Prenatal Learning

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Prenatal Learning
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Basic Issues

• How can we tell that the fetus can learn?
• Experimental Methodology
• What type of information might the fetus learn?
• How specific is that learning?

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How do we tell?

• Need to provide unique experience to infant in
  utero
• Test to see if fetus responds to unique
  experience
• Test to see if postnatal infant retains the
  information exposed to in utero

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Novelty-Preference

• Preset number of Familiarization Trials
• Present 2 Stimuli at Test - Novel Familiar
• Compare Test Performance of Each Stimulus to the
  Other

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Type of Information

• Auditory
• Mostly from mom
• But some from other
• Need to make sure not drowned out by the moms
  heartbeat and placental noises
• Taste and smell
• Material in amniotic fluid

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Early Findings

• Infants will suck a pacifier to hear their
  mothers voice over a strangers voice (DeCasper
  Fifer, 1980)
• Infants, whose mother read Cat in the Hat twice a
  day during last 6 weeks of pregnancy, sucked to
  hear Cat in the Hat over The King, the Mice and
  the Cheese (DeCasper Spence, 1986).
• Subsequent studies indicated that it was not the
  specific words of story that were learned by the
  fetus but the prosody (or rhythym).

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DeCasper et al. (1994)

• Similar to Cat in the Hat study
• Pregnant women read one of two childs rhymes
• Fetuses were tested 4 weeks after the reading
  began
• Tested with both rhymes read by a stranger
• Measured heart rate of fetuses

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Attention HR Richards (1988, 1991)

• Richards found that during attention-holding,
  which he called sustained attention, heart-rate
  decelerated
• Also found that infant is less likely to be
  distracted by a second stimulus when in
  heart-rate deceleration

Pre-Attention
Attention Termination
Orienting
Sustained Attention
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DeCasper et al. (1994)

• Hearing the target rhyme elicited a decrease in
  heart rate
• Indicating attentive processing
• Suggests that fetuses learn and become familiar
  with maternal speech sounds

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Lecanuet et al. (2000)

• Interested in the fetus ability to discriminate
  two musical notes (D4 vs. C5)
• Measured heart rate change when notes are
  presented

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Lecanuet et al. (2000)

• Infants who discriminated the notes, showed HR
  deceleration at the onset of each note
• Around 70 and 90 showed HR deceleration to the
  the first and second notes

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Menella et al. (2001)

• Most of the psychological work on prenatal
  learning has been concerned with auditory
  information
• However, fetuses get other types of sensory
  experiences, including taste

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Menella et al. (2001)

• Flavors of foods mom eats get into amniotic fluid
  and is consequently tasted by fetus
• Flavors similarly get into breast milk
• Had moms drink either carrot juice or water
  during pregnancy and then switched them to the
  other after birth
• Once infants began eating cereal, tested infants
  by mixing it with either water or carrot juice
• Measured infants reaction and mothers ratings

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Menella et al. (2001)

• These results indicate that infants exposed to
  the carrot flavor, even prenatally, preferred
  that taste than infants who did not

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Mizuno Ueda (2004)

• The odors of foods mom eats also gets into
  amniotic fluid
• These odors may then be learned by the fetus and
  subsequently affect breast feeding

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Mizuno Ueda (2004)

• Numerous studies that newborns can recognize
  their mothers odor at birth
• Interested whether preferences for maternal odors
  independent of postnatal experience play greater
  role in olfactory learning

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Mizuno Ueda (2004)

• Newborn infants were separated from mothers for
  10 to 14 days postnatally
• At test, infants given same formula with which
  they had become familiar
• But were presented with one of three odors
  mothers milk, formula, or distilled water
• Measured sucking pressure and frequency, and
  sucking efficiency

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Mizuno Ueda (2004)

• Solid line is expression pressure and dotted line
  is sucking pressure
• Sucking frequency and expression pressure are
  greater with mothers odor

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Mizuno Ueda (2004)
Sucking Pressure
Expression Pressure
Sucking Efficiency
Sucking Frequency
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Mizuno Ueda (2004)

• Thus, infants preferred their mothers odor which
  they had not experienced since they were in utero
• Suggests that the odor learning is quite strong
  in utero and carries more weight on infants
  olfaction and feeding than does postnatal
  experience

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Take Home

• These studies that learning does occur by the
  fetus in utero
• The fetus can learn about sounds, tastes, and
  odors
• They retain this information even after they are
  born

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Take Home

• However, what they learn is limited
• Typically, information that will promote caring,
  survival and attachment
• Furthermore, claims of supreme benefits on IQ,
  math ability and sociability of prenatal exposure
  to information are completed unsubstantiated by
  the research

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Questions

• One study showed that prenatal exposure to the
  mother's tongue can promote language-relevant
  perceptual tuning before birth. Would prenatal
  exposure to many languages provide an advantage
  for learning these other languages?
• If after a baby is born, the biological mother
  and the newborn are separated due adoption or
  death, will the newborn be delayed in terms of
  language and speech because the new maternal
  figure is not the same one that was stimulating
  and speaking to them when they were still in the
  uterus?

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Questions

• How would researchers explain children who at
  first do not like a certain food, but then learn
  to like it later on.
• Has there been any testing using fMRI to assess
  changes in activation in brain areas that might
  be affected by the prenatal exposure?