A rough summary of the landmarks of neurophysiological and psychological development, with sources of data (all from human subjects), during human perinatal life by month of postpartum age.
Month Week What Is Known About Brain and Consciousness:
0 0 -Birth is an intense experience of transformation (Stave in Stave 1978); bonding with mother before and just after birth (Sugarman 1977, Chamberlain 1983: 17, Brazelton and Als 1979, Liedloff 1975, Ainsworth 1967, Ainsworth et al. 1972, Bowlby 1969, Eibl-Eibesfeldt 1983, Trevathan 1987); recognition of mother's voice demonstrated (Busnel and Granier-Deferre 1983, DeCasper and Fifer 1980); born with innate capacity for interpersonal communication (Trevarthen 1983b); foveal vision immature relative to peripheral vision (Banks and Salapatek 1983), but multimodal perceptual coordination in exploration of environment (Field 1987); able to discriminate and imitate facial expressions (Meltzoff and Moore 1983a, Field et al. 1982); facial expression of positive and aversive response to tastes (Steiner 1979); cerebral hemispheres anatomically asymmetrical (Witelson and Pallie 1973); behavioral and electrophysiological asymmetries (Turkewitz and Creighton 1975, Molfese 1977); slight right hand bias from birth in dextrals (Bates et al. 1986).
1 -Recognize and prefer mother's smell (McFarlane 1975).
2 -Recognize their mother's picking them up in the dark and silence (Widmer cited in Murray and Trevarthen 1985).
3 -Typical adult pattern of lateral asymmetry for speech and nonspeech sounds present by 22 days, but possibly from birth (Entus 1977).
1 4 -May be visually sensitive to kinetic flow-field information about impending collision with an object (Yonas and Granrud in Mehler and Fox 1985).
6 -Evidence of ability to perceive spatial structure of visual objects (may be present from birth; Cook 1987); sensitivity to complex nuances of communicative and emotional states in mother by this age or earlier (Murray and Trevarthen 1985).
2 8 -Evidence of phonetic discrimination (Busnel and Granier-Deferre 1983); evidence of bimanual haptic exploration of objects (Streri and Spelke 1988); great proliferation of cortical dendritic spines, many of which are later lost (Banks and Salapatek 1983: 453).
9 -Emotional expression by facial expression, vocalization and gesture; intensely involved in interpersonal engagement (Trevarthen 1983b) involving "turn-taking" between mother and infant (Mayer and Tronick 1985).
13 -Significant right hand bias established, stronger for symbolic, as opposed to nonsymbolic movements (Bates et al. 1986).
4 16 -Visual stereopsis and equalized optokinetic responses adult-like (Held in Mehler and Fox 1985); binocular summation of pupillary response (Birch and Held 1983); visual accommodation now more like adult (Haith 1980: 122); knowledge produced by bimanual haptic exploration is transferred cross-modally to vision (Streri and Spelke 1988).
18 -Size of visual objects remains constant with varied distance (Day 1987).
5 20 -Evidence of object permanence (Spelke and Kestenbaum 1986, Baillargeon, Spelke and Wasserman 1985).
23 -Pictorial depth information (Yonas and Granrud in Mehler and Fox 1985)
The Perinatal Sensorium.
The perinatal sensory system is comprised of developing networks of interconnecting cells that have already begun to function in prenatal life as soon as they are in place. At no time is the sensory system producing a chaos of random sensations as was once believed (and at least tacitly implied by some current writers; see Maurer and Maurer 1988: 51). Rather,
In recent years, it has become abundantly clear that William James' ...characterization of the world of the infant as a "blooming buzzing confusion" is simply wrong. There is evidence that the infant's world is structured and that far from being overwhelmed by a barrage of stimulation which only slowly comes to be sorted out, the infant from his earliest days is quite properly characterized as competent and organized. It is our contention that one of the major sources for this organization is the infant's limited sensory capacity.
(Turkewitz and Kenny 1982: 362)
This is a crucially important fact: most available evidence suggests that there exists no stage of development, prenatal or perinatal, in which the cognized environment of the child is in chaos. It is ordered from first to last (e.g., see Blakemore 1974 on the development of the visual system). Sensory organization emerges during development mediating an ever ordered, yet ever more complex and more flexible field of perception. And as the sensorium develops, particularly at the subcortical levels, well before higher cortical functions, the order inherent in primitive perception is ontogenetically the primary order in human experience. In other words, the primacy of the order of perception in consciousness holds not only for adult experience (as Merleau-Ponty 1964, 1968 repeatedly emphasized), but for ontogenesis as well (see Laughlin 1985). Moreover, it is now clear that there is continuity in the development of cognitive functions operating upon sensory objects from at least birth onward (Bornstein and Sigman 1986, Fagan 1984c).
The visual system of the infant, although it is the last to begin developing in the womb, is nonetheless fairly precocious at birth (Haith 1980). The infant soon after birth is found to have a fully functioning pupillary response over a wide range of light intensities, if somewhat nearsighted by adult standards. The infant can scan (with both eyes in sync, but with immature convergence) the visual field in moderate illumination and in the dark, will fixate upon objects of interest (particularly the edges of things), inspect them avidly, and follow their movements. Objects are cognized by the detection of invariant features, including movement (Burnham 1987). They have both foveal and peripheral vision, saccadic movements, and the internal visual pathways and cortical association areas requisite to learning. Haith (1980: 119) suggests that "the newborn's visual activity can be understood in terms of a system that serves to keep visual cortical-firing rate at a high level." In other words, the newborn is already prepared to explore its environment, and detect, explore and model objects and relations found there. In fact, some researchers go so far as to suggest that object perception develops early and that the infant at, or near birth is perceiving the world out of a single mechanism, an already mature "object concept" (Streri and Spelke 1988) from which it explores the surfaces and movements of objects in its environment.
The infant appears to require several months before it is capable of fully binocular experience and extraction of information (Imbert in Mehler and Fox 1985), well coordinated selectivity and attention control (Braddick and Atkinson 1988), and the kind of memory processing characteristic of later infancy (Olson and Strauss 1984). However, within a couple of months after birth at the latest, the infant is perceiving objects that extend behind other objects, and by five months can perceive them as continuing to exist when lost to view (Kellman and Spelke 1983, Baillargeon, Spelke and Wasserman 1985, Spelke and Kestenbaum 1986). From at least the time of birth, infants are thought to discriminate colors and sounds on the basis of perceptual categories mediated by innate neural structures maturing during gestation (Wilson in Harnad 1987).
The Other Senses
The perinatal cognized environment is also rich in gustatory, auditory and tactile sensations, as well as somaesthetic sensations of intrinsically initiated movements (see Ganchrow, Steiner and Daher 1983, Steiner 1979, Barlow and Mollon 1982, Busnel and Granier-Deferre 1983). Of particular importance to anthropologists is the infant's interest in, and ability to discriminate speech sounds in a manner similar to that of adults (Eimas and Corbit 1973, Cutting and Eimas 1975, Eimas in Mehler and Fox 1985, Eimas, Miller and Jusczyk in Harnad 1987, Jusczyk in Mehler and Fox 1985, Aslin, Pisoni and Jusczyk 1983). The newborn's cerebral hemispheres are distinctly anatomically asymmetrical (Witelson and Pallie 1973) and Molfese (1978) has presented electrophysiological data showing that left hemisphere response to speech sounds is greater than for non-speech sounds. Newborns have been shown to prefer speech sounds to sounds made by non-human objects, and female voices to male voices (Eisenberg 1975), and to extract information about emotional expression from intonation (Trevarthen 1983a).
Abstract Perceptual/Cognitive Associations
Although their functioning seems primitive, the infant between birth and about four months of age is nonetheless equipped with the perceptual structures in place to apprehend substantial, physical objects, their unities, their boundaries, their constituent parts and their continuity during displacement (Spelke 1988a, 1988b, and in Mehler and Fox 1985). Some researchers have suggested that perhaps by late intrauterine life, by birth, or certainly by four months of age the child is equipped with innate higher perceptual and cognitive structures that anticipate a three dimensional and temporal/causal world that becomes fulfilled and refined in actual perceptual experience as it arises in the sensory system (see Gibson 1969, Treiber and Wilcox 1980, Bower 1974, Bower and Wishart 1979, Meltzoff and Borton 1979, Antell and Keating 1983, Banks 1988, Spelke 1988b, Leslie 1988, Gottlieb 1976a). And this fulfilment may include a fundamental evaluation of the object as being positive or negative, pleasurable or displeasurable (Lipsett 1979, Steiner 1979).
Developing perceptual structures project redundancy upon the perceptual field; that is, the experience of most of the perceptual field is of recognition and a corresponding lack of novelty. We know that neonates and infants are conscious of and learn from perceptual novelty in their environment (Rovee-Collier and Lipsitt 1982, Sameroff and Cavanaugh 1979). Individual differences in attention to novel, as opposed to previously experienced visual objects, as well as other attention-related factors, have been found among infants, and these have been shown to be predictive to psychometric intelligence later in childhood (Fagan 1984a, 1984b, 1984c, Fagan et al. 1986, Lewis, Jaskir and Enright 1986, Hollenbeck et al. 1986, Rose, Feldman and Wallace 1988, Colombo, Mitchell and Horowitz 1988). Joseph Fagan has hypothesized that this continuity of intelligent processing may be mediated by "a small set of processes for knowledge acquisition that are innate, that underlie g, and that provide the basis for continuity in intellectual functioning during development" (1984c:21). The intelligent neonate and infant seem to be curious about their world and especially about novelty; this despite the well known altriciality of their behavior (Zelazo 1979, Moss et al. 1988, Trevathan 1990). Long-term memory of visual objects is present at birth and increases dramatically during the first weeks after birth; e.g., recognition of faces, visual patterns, objects and speech sounds (Ungerer, Brody and Zelazo 1978, Fagan 1984c).
Associations are not merely limited to single sensory modalities, for infants are quite capable of multimodal perceptual associations (Dodd 1979, Spelke 1979, Kuhl and Meltzoff 1988) and synaesthesia ("seeing" sounds, "hearing" colors, etc.; Lewkowicz and Turkewitz 1980). This supramodality of perceptual categories and associations is just as one would expect if higher, more abstract perceptual structures are indeed in place by birth. And as the nervous system, even during prenatal life, is developing in intimate dialogue with the external environment, the question of the role of culture in influencing the development of these perceptual and cognitive structures is clearly indicated (see Bornstein in Mehler and Fox 1985).
The Social Cognized Environment of the Perinatal Child
The preparedness of the neonatal perceptual/cognitive system for learning is not limited to physical objects and relations in the environment. The infant is inherently and actively social in its activities, and participates fully in socially related learning (Papousek and Papousek 1982). Humanity is a social primate, and the early development of a human being must always be considered within its social context. The fetus/infant is socially dependent, while at the same time being an autonomous, self-regulating organism. The infant exercises its precocity within the social constraints imposed by parents, siblings and other caregivers.
It is no surprise, therefore, that a major mechanism of social learning for the infant is imitation. This is learning about social interaction by doing and the structures for inculcating perceived gestures and facial expressions may prove to be present at birth (Meltzoff and Moore 1977, 1983a, 1983b). As Meltzoff and Moore (in Mehler and Fox 1985: 140) note, imitation is ubiquitous to human learning cross-culturally. Research on this capacity of neonates is just beginning and conclusions should be treated as tentative (Over 1987).
However tentative, the research results thus far (see Meltzoff 1985) do support the notion that the newborn human being is neurocognitively active and aware, and prepared to recognize significant social events in the environment. Moreover, the newborn and infant is able to learn appropriate responses in relation to rewards via something like a "contingency analysis" (Watson 1967). In phenomenological terms, not only is the primacy of perception the rule for neonates in ordering the physical cognized environment (a la Maurice Merleau-Ponty 1964), it is also the rule in ordering the social cognized environment (a la Alfred Schutz and Thomas Luckmann 1973). That is, not only is the world of physical objects neurognostically "already there" to the neonatal perception at, or before birth, so too is the world of socially significant objects and interactions -- objects that include speech sounds or vocal vibrations, interactive gestures, emotional expressions and faces, and especially the face, gestures, emotional expressions, smell, physical touch, breasts and voice or vocal vibrations of its mother (Field 1985, Murray and Trevarthen 1985, Butterworth and Grover 1988).
And these socially relevant objects receive characteristic bivalent emotional responses by the infant (Schneirla 1959, Lipsitt 1979, Bowlby 1969, 1972, Ainsworth 1967, 1979, Ainsworth, Bell and Stayton 1972) possibly indicating an innate proclivity to seek out social interaction, and avoid separation, isolation and potentially dangerous strangers. Various evidence suggests that "seriously deviant patterns of childrearing" (Lamb et al. 1985:272) such as parental abuse and neglect may produce profound and potentially long-term negative effects upon personality organization, affective orientation and patterns of adaptation (various references in Murray and Trevarthen 1985: 192; also Ali and Lowry 1981). Caution needs to be exercised when considering attachment, however, because detailed conclusions about exactly what interactions between the infant and its caregivers produce what variations in bonding behavior are not yet possible due to methodological problems (see Myers 1987 and Lamb et al. 1985 for methodological critiques of attachment theory). Moreover, it seems evolutionarily reasonable that the drive to bond is ecologically plastic to some extent (Lamb et al. 1985:274, Tronick, Morelli and Winn 1987).
The inborn proclivity for social interaction is, as we have seen, reflected in the infant's preparation to explore and produce speech sounds. It was until recently thought that older infants passively receive language enculturation and that their early babbling is meaningless and bears no relation to the later development of "real" speech. This view has currently been reversed (at least in developmental psycholinguistics) and the best recent evidence indicates that infant vocalization and babbling are constituted by both genetically endowed and culturally labile features, and that they are a consequence of both an active intent on the part of the infant to communicate on the one hand, and the willingness of adults to interpret their vocalizations and behavior as meaningful and to engage in dialogue with them on the other hand (Waterson and Snow 1978, Bullowa 1979, Murray and Trevarthen 1986). Oller et al. (1976) have shown that some of the phonetic content of babbling exhibits similar preferences to that found in later child speech, depending upon the language spoken. De Boysson-Bardies, Sagart and Durand (1984) partially confirm this finding by showing that adult speakers of different languages can accurately distinguish the recorded babbling of infants raised in their particular language group by recognizing certain metaphonological characteristics.
Furthermore, the form and content of adult babytalk has been shown to be determined by cultural attitudes and relations operating elsewhere in the culture (Blount 1972, in Snow and Ferguson 1977: 301, Goldman 1987), and to involve simplification and reduction of form (Ferguson in Snow and Ferguson 1977, Papousek, Papousek and Bornstein 1985). The data on many societies show that the mother is not the sole linguistic influence on the infant, influence coming frequently from an extended group of siblings and other kin (Blount in Snow and Ferguson 1977: 299).
NEUROGNOSIS AND ENCULTURATION
Summarizing from the wealth of data now being accumulated about early human neurocognitive development, the pre- and perinatal brain appears to be neurognostically prepared to carry out a program of self-regulated development which involves active exploration of the operational environment that: (1) is capable of seeking out, examining and learning about physical objects, (2) may be capable of constructing memories about life in the womb, about birth and about events occurring in postnatal life (this is sofar hard to verify apart from clinical evidence), (3) is neurognostically predisposed to be interested in faces and speech sounds, (4) is inherently social in its synchronized interactions and communications with caregivers,11 (5) is capable of constructing supramodal models of physical and social objects, (6) probably (although as yet hard to be sure) is engrossed much of the time in a symbolically rich dream-state cognized environment,12 and (7) is cognitively and perceptually precocious relative to its behavioral altriciality (see Trevathan 1987, n.d., Fagan 1984b, 1986).
None of this should be surprising to those who understand that much of what has made the evolution of the human brain so distinctive has been the emergence of precisely those areas of neural tissue subserving the construction of a cognized environment (see Sarnat and Netsky 1974, Jerison 1973, Laughlin and d'Aquili 1974, Laughlin, McManus and d'Aquili 1990). The cognized environment is essentially a system of neural structures that models the world and portrays that modelled world before itself in experience. Neural models, being made of living cells, always develop under the constraints imposed by fundamental and essential neurognostic principles. Of course, the adaptive advantage of the cognized environment is to be found in its structural flexibility which allows, within these neurognostic constraints, an enormous range of organizations to selectively stabilize relative to a remarkable variety of operational environments (Piaget 1971, 1985, Waddington 1957, Changeux 1985, Edelman 1987, 1989, Chisholm 1983, Gottlieb 1976a, 1976b, Bateson 1976, Simon 1981, Kagan 1989).
However, because anthropologists are typically uninformed from either the neurosciences or the various fields of pre- and perinatal psychology, all of these considerations raise a serious set of questions for ethnology: Does enculturation -- i.e., how new and traditional skills and ideas are learned by individuals during the course of life (Herskovits 1948: 37-45) -- begin earlier in life than was previously thought? Are the roots of enculturation to be found in development-environment relations during pre- and perinatal life? Does culture actually begin to have an influence upon the child while it is still in the womb, and does this influence accelerate during the first months after birth? These questions are difficult, if not impossible to answer by reference solely to ethnology, for it is precisely the pre- and perinatal period of life for which traditional ethnological theory has had little interest and for which ethnography has produced scant direct data (see Trevathan 1987, Laughlin 1989, Chisholm 1983, Chisholm and Heath 1987).
Indeed, part of the problem may be found in the connotation of the term "enculturation" itself, for it generally implies the transmission of totally learned patterns of cognition and behavior associated with "nurture" (e.g., social roles, speech patterns, behavioral skills, patterns of thought, etc.) structured at a level far exceeding the capacity of a pre- and perinatal human being (who is associated with "nature;" see Piaget 1971, Oyama 1985, Varela 1979, Laughlin and d'Aquili 1974). The usually tacit presumption in applying the term is that "enculturation" (i.e., "nurture") begins later in childhood when culturally particular "child-rearing practices" (e.g., toilet training, weaning, parent-child separation, etc.) come into play.
As a consequence of the "nature/nurture" dichotomy inherent in ethnological thinking, there are a number of theoretical and methodological problems that have hampered the production of ethnological theory and ethnographic data about early enculturation (see Laughlin 1990 for a discussion of these). For example, no clear understanding exists in ethnology about the relations between culture ("nurture") and neurological development ("nature;" see also Super 1987). Indeed, classical thinking in anthropology excluded the development of the brain altogether in favor of the passive transmission of traits from adults to children. But most of the simple relations once thought by psychological anthropologists (see Whiting and Child 1953) to exist between discrete childrearing practices (e.g., bowel training, weaning, parent-offspring sleeping arrangements, etc.) and later personality traits have failed to be confirmed (see Shweder 1979). It is an encouraging sign that some more recent theories conceive of human pre- and perinatal life as a period of autonomous adaptation which will manifest a normal developmental path in interaction with the environment, except under the most severe conditions (see Sameroff and Chandler 1975, Chisholm and Heath 1987, Tronick, Morelli and Winn 1987).
Suffice it to say, as ethnology becomes more interested in the cultural influences upon pre- and perinatal life, and as methods and insights open up the processes of learning at earlier and earlier stages of infancy and gestation, the concept of enculturation will have to change. Furthermore, something like the notion of neurognosis will have to be incorporated within the notion of enculturation in order to account for the roots of enculturation buried within innate patterns of neurophysiological structure, adaptation and development. It is apparent from the kinds of data reviewed above, as well as from other data available from such disciplines as ethology and developmental neurobiology, that knowledge at the level of perception and cognition is already present as a product of the inherent organization of the nervous system. The world of the fetus and neonate is "already there" in the sense that the world of perceptual experience (i.e., Husserl's "lifeworld") is a world (1) of bounded objects that can be recognized and differentiated into familiar and novel, (2) of socially significant objects and relations, (3) of motion and exploratory movement (however altricial), (4) of affective significance, (5) and probably of interesting and engaging dreams. The world is "already there" precisely because it is constituted within a conscious network by neural structures initially conforming to a heavy genetic loading, and then rapidly and selectively developing (within neurognostic constraints) in intimate interaction with the world. By implication, the earlier in life we examine the cognized environment, the more neurognostic we will discover to be its configuration. Likewise, the later in life we examine the cognized environment, the more enculturated and individually diverse we will discover it to be. Yet no matter how diverse the cognized environment appears to be, it is always possible to find the structural stamp of neurognosis in its organization and functioning (see Simon 1981).
The picture of enculturation emerging from a consideration of this view of pre- and perinatal psychology is one that can no longer conform to the common notion of a pre-cultural, tabula rasa-like and passive infant mind being somehow actively impressed by culture. Rather the picture becomes one of a developmentally autonomous, neurognostically precocious cognized environment in active and adaptive interaction with its operational environment, an interaction that produces developmental transformations in the structures mediating neurognosis and models that become ever more adaptively isomorphic with events in the operational environment.