Two groups of children receiving different levels of hygiene and nutrition and different levels of loving care. The ones being loved fared much better.
Anne Harrington is a Harvard College Professor and Professor for the History of Science, specializing in the history of psychiatry, neuroscience, and the other mind and behavioral sciences. In her book, “The Cure Within – A History of Mind-Body Medicine”, she shares a 1945 study (on page 191) by psychoanalytic psychiatrist Rene Spitz in which one group of babies was cared for with good hygiene and excellent physical care but received little if any individual love or attention. This group became physically and emotionally stunted. Most could not walk or talk even at the age of four. “Within two years 37 percent … had died from infection.”
In contrast, a second group of babies was cared for in a prison nursery that was “far dirtier” but received loving affection from their mothers each day. “Not a single one of the second group of children succumbed to infection during the five-year period of Spitz’s study.”