This was the issue taken up ten years earlier by one of the first widely recognized evolutionary psychologists, Robert Wright, when he wrote (Time 1995), “the suburbs have been particularly hard on women with young children. In the typical hunter / gatherer village, mothers could reconcile a home life with a work life fairly gracefully, and in a richly social context. When they gather food, their children stay either with them or with aunts, uncles, grandparents, cousins or life-long friends. When they are back at the village, childcare is a mostly public task – extensively social, even communal.” An isolated mother with bored small children is not a scene that has parallel in the hunter / gatherer existence of the Hadza.

It is not just the parents that feel this stress; children also need the experience of seeing both their parents’ working lives, and their private lives. Children need more realistic experiences of what matters to their parents than simply an hour of “quality time.” Children need – not simply want – the world that their pre-Industrial Revolution ancestors had when parents and children had common agendas. “As we attempt to progress as a society, we may unwittingly erode the building blocks that are the origins of our highest mental abilities”, warns Stanley Greenspan.

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It was Freud who noticed that between the ebullient learning and uninhibited play of the pre-pubescent child, and the querulous and impassioned search for independence of the adolescent, there was a period of apparent tranquility that he called the Latency Period. This was a time when both sexes appeared to have developed almost adult bodies, but their interests were still those of the younger child untroubled by sexual tension; a time when girls enjoyed the company of other girls, and boys relished the excitement of team games, camping trips and the enthusiastic pursuit of hobbies. It was a period, Freud suggested, when youngsters consolidated the emotional behaviours that had served them well as children in preparation for the radical shakeup of adolescence. “It was a time when they gathered physical and psychological strengths to explore the world, becoming confident learners and confident socially. They were marshalling their forces to be able to go into puberty”, wrote Dr Carr-Greg, an adolescence psychologist, in Melbourne early in 2004. It was a period which, when Freud was writing in the early twentieth century, was thought to last for several years.

Not so any longer. The average age at which puberty hits is now twelve or thirteen compared with sixteen just a few decades ago. There seem to be two reasons for this, one biological, and the other cultural. There is little doubt that significantly better supplies of food (not the same, necessarily, as a better diet) has speeded up the biological maturing process. Secondly cultural change in modern societies no longer requires teenagers to engage in hard physical labour to assist in supporting their families, and has been replaced by a vast media empire encouraging children, at ever younger and younger ages to assume the behaviour and attitudes earlier associated with young adults. “Consequently”, writes Carr-Gregg, “adolescence is now an extended period of vulnerability, starting much earlier and finishing much later than ever before.”

What we are now seeing is a short-circuiting of the latency period. “Today some young people merely dip their toes into the latency period before the combination of peer pressure, an unrelenting marketing machine, and their own physiology lures them into the kaleidoscope of adolescence.” Such youngsters behave as if they were several years older than they really are. “They haven’t completed the vital work of the latency period, and consequently don’t have the capacity to face, overcome or be strengthened by, adversity – something which was the common experience only a generation or so ago.” Adolescence, in the society we have recently created, has become more of a threat than a benefit, and adolescents are seen as a form of life most people want to avoid, rather invest in for their joint futures. It is vastly important, therefore, that all those concerned with young people rediscover what it is that this biological adaptation of adolescence is really all about, and to recognize that it is a once-and-for-all developmental opportunity.

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Given that, in many developed countries, there is much concern about the malfunctioning of secondary education, but a sense that primary education “generally knows what it is doing”, it must surely be significant that, in comparison to a wealth of recent research on the young brain, there is very little research indeed on the brain of the adolescent – and even less on how adolescents learn.

It was only in 1991 that Dr Jay Giedd started the first long-term, longitudinal study of the changes going on in the adolescent brain by using sequential functional MRI scans of some eighteen hundred youngsters over a number of years. This has led Giedd and others to challenge the earlier assumption by Swiss psychologist, Jean Piaget, that brain development is virtually complete by the age of twelve. Far from it, says Giedd as he studies his research, the teenage brain is far from finished, and indeed may not stabilize until the age of twenty. “Instead it remains a teaming ball of possibilities, raw material waiting to be synaptically shaped. The teenage brain is not only still incredibly interesting but appears to be still wildly exuberant and receptive.” Giedd’s work shows conclusively that the first phase of neural proliferation and pruning to be found in the brains of the very youngest children is followed by this second wave of proliferation and pruning that occurs with the onset of adolescence. This affects some of our highest functions, and continues until the late teens.

During the early stages of adolescence, many of the neuro-connections that had been carefully crafted through interactions between the child, its parents and teachers, during the first ten or twelve years of life, and which had earlier enabled such children to behave in perfectly predictable ways, are suddenly fractured. Quite literally what had once been firmly connected parts of the neural system seem mysteriously to have been torn asunder. Functional MRI scans show many of these dendrites literally floating amidst the white matter of the brain apparently looking to make new connections – the connections the adolescent will have to rationalize for itself, and which will replace the connections suggested earlier by their parents and teachers. As this starts to happen the adolescent becomes unpredictable, unreasonable, careless and probably carefree, constantly questioning and being outlandishly disrespectful of the social order that it had earlier, apparently eagerly, accepted. A pain in the butt we think; a stage when youngsters are best tightly corralled for their own safety.

Adolescents themselves see things very differently. In the words of a sixteen-year-old Romanian girl recently “(adolescence) is the age when you have certainties, when you know exactly what you want, who you are, who everyone else is. Life hasn’t destroyed your certainties yet. Being young means feeling omniscient, very strong, beautiful, invincible, undying… prudent and indifference are words that you cannot bare… you never again have this courage, that of risking everything in one second. It will never again seem so normal to make mistakes as it seems now when you have the excuse that you are looking for truth.”

Such over confidence, such arrogance, are hard to accept for an older generation that knows that it has long-since compromised such ideas. No wonder, from an evolutionary perspective, in times past whenever our ancestors had difficult challenges to face for which they had no personal stomach, they would happily turn to adolescents to be their soldiers, merchants, navigators, explorers and colonizers. Society, going back to the stage of the diaspora out of Africa, needs both the impatience, and the energy, of adolescents to keep it vital. As with today’s young people so it was with our ancestors who had to master the skills passed to them by their parent’s generation before they could start to make intelligent adjustments of their own to each new set of circumstances.