Source: Children. [In: Mortals and Others, v.1]

(... This is when his parents are untouched by modern child psychology, as the great majority still are. When parents have learnt the new catchwords, the only result is that the situation is reversed; it is now the parent who must suffer in silence while the child is allowed to make himself a nuisance. The modern parent is conscientious, but is not on that account any more instinctively fond of her child than the old-fashioned parent who finds relief for irritation in physical chastisement. Nevertheless, both struggle on, because sentimentality has decreed that there is no joy equal to that to be derived from the companionship between children and parents.
 This trouble is caused by failure to recognise a very simple fact, namely, that, at all ages beyond the second birthday, people prefer the society of their contemporaries to that of people much older or younger than themselves. ... The causes of this are physiological; children need constant movement and almost constant noise, whereas adults need rest for muscles and nerves.)