facts about sudden infant death syndrome (pathological and epidemiological), such as the age at death curve (the observed exponential decay and possibly the peak at 2-3 months), the higher risk with the prone sleeping position (but not excluding the supine position), and the observed climatic variation (seasonal and regional) in the incidence of sudden infant death syndrome.
Many of these well-established facts have no other known explanation and other theories can generally only account for a few of the known facts about sudden infant death syndrome. Our hypothesis is also supported by recent findings that, as a group, sudden infant death syndrome infants have a higher proportion of rapid-eye-movement sleep, and also that they have an average higher heart rate (corresponding to possible fetal dreams) but only during rapid-eye-movement sleep.
The memory of a newborn infant is dominated by its fetal experience, and the infant is likely to dream about its life in the womb. Research with lucid.
As a fetus grows inside a mother’s belly, it can hear sounds from the outside well enough to retain memories of them after birth, according to research at the University of Washington in Seattle.
Nursery rhyme experiment reveals that by their 34th week in utero, fetuses remembers.
If you’ve ever been pregnant, did you have a saying you’d repeat to yourself–something about taking things one day at a time, or maybe even wishing that men could know what it’s like to carry a child? Or did you have a favorite song you’d listen to obsessively? Well, if you said or heard something like that over and over again during pregnancy, your newborn may remember it too.
A study funded by the National Science Foundation’s Social Behavioral and Economic Sciences Directorate suggests babies begin to acquire knowledge in the womb earlier than previously thought.
Research led by Charlene Krueger, an associate professor at the University of Florida’s (UF) College of Nursing, and published in the journal Infant Behavior and Development, provides evidence that what fetuses hear by their 34th week in utero can inspire learning. That’s three weeks earlier than the evidence of learning detected by previous research.
By the 38th week of pregnancy, memory is evident; births normally occur around 40 weeks.
Krueger conducts research on early developmental exposure to sound, specifically maternal voice. She and co-investigator Cynthia Garvan, the UF’s statistics director in the Office of Educational Research, asked 32 women to repeat aloud the same 15-second nursery rhyme twice a day for six weeks from their 28th week of pregnancy through their 34th week.
After the 34th week, the mothers stopped reciting the nursery rhyme. All along, they visited a lab at 28, 32, 33 and 34 weeks’ gestation to determine whether the unborn babies had familiarized themselves with the nursery rhyme. They also came in for testing at 36 and 38 weeks.
Lab testing involved measuring the fetuses’ heart rates while the unborn babies listened to a recorded female voice repeat the same nursery rhyme that was spoken at home by the mothers.
If the heart rate accelerated, the researchers surmised the fetuses hadn’t totally grasped the new sounds. If the heart rate decelerated, it meant the fetuses found the nursery rhyme familiar.
Krueger and Garvan found that by the 34th week, the heart rates of the fetuses began to decline while listening to the recording. By 38 weeks, four weeks after their mothers stopped repeating the rhyme, testing found statistically evident heart rate deceleration, meaning the fetuses remembered the rhyme.
Meanwhile, a control group of fetuses heard a different rhyme, also spoken by a stranger. Since a mother’s voice is the main source of sensory stimulation for an unborn baby, the researchers wanted to determine if the fetuses simply were responding to their mothers’ voices rather than to a familiar pattern of speech. When this group listened to a recording of a new nursery rhyme, their heart rates slightly accelerated.
Krueger and Garvan concluded that the fetuses in the experimental group were responding to the nursery rhyme; that they begin to show evidence of learning by 34 weeks gestational age; and that they are capable of remembering what they hear inside the womb.
The study’s goal was to increase basic knowledge of not only when, but ultimately how, humans learn and remember. This is important to a baby’s experience in neonatal intensive care units, as new technologies give preterm infants a greater chance of survival and alter patterns of stimulation for developing fetuses in and out of the womb.
Further study is needed to more fully understand how ongoing experience, in the context of ongoing development in the last trimester of pregnancy, affects learning and memory.
Credit: National Science Foundation