In recent years, for example, there has been much interest in the idea that one of the most fundamental factors in explaining personality is birth order: older siblings are domineering and conservative, younger siblings more creative and rebellious. When psychologists actually try to verify this claim, however, their answers sound like the Hartshorne and May conclusions. We do reflect the influences of birth order but, as the psychologist Judith Harris points out in The Nurture Assumption, only around our families.
