Question. Is the neonate a tabula rasa?

A neonate is "an infant during the first month of life" (Rathus, 1981, p. 367) or simply "a newborn child" (Reber, 1995, p. 487).

John Locke (1632-1704) was an English philosopher who founded the school of empiricism. Locke's empiricism emphasizes the importance of the experience of the senses in pursuit of knowledge rather than intuitive speculation or deduction. The empiricist doctrine was first taught by the English philosopher and statesman Francis Bacon early in the 17th century, but Locke gave it systematic expression in his Essay Concerning Human Understanding (1690). He regarded the mind of a person at birth as a tabula rasa, a blank slate upon which experience imprinted knowledge, and did not believe in intuition or theories of innate conceptions. Locke also held that all persons are born good, independent, and equal. Locke's influence in modern philosophy has been profound and, with his application of empirical analysis to ethics, politics, and religion, he remains one of the most important and controversial philosophers of all time (Encarta, 1997, Comptons, 1994).

Locke's philosophical opposite is often said to be Rene Descartes, a 17th-century philosopher who was the inventor of analytical geometry and was also regarded by many scholars as the father of modern philosophy. Descartes believed that the soul is immortal and capable of free choice, whereas the material world, including the body, is corruptible and subject to strict cause-and- effect relationships that are amenable to mathematical analysis. Another philosopher, George Berkeley, reduced the body and other matter into ideas generated by the omniscient mind of God, essentially eliminating matter. Yet another alternative was offered by David Hume, who denied both mind and body in favor of perceptions. According to Hume, even cause-and-effect relationships do not exist because they are metaphysical extrapolations from empirically based perceptions (Showbris, 1994).

Although modern science has found no evidence of the existence of either God or the human soul, it has discovered a great deal about the neonate. Science has not upheld any of the philosophies mentioned above and Locke's theory of the neonate being a tabula rasa has been cast into serious doubt.

The earliest behavior of any kind is the heartbeat, which begins at about three weeks (Zimbardo, 1988). During the first 18 months the average child makes considerable gains in height and weight, begins teething, develops sensory discrimination, and begins to walk and talk. Sensory acuity develops rapidly during the first three months of life. Research shows that newborns are capable of visual and auditory discrimination. By two days after birth infants can discriminate odors. Infants react to loud noises, and they probably possess taste discrimination. Babies can see from birth. Research since the early 1960s has shown that they tend to gaze into space with their eyes unfocused only because focusing on distant objects requires much effort. Babies focus most easily at a distance of about 10 inches (25 centimeters), so it is only when an object is brought close that babies will bother to look. Babies can hear from birth and may hear muffled sounds while still in the womb. In the first weeks, sudden sharp sounds usually frighten babies, while friendly human voices are both interesting and soothing. At first babies make few sounds other than crying, but this forms almost a language in itself. Within three months they can distinguish color and form and they show a preference for complex and novel stimuli as opposed to simple and familiar stimuli. Newborns perform motor movements, many of which are reflexive. Soon after birth they gain voluntary control of movements. The major stages of locomotion are crawling (propulsion using arms only), creeping (propulsion on hands and knees), and walking. The average infant walks between 13 and 15 months of age. Normal infants possess neurological systems that detect and store speech sounds, permit reproduction of these sounds, and eventually produce language. Infants utter all known speech sounds, but retain only those heard regularly. Word-like sounds occur at 12 months and have meaning at about 18 months. One- and two-word sentences are used to convey meaning. Early words generally include naming objects and describing actions, for example, "fall floor." Acquisition of complex language after 18 months is very rapid (Encarta, 1997, Comptons, 1994).

Every child is born with a number of reflexes. If the face of a neonate is gently held under water, the infant will not breath, but rather will slowly exhale and make swimming motions (Rathus, 1981). Other reflexes include the startle response, grasping an object placed in either hand, sucking, rooting, withdrawal from heat or pain, and the Babinski reflex--fanning the toes after stimulation of the foot. The neonate is "capable of perceiving the world reasonably well, even from birth" (p. 369).

But what occurs even before birth?

a. In the first half of the second month of gestation, the human embryo closely resembles that of other mammals, but in the latter part of the month the head becomes disproportionately large because of development of the brain. The external genitalia also appear in the latter part of the second month. The extremities become more developed, and the fetus attains a length of about 3 cm (about 1.2 in).

b. By the end of the third month, centers of ossification appear in most of the bones, the fingers and toes become differentiated, and the external genitalia begin to show definite sex differentiation.

c. After the fourth month the average fetus is almost 15 cm (almost 6 in) long and weighs about 113 g (about 4 oz). The sex of the fetus is easily identifiable. The face looks human, and movement is usually discernible.

d. During the fifth and sixth months a downy covering called lanugo develops on the body, and the body becomes increasingly larger in proportion to the head. The fetus attains a length of about 30 cm (about 12 in) and weighs about 624 g (about 1 lb 6 oz).

e. During the seventh month the skin, which is red and wrinkled, is covered with a white substance called the vernix, or vernix caseosa, which protects the skin. The vernix is a mixture of epithelial cells, lanugo hairs, and secretions from the glands of the skin. By then the fetus is about 40 cm (about 15 in) and has attained a weight of more than 1 kg (more than 2 lb). The pupillary membrane disappears from the eyes. The body organs are sufficiently developed to sustain life outside the uterus; the more developed the fetus, the greater are its chances for extrauterine life. A fetus born at this period moves its limbs quite energetically and cries with a weak voice.

f. During the eighth and ninth months, the fetus loses its wrinkled appearance due to the deposition of subcutaneous fat. The fingers and toes have well-developed nails.

g. Full term is reached at the end of the tenth lunar month of pregnancy. Most of the fetal hair has been shed, and the fetus is ready for birth, having attained a length of about 50 cm (about 20 in) and a weight of approximately 3 kg (approximately 7 lb). The vernix covers the entire surface of the body. When the infant is born before the full term and weighs less than 2.4 kg (5 lb 8 oz), it is considered premature (Encarta, 1997, Comptons, 1994).

Respiratory activity occurs in the fetus as early as the twelfth week of gestation and continues throughout its intrauterine life. The lungs do not function in any effective sense, however, because the fetus is enclosed in a sac that fills with a clear amniotic fluid early in the embryonic period. Oxygen and materials needed for nutrition are brought to the fetus from the placenta, a vascular organ which unites the fetus to the maternal uterus, by the umbilical vein (Encarta, 1997, Comptons, 1994).

New evidence indicates that within the brain of the developing fetus are waves of neural activity and that those pulsing waves are "like currents shifting sand on the ocean floor, actually change the shape of the brain, carving mental circuits into patterns that over time will enable the newborn infant to perceive a father's voice, a mother's touch, a shiny mobile twirling over the crib" (Nash, 1997, p. 49). Of all the discoveries that have come from the neuroscience labs in recent years, the finding that the electrical activity of brain cells changes the physical structure of the brain is perhaps the most breathtaking. The rhythmic firing of neurons is no longer assumed to be a by-product of building the brain but is essential to the process, and it begins, scientists have established, well before birth. The brain does not fully form and then begin to function, but rather it begins working long before it is finished. And the same processes that wire the brain before birth also drive the explosion of learning that occurs immediately afterward (Nash, 1997).

At birth a baby's brain contains 100 billion neurons, roughly as many nerve cells as there are stars in the Milky Way. Also in place are a trillion glial cells, named after the Greek word for glue, which form a kind of honeycomb that protects and nourishes the neurons. At birth, the brain contains virtually all the nerve cells it will ever have. However, the pattern of wiring between them has yet to develop and stabilize. It is like a blueprint that sensory experience after birth will progressively refine (Nash, 1997).

During the first years of life, the brain undergoes a series of extraordinary changes. Starting shortly after birth, a baby's brain produces trillions more connections between neurons than it can possibly use. Then, through a process that resembles Darwinian competition, the brain eliminates connections, or synapses, that are seldom or never used (Nash. 1997).

The figure above  shows the results of a study between male and female day-old infants. Female infants show a clear preference for familiar odors while male infants do not show any preference. "The findings for females suggest that they are capable of differentiating between odors at birth or very shortly thereafter" (Baron, 1989, p. 98).

Observations of temperament from the neonatal period to later development have provided evidence of constitutional influences on temperament development. Several studies have demonstrated relationships between various aspects of temperament observed during the neonatal period and behavior observed in later infancy. Birns, Barten, and Bridger (1969) found a relationship between irritability and sensitivity when measured at 2 or 3 days of age and again at 4 months of age. Administration of the Neonatal Behavioral Assessment Scale (Brazelton, 1973) at 5 days of age and observation of mother-infant interaction at approximately 9 months demonstrated a relationship between 5-day irritability and 9-month social behaviors (Fish & Crockenberg, 1981). Isabella, Ward, and Belsky (1985) found relationships between neonatal habituation and the range of state with mothers' ratings of dullness for their 3-month- old infants, between neonatal state regulation and autonomic stability with mothers' 9-month ratings of fussy-difficultness, and between neonatal exhibition of physiological stress and 9-month ratings of predictability. A comprehensive assessment of neonatal temperament has demonstrated predictive relations from neonatal irritability, resistance to soothing, activity level, reactivity, and reinforcement value to laboratory assessments and mothers' ratings of temperament through 30 months of age (Matheny, Riese, & Wilson, 1985; Riese, 1987, 1992; Riese, Wilson, & Matheny, 1985). These and other studies strongly suggest that an infant's ability to be soothed is a component of temperament that has a constitutional basis and, therefore, is predictive of later temperament. This, in turn, suggests that the neonate has an individual temperament and is not a tabula rasa at all.

Jung (1954) spoke against the theory of Locke and wrote that "The child's psyche, prior to the stage of ego-consciousness, is very far from being empty and devoid of content" (p. 44). And Zimbardo (1988) concludes that "the extreme position of Locke ... [does] injustice to the richness of behavior" (p. 69). The "extreme position of Locke" says that all behavior is the result of our learning and experiences. If every child is born equal and with an "empty" brain, then all behavior and personality characteristics must be learned. However, this position is countered by the opposite extreme-that all behavior and personality characteristics are inherited, an idea that stemmed from the rationalism of Renè Descartes (Zimbardo, 1988). These oppositional viewpoints are known as the nature versus nurture controversy.

Today, modern psychology has ended this controversy by agreeing that both nature (genetic factors) and nurture (environmental factors) are both in operation together. "Heredity sets the upper limits of development; experience and practice determine how closely the limits are approached" (Zimbardo, 1988, p. 69).

Only 15 years ago, neuroscientists assumed that at birth a baby's brain structure was genetically determined. Now it is widely believed that a newborn's brain is much more active, complex and formable. For the first decade of life, children's brains are more than twice as active as adults' brains. Human development hinges on the interplay between nature and nurture. In the old debate, there's a new conclusion: It's nature and nurture. Both are crucial. How humans develop and learn depends upon the interplay between genetic (nature) and environmental (nurture) factors (Rubiner, 1997).

Our brain is not a tabula rasa on which anything can be imprinted. The central nervous system has tendencies that are reflected in a gravitation toward particular behaviors partly expressed in our rituals, mythologies, religions, and social structures. Superimposed on this biological backdrop is an equally inherited ability to reason. Reason appears to be possible because built-in feedback loops create a hierarchical progression with the capacity to always look back at previous levels of integration (Showbris, 1994, p. 386).

The modern argument against the theory of the tabula rasa is mainly based upon solid scientific evidence from studies addressing physiology, neurology, and psychology. The brain of the neonate is not empty. Rather, it contains the blueprint or limitations for all future possible development. Individual development, based upon this blueprint, is largely determined by experience. The nature-nurture controversy that developed from the theories of Locke versus Descartes now seems resolved-both are required and both take part in human development.

References

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Birns, B., Barten, S. & Bridger, W. H. (1969). Individual differences in temperamental characteristics of infants. Transactions of the New York Academy of Sciences. 31. 1071-1083.

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Riese, M. L., Wilson, R. S., & Matheny, A. P., Jr. (1985). Multimethod assessment of temperament in twins: Birth to six months. Acta Geneticae Medicae et Gemellologiae. 34. 15-31.

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