Discussion

For personal use. Only reproduce with permission from The Lancet Publishing Group. Sometimes a good idea is just too obvious. In one of my books about the evolution of the mind, I slipped in a few pages about feral children—amazing stories of kids brought up like animals. Such is the amount of mail I still get about the subject that I’ve always kicked myself for not turning it into a whole book. An easy seller was right under my nose. But the other day I was briefing the producer of a forthcoming Discovery channel program on feral children and I remembered why, in the end, their fascinating tales lead nowhere in particular.

Throughout history, feral children have seemed able to answer one of the biggest questions about the human brain—what makes it different from that of an animal? Is human consciousness innate, or is it the product of language and socialisation?

Several kings, including James IV, were said to have locked away children at birth to discover what would happen. Then there were the celebrated cases like Peter of Hanover who were found roaming the forests and brought into society for civilising. But the real jaw- dropper story is that of Amala and Kamala, two girls reared by a pack of Indian wolves.

Villagers near Midnapore in the Bengal jungle in the 1920s told tales of frightening spirits running with the wolves at night. The Reverend Joseph Singh, a missionary, eventually traced the spirits to a wolf lair and dug out two girls aged around three and five.

The girls had been snatched as babies while their mothers worked the fields. Probably taken to feed the cubs, the wolf mother “warmed by the chemistry of maternal hormones” may then have treated the helpless, snuffling infants as her own.

Singh described the girls’ appearance as hunched and hideous. Their hair was matted. They scampered on all fours.

There was no trace of humanness in the way they acted or thought. They tore off clothes and only ate raw meat. They never smiled or showed interest in human company. The sole emotion that crossed their faces was fear. They did not even seem able to hear human voices. Yet their senses were wolf- sharp. Singh said they could see in the dark and smell a lump of meat across a 3 acre yard.

Singh did his best to rehabilitate his charges. He was puzzled that the girls seemed so unhuman, with no power ofspeech, warmth, or self-regard. But he reasoned that the learning of wolf habits had somehow blocked the free expression of their innate human characteristics. Once they had had a chance to loosen their tongues, they ought to become like normal children and would even recount the tale of their terrible years as wolf cubs.

Sadly the younger child, Amala, soon sickened and died.

The older, Kamala, became somewhat housetrained yet never learnt to speak. Eventually Kamala could manage about 40 stilted words, but no sentences or conversation. And her mind remained on the level of an animal’s with no apparent spark of insight or self-awareness. The unlearning of wolf habits did not release the Christian soul that Singh had expected to find.

It had seemed like the perfect “experiment”. Children reared by animals and then brought back into civilisation. If the human mind was innate, then the girls should have been found like Mowgli and Tarzan—speaking, intelligent, mentally complete. But if the human mind was really an animal mind transformed by language and socialisation, then the girls would grow human only after their return to the fold.

However, as I told the crest- fallen producer, neither happened.

As we now know, the brain has critical periods for learning language and other mental skills.

The story is much more complicated than the old nature–nurture, blank slate versus genetic module, dichotomy allows. It is really a three-way evolutionary story in which there is an evolution of the brain’s circuitry through experience and synaptic-pruning, coupled to the influence exerted by biological evolution through the genes and cultural evolution through memes. So three kinds of adaptive history get interwoven and no single experiment or simple slogan can unravel the intricate processes that forge a human brain.

The poignant story of the wolf girls suggests that culture and speech are essential for the shaping of the human mind.

But equally well, it could be that the lack of a social trigger at the right moment meant that certain genetic programs failed to kick in. The harsh fact of critical periods simply makes it impossible to decide on the evidence available. Perhaps I missed a trick. But this was why Amala and Kamala ended up a footnote in a much more complex book.

Feral children John McCrone http://www.btinternet.com/~neuronaut/ THE LANCETNeurology Vol 2 February 2003 http://neurology.thelancet.com 132 The last word