READING Colin Turnbull's latest book, 2 The Human Cycle, is like biting into a chocolate bar and discovering it's carob. Even if you like carob, you can't help being disappointed. It's not what you expected.

The Human Cycle pretends to be a cross- cultural study: how people go about the disorienting business of growing up--in Africa, India, Tibet, and England, all of which are described with a detachment that makes them equally exotic. The six chapters--on childhood, adolescence, youth, adulthood, old age, and life as a whole-- are presented as stages leading toward a goal, although what the goal is Turnbull never makes clear. Presumably, death. Or, perhaps, a good death.

In balancing the cultures, however, Turnbull thumbs the scale. His detachment is not scientific; it seems more the result of his being shellshocked by his own past. He is quick to damn his own culture and redeem another, even when the similarities outweigh the differences. He respects the Hindu student's custom of carrying a staff but not the Westminster student's custom of carrying an umbrella-- even though both have symbolic value within each culture. He is--properly--appalled by the birching English school boys traditionally suffered, but not by the thorn-switch beatings given to Mbuti boys.

According to Turnbull, in other cultures the stages of life are steps that people ascend; but in our culture the stages are an escalator: you don't climb from immaturity to maturity, you get stuck on one of the bottom steps-- say, adolescence--and are carried on that step into an adolescent old age.

The trouble with what Turnbull seems to be doing is that he is trying to compare incomparables. He is balancing generalities about other cultures against a specific life--his own --in Western culture. He is comparing the social ideal with the social real, comparing what is supposed to be with what is. And that doesn't work.

The reader cannot trust his description of how ecstatic Mbuti youths are when they discover sex, not just because that is a generality, but because ecstasy cannot be quantified. How does Turnbull judge the ecstasy of the Mbuti youths, even any particular Mbuti youth? How do you verify another's feelings. Observation can mislead. If one's culture expects one to act ecstatically, one may go through the forms and seem ecstatic, even believe one is being ecstatic, but short of defining brain- wave patterns associated with ecstasy and comparing those with the patterns of a Mbuti youth discovering sex (obviously an experiment that would run into certain design problems) there is no way to speak with authority about someone else's emotions. And although Turnbull discusses behavior, he returns over and over to feelings. How does it feel to grow up in one culture compared with another? Does one feel secure or alienated? Content or discontent? Peaceful or anxious?

Turnbull's method also fails because, even if he were able to compare the feelings of specific individuals in other cultures with his own, the reader cannot trust that Turnbull's experience and feelings are typical of his culture. And this is where the chocolate becomes carob.

The book is really not a cross-cultural study. Nor is it an autobiography or a memoir. It is a mediation on his own life, and, because Turnbull is an anthropologist he slips into using the tools of his profession. He is not comparing Western culture with other cultures. He is trying to make sense of his own life, testing his experience against the ideal experiences of other cultures. He presents the material in the form of a cross-cultural study because that is how he has been trained to approach the world. But the trappings of anthropology are, in some ways, irrelevant to what he is doing.

The anthropology is important for its dramatic effect only. The book is the story of a man so hurt by his life, especially by his childhood, that he cannot talk about it without wincing. Anthropology is the way he winces. When the book is read with that understanding, the sections discussing other cultures move the reader not because of their content (their content is not the point), but because they show a mind trying to escape into the belief that childhood and adolescence need not be painful. Africa, India, and Tibet are not countries in the real world; they are precincts of Never-neverland.

Midway through the book, Turnbull says:

"We miss much of the very real and deeper social significance of a great deal of what goes on around us daily by taking it at face value."

If the reader takes this book at face value, he or she will miss its significance. If the reader can penetrate the book's disguise, he or she will find a story that, although painful to read, is touching and brave.