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Learning is defined as the modification of behavior by
experience (12.). For learning to take place, both the ability to
experience the outside world through the senses, and the ability to
record these experiences through memory, are necessary. |
Development of the senses and of the brain are prerequisites to
prenatal learning. Without the physical equipment necessary to interact
with the environment, and the neural equipment necessary to process the
information acquired, no learning can take place. The development of the
senses is a gradual process, and it is difficult to determine precisely
when the embryo actually begins to receive information in the form of
sensation and respond to it deliberately, and when a response is purely
reflexive. The pattern of development of the embryonic heart may be
indicative of how the development and use of other organs progresses.
The heart begins pumping blood as soon as a single chamber is able. The
organ begins to function long before its completion, with the rest of
the circulatory system added as it is needed ( 3.). It is reasonable to
assume that the development of the central nervous system and the senses
follow this pattern.
The embryonic brain, like the heart, develops in a pattern of
increasing complexity. The first neurons are formed out of the ectoderm,
one of the three cell layers present in the very early embryo. These
cells fold inward and form a nerve cord. These cells differentiate into
central and peripheral nerve cells ( 8. ). Those cells that become the
central nervous system form the neural tube, the beginning of the brain
and spinal cord, during the fourth week ( 13.). Most of the neural tube
forms the spinal cord, but the anterior end of the neural tube folds
forward and begins to form the brain. |
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The embryonic brain then proceeds to develop into three regions: the
prosencephalon, or forebrain, the mesencephalon, or midbrain, and the
rhombencephalon, or hindbrain ( 8. ). The forebrain forms two major
divisions, the telencephalon and the diencephalon. This division occurs
in the seventh week of gestation. The telecephalon becomes the
cerebrum,
and the diencephalon becomes the thalamus, the hypothalamus, and the
pituitary. The midbrain becomes the parts of the brain that process
visual and auditory information, as well as connecting other brain
regions and coordinating reflexes. The hindbrain forms the cerebellum,
pons, and medula -- known collectively as the brain stem. These brain
regions control basic bodily functions; the cerebellum also serves to
coordinate brain impulses and physical behavior ( 12. ). By eight weeks,
all the basic parts of the brain are in place( 1. ), as are all other
organs as the unborn child leaves the embryonic stage of development and
becomes a fetus ( 6. ). However, the brain is by no means complete;
brain cells continue to be formed into the fifth month of gestation (
11. ).
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| With the use of an electroencephalogram, or EEG, activity in the
brain can be detected as early as six weeks gestational age ( 6. ).
Whether brain activity begins at this time or merely becomes detectable
at this time is uncertain; it is known that neural connections begin
forming as soon as neurons begin forming, as early as 14 days gestation
( 9. ). |
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The embryo develops reflexes ( 13. ) and is capable of motion ( 3.)
as early as the sixth week of gestation, and by eight weeks the
Association for Pre- and Peri-Natal Psychology and Health states that
these movements show evidence of being voluntary rather than reflexive.
These movements, early in gestation, are spontaneous and endogenous. The
embryo is capable of responding to stimulation, but more frequently
moves for no outwardly apparent reason ( 3. ). Dr. Harley Smyth, a
neurologist, testified before the Canadian Supreme Court that "at 6
weeks [gestational age - 8 weeks gestation or LMP] there is the
possibility of recording electrical activity from the nervous system
already so highly organized that it can subserve . . . purposeful and
even co-ordinated movements." (5.) At six weeks development, there
is no motor cortex in the brain, the cerebellum has not been
differentiated from the rest of the hindbrain, and the spinal cord is
incomplete. Yet motion occurs, and thought may also be beginning. This
gives evidence to the theory that, rather than forming and then
beginning to function, embryonic organs function as they form. Learning,
therefore, may begin to take place far before the brain structures
traditionally thought to be necessary for conscious thought are present.
Embryonic senses allow interaction with the environment as early as 6
weeks gestation, when an embryo will respond to a stroking of its cheek
( 3.). The embryo will arch its back and push back its head ( 10. ).
Sensitivity to touch spreads gradually through the body. By 8 weeks, the
embryo shows evidence of sensation in the genital area, in the palms of
the hands by 9 weeks, and the soles of the feet by 10 weeks. By 15
weeks, the entire torso is sensitive to touch ( 3. ).
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The structures needed to experience taste are developed by 12 weeks,
and the sense of smell develops gradually between 9 and 13 weeks . Many
chemical compounds and products of the mother's diet cross the placenta,
providing the fetus with a changing range of tastes and smells. Research
shows that a fetus will swallow more amniotic fluid when a sweet taste
is present than when a sour taste is introduced to the womb ( 3. ).
Reactive listening has been demonstrated through research at 14 weeks
gestational age, approximately 8 weeks before the ear is structurally
complete. Researchers in Belfast demonstrated this by beaming a pure
pulse sound into the womb at various gestational ages; a visible
reaction was first demonstrated by the fetuses and observed by
ultrasound at 14 weeks. Other studies have demonstrated that a
five-second auditory stimulus can cause a change in heart rate that
lasts up to an hour ( 3.).
Vision, while well developed in premature infants, cannot be readily
tested in the womb. It has been demonstrated, however, that the fetus
reacts to light with an acceleration in heart rate ( 3. ).
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There is some evidence that the fetus experiences pain, as well as
emotional responses such as anger or pleasure, at least as early as 14
weeks, when amniocentesis is performed. During fetal blood transfusion,
a 590% rise in beta endorphin and a 183% rise in cortosol have been
documented in the fetus. The presence of both of these hormones in such
high levels, as a response to a stimulus, is chemical evidence of pain (
3. ). Fetuses respond in a variety of ways to amniocentesis, from shying
away from the needle to kicking at it ( 4. ). The variety of responses
in different fetuses of the same age to the same experience seems to
indicate that these responses are not instinctual, but individual
responses of fear, curiosity or aggression. A fetus will experience
fluctuations in heart rate during and immediately following
amniocentesis, and breathing motion patterns may not stabilize for days.
Ultrasonographers have observed male fetuses experiencing erections as
early as 14 gestational weeks in conjunction with thumb-sucking, which
may give evidence to the fetus's ability to experience pleasure ( 3. ).
These emotional responses, taking place before the limbic system is
fully formed and long before the cerebral cortex, thought to be
responsible for conscious thought, is completed, are further evidence
that the brain is functioning long before its individual structures are
complete.
Anecdotal evidence for prenatal learning abounds. A professional
cellist and conductor found to his amazement that he knew the cello part
to several pieces perfectly --
despite having never seen the music
before. His mother, also a professional cellist, had practiced those
pieces while pregnant ( 11. ). Twins appear to learn patterns of
interaction that they carry with them throughout their lives. In one
case "brother and sister were seen playing cheek-to-cheek on either
side of the dividing membrane. At one year of age, their favorite game
was to take positions on opposite sides of a curtain, and begin to laugh
and giggle as they touched each other and played through the curtain.
" ( 2. ). Some parents claim to have taught their unborn children
to kick on request, but using verbal association when the baby kicks on
his or her own ( 2. ). Research into prenatal learning and other facets
of prenatal awareness often simply confirm what many parents believed
already, that it is possible to interact with a child before birth.
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There is also much clinical evidence for prenatal awareness and
learning. Most of the research done into prenatal learning has dealt
with auditory learning. Conclusive evidence that newborns recognize
their mother's voices has been presented by Anthony DeCasper, a
psychologist at the University of North Carolina. Dr. DeCasper had
expectant mother read 'The Cat in the Hat' to their fetuses at regular
intervals before birth. The results were clearly indicative of learning
prior to birth; "At birth, babies were hooked up to recordings
which they could select by sucking on a non-nutritive nipple. After a
few trials, babies cleverly sucked at whatever speed was necessary to
obtain their mother's voice reading "The Cat in the Hat." ( 2.
).
Fetuses also learn the beginnings of languages from their mothers
while in the womb. Research using acoustic spectroscopy has shown that,
at 27 weeks, a baby's cry already contains some features of his or her
mother's speech, such as rhythms and voice characteristics. Newborns
show a preference for their mother's language; French babies prefer to
watch someone speak French, while Russian babies show a preference for
Russian. A French experiment conducted on fetuses 33 to 37 weeks
gestation demonstrated memory of a children's rhyme, while still in the
womb. During the course of the experiment, the mothers read a certain
rhyme to their unborn children daily; at the end of this time, the
fetuses displayed recognition of this rhyme over other rhymes they had
not heard ( 2. ).
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A study by Donald Shelter, professor of education at the University
of Rochester's Eastman School of Music, shows that fetuses are also
capable of remembering a wordless tune. This study also
gives evidence
to the positive effects of prenatal exposure to complex rhythms. In this
study a stereo earphone system was placed directly on the mother's
abdomen, allowing the fetuses to list to orchestral music with a single
dominant melody. After two years, most of the thirty participants were
able to recognize that melody. In addition, these children showed very
advanced speech ability ( 11. ). The positive effect of this experiment
on its subjects suggests that prenatal teaching is not only possible but
beneficial.
This research provides conclusive evidence to prenatal learning
taking place in the second and third trimesters. However, little
research appears to have been done on the possibility of learning
earlier than 14 weeks and the onset of hearing. This is most likely due
to the difficulty in providing other sorts of stimuli, and also of
measuring the very young fetus's response. However, the developmental
pattern present in the senses and other organs indicates that the brain
may be functioning very early in pregnancy. Voluntary motion and
emotional responses to stimuli indicate that the fetus is to some degree
conscious. It seems likely that learning can and does take place from
very early in gestation.
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1. Chamberlain, David, ed.. "Early and very early parenting:
parents ask about life inthe womb." Life before birth.
http://www.birthpsychology.com/lifebefore/early3.html
(17 Nov. 1998).
2. Chamberlain, David, ed.. "Prenatal memory and learning."
Life before birth. http://www.birthpsychology.com/lifebefore/earlymem.html
(8 Nov. 1998).
3. Chamberlain, David, ed.. "The fetal senses." Life
before birth. http://www.birthpsychology.com/lifebefore/fetalsense.html
(8 Nov. 1998).
4. "Communication before language." Life before birth.
http://www.birthpsychology.com/lifebefore/comm.html
(15 Nov. 1998).
5.) Evidence of Dr. Harley Smyth (Position), Borowski v. The Attorney
General of Canada 8C.C.C. (3d) 1983; See Trial for Life, Vol. 1,
Alliance Against Abortion, Winnipeg, 1984, Testimony of Dr. Harley
Smyth, p. 492.
6. Houp, Katherine H. "Embryology." Piotrowski,
Nancy A., ed. v. 4 Magill's medical guide: health and illness suppliment.
Salem Press; 1996. pp. 1069-1073.
7. "Milestones in fetal development." Human development.
(24 Nov. 1995). http://www.ohiolife.org/develop/mileston.htm
(15 Nov. 1998).
8. "Neurology." Piotrowski, Nancy A., ed. v. 4 Magill's
medical guide: health and illness suppliment. Salem Press, 1996. pp.
1397 - 1400
9. Nilsson, Lennart. A Child is Born. New York: Dell Publishing,
1993.
10. Papalia, Diane E.; Olds, Sally Wendkos. A child's world: infancy
through adolescense. New York: McGraw Hill, 1990.
11. "Prenatal learning and development."
http://www.compufix.com/zenith/Hist.htm
(11 Nov. 1998).
12. Purves, William K.; Gordon, H. Orians, H; Heller, Craig H.;
Sadava, David. Life: the science of biology. Salt Lake City, UT: Sinauer
Associates, 1998.
13. Ross, Anna E. "Summary of prenatal fevelopment." Dr.
Ross' Vertebrate Embryology Course (Bio 211): Contents of Unit 2
Embryology Lecture Notes. (Fall 1996).
http://www.cbu.edu/~aross/emlec-u2.HTM#Summary_of_Prenatal_Development
(5 Nov. 1998).
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