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Families and how to survive them - Robin Skynner & John Cleese:

John: I've read that normal babies are programmed to smile at the mother's face from very early on, before they can have any idea what they're smiling at, and that the baby's smiling engages the mother's feelings so she enjoys and loves the baby more.

Robin: Correct. An abnormal baby may fail to switch on the mother, so her maternal instincts don't get the go-ahead. Then she has to do everything from her head, from books, whether she wants to or not.

John: So the problem can be on either side?

Robin: Yes. Some experts think it's always the baby, but all the evidence I've seen suggests that there's a range, from one extreme where the parents do seem to be very cut off from their feelings, to the other where it's very hard to understand how they could have ended up with such a turned-out, abnormal child.