This may provoke recognition in many parents: a researcher into OCD (obsessive-compulsive disorder) was looking for the involvement of a neurotransmitter; he came up empty in his search, but in a what-the-hell spirit he sent off his samples to be analyzed for less well-known chemicals -- and found to his astonishment that sufferers of OCD were showing very high levels of oxytocin, the famous "pair-bonding" hormone. On reflection, however, he realized that the behavior of new or expectant parents often resembled OCD, and if you think about it, people "in love" are of course famous for obsessive behavior. So he's suggesting that OCD is a dysfunctional variant of something that is in fact adaptive and normal.

And more on the neurology of deceit -- a recent study has found distinct structural differences in the brains of pathological liars, confirming previous research indicating the prefrontal cortex is crucially involved in lying, and suggesting an important difference in white and grey matter. The findings suggest pathological liars have two things going for them: a greater verbal talent, and a reduced ability to make moral decisions -- reflections of a surplus of white matter and a proportionate deficit in grey matter in this brain region. Interestingly, other studies of autistic children (who have trouble lying) show the opposite pattern of gray matter/white matter ratios.