Nature-Nurture Redux

In 1690 John Locke proposed that humans start with a tabula rasa and acquire most all of their behavioral traits from environmental experiences, thus denying the influence of heredity.  

This nature-nurture controversy is again in the news with a recent study that shows poor children have smaller brains than affluent children.  Neuroscientists studied the region of the brain that handles language, memory, spatial skills and reasoning and discovered that the brains of children in families that earned less than $25,000 a year were smaller than those whose families earned $150,000 or more. The children with smaller brains scored lower on a battery of cognitive tests.  The purpose of the research was to better understand the academic achievement gap between poor and more affluent children. While the new research does not explain the reason for brain differences, the researchers have postulated two theories: (a) brain size may related to poor nutrition and lower-quality health care, or (b) poor families tend to live more chaotic lives, and that stress could inhibit healthy brain development. There is now a study to investigate whether giving low-income mothers a small or large monthly sum of cash impacts the cognitive development of their children in the first three years of life. On the other hand, James Thompson, a psychologist at University College London believes that there is a genetic component that should not be overlooked.  His point is that basically less ability people marry other people with less ability and have children which on average have less ability.  To be sure all children are capable of learning regardless of their backgrounds or economic situation.  Steven Pinker famously emphasized in his best-seller that the behaviorist’s position is rooted in the ideology espoused by John Locke that humans are conditioned by culture because social influences can be used to educe desirable traits or repress undesirable traits. The pile of evidence to the contrary including this recent brain size study are an inconvenient truth.