+ Book: The Evolution of Childhood

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Melvin Konner has published “The Evolution of Childhood: Relationships, Emotion, Mind,” (Harvard University Press).

It has been thought that children’s play, including the testosterone-driven adolescent variants, may have played a part in the development of civilisations.  Michelle Pridmore-Brown’s book review  in the Times Literary Supplement says

Since play is costly in terms of energy expenditure, and it is risky, it must have conferred survival and reproductive advantages.

All mammals play, Pridmore-Brown says, but none play the intricately constructed sorts of games humans do; they don’t have such complex emotional connections to their play; and no other species continues to play into adulthood.

Konner is a professor of neurobiology and anthropology at Emory University.  He has spent a lifetime studying the biological evolution of behavior and its cultural manifestations.

This ambitious book surveys human childhood from three vantage points: an evolutionary and cross-species perspective, that of genes, hormones and brain development, and also from perspectives considering social and cultural issues.

 Konner considers three stages of childhood.

First Stage

The first is birth; and human babies are strikingly immature compared to normative ape development.  Infants ought to be born at eleven months, but they would be so big they would break their mothers’ hips.

Nine  months in the womb is an evolutionary compromise: a standoff between big brains and bipedalism.  Human infants continue fetal growth through their first year.

This makes their survival chances fragile.  So it has been suggested that a reason babies are asocial for the first month is to make it   easier for mothers to postpone attachment.  Ape mothers bond immediately, unconditionally.

By three months, babies are exquisitely in control, using their helplessness as a front.  They are able to manipulate the behavior of the mother/caregiver using a kind of hormonal glue: holding an infant has opiate-like effects, even on men.  

According to Konner, the tripling of the size of the whites of human eyes — since the time of our ape ancestors — accounts for the power of the human gaze.   Infants are able to engage their helpers via a mixture of gaze, smiling and vocalization.

In its first half-year, the infant is indiscriminate with its affections.  But in the second half, it consolidates its attachments, hones its play repertoire, and experiences “stranger anxiety” as a result of limbic circuitry growth.  As this circuitry comes online, the infant needs other minds to develop normally.  If a child is deprived of social contact at this critical stage, it will likely be unable to form emotional attachments later on.

Humans wean their infants radically earlier than Great Apes, and this increases language proficiency and more sophisticated forms of play.  “Needless to say, language is crucial for increasing cognitive and social complexity in general,” writes Pridmore-Brown.

 Second Stage

The human child’s years between six and eleven are a dramatic structural alteration to standard Ape maturation.  Chimps go straight from weaning into puberty.

Homo sapiens experience a long hormonally quiescent “middle” stage before adolescence, keeping sex hormones at bay for several years in order to allow learning.  The evidence suggests that children with longer middle childhoods had an edge over those who did not.

The start of this period can be identified at eruption of the first molar.  In cognitive terms, this “5-to-7 shift” is known as the moment of “school readiness” in the industrialized world.

Instead of brain circuits coming visibly online as in the first period of growth, neural consolidation occurs.  This permits “metacognition” (thinking about thinking), which enables self-talk or interior speech. 

The ability to shift perspective makes for greater variability in play.  As children begin engineering their own games, they are in a sense directing their own brain assembly.  According to Pridmore-Brown

play serves to control emotion, to test limits and measure oneself against others, to acquire spatial skills and indeed culturally valued competencies that will later attract mates.

Play at this age also tends to solidify cultural group identity, an “us” in contradistinction to “them.”

These in-groups and out-groups trouble all playgrounds.  Konner believes these difficulties can be short-circuited through training.

Third Stage

However, with the onset of adolescence this finely enculturated, mostly moral, well-equipped being is assaulted by hormones . 

Testosterone and — in the case of girls, estradiol –transform white and gray brain matter ratios.  This amplifies some brain regions, shrinks others, and leads to sexual behavior, aggression and risk-taking.  After further hormonal surges, brain maturation usually enables adult levels of inhibition and reason.

Susceptibility to peer influence is highly variable, but generally peaks at around the age of fourteen.  Aggression has a remarkably stong genetic component, but can be modulated by environment.  In cultures where adolescents undergo ritualized puberty initiations, this aggression can be channeled; in contexts like our own, “the transition to adulthood is messier.”

The vast majority of children emerge unscathed, although one study estimates that approximately 11 per cent of adolescents have chronic difficulties.

At this age, a child may become idealistic or turn to religion. These young people may choose self-imposed rigid rules of conduct, gaining a bulwark against entropy and anxiety.

If average behavior typically follows a set pattern between birth and five, and between six and eleven, this is no longer the case in adolescence.   Cultural context matters a lot, as does individual biology.

The fact is that hormonal surges that increase risk-taking enable new levels of cognition.  Play takes on a new form, potentially more rebellious but also potentially creative, in the case of young computer tinkerers.

Pridmore-Brown calls Konner a compassionate Darwinist.  He insists on understanding, rather than judgement.  Knowledge of our evolutionary legacy affords us the knowledge that enables better interventions.

sole source for this post is Michelle Pridmore-Brown’s article in the October 1, 2010 issue of the Times Literary Supplement.  Melvin Konner’s “The Evolution of Childhood: Relationships, emotion, mind”is published by Harvard University Press, $39.95.  ISBN 978-0-674-04566-8.

tutoring in Columbus OH:  Adrienne Edwards  614-579-6021  or email  aedwardstutor@columbus.rr.com


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