Why do children always know when we want them to behave beautifully and do the opposite? No doubt Lady Cockburn thought it a delightful idea to pose as Cornelia with her children in the classical style so fashionable in 1773. Sir Joshua Reynolds has caught a moment of formal harmony just before it dissolves into all too human chaos. Who can doubt that at any second George, the imp on the right of the picture, will tighten that chubby clasp into a strangle-hold and pull down the temptingly loose coils of mother's hair? James, the child on the left, will not be slow to join in and baby William will howl as he is trampled on by his lively brothers. One small boy on his own is (sometimes) manageable; three together in any century spell trouble for grown-ups! Their mother already has a faintly strained look behind her lofty pose. She is distancing herself from the situation by fixing her eyes on the middle distance in a way well known to those who have discovered from experience that pleas, bribes, prayers and even threats cannot prevail against the exuberant life in a group of children. Will she eventually give way with good humour and indulge in a romp, or will it be smacks and tears all round and nursemaids summoned to remove the guilty parties, roaring, back to the nursery? She looks quite young in spite of the stuffy pose so who knows which way it will go. We tend to assume that youngsters in the old days were always brought up with harsh discipline. Of course life was hard and brutal for everyone and child abuse common, but many parents have also loved, petted and delighted in their children throughout the ages. The stem puritanical manuals that grate on us so much – “You must break a child's will by the age of five”, “Spare the rod and spoil the child”, “Rule by fear” – were written by disapproving experts to counteract what were seen as lax tendencies to over-fondness and spoiling of children.