Poor Parents Matter More

I've been advocating for an accurate depiction of parenting for quite a while now. I've mostly focused on how parents have less influence than they think and that there are many practical reasons to have kids. However, I certainly admit I see problems caused by bad parenting my classroom all the time. So which is it, does parenting really matter that much or not? Well that depends on how wealthy you are:

For a paper in Psychological Science, researchers at the University of Texas at Austin and the University of Virginia looked at 750 pairs of American twins who were given a test of mental ability at the age of 10 months and then again at the age of 2. By studying the performance of identical versus fraternal twins, the scientists could tease out the relative importance of factors such as genetics and the home environment. Because the infants came from households across the socioeconomic spectrum, it also was possible to see how wealth influenced test scores.

When it came to the mental ability of 10-month-olds, the home environment was the key variable, across every socioeconomic class. But results for the 2-year-olds were dramatically different. In children from poorer households, the choices of parents still mattered. In fact, the researchers estimated that the home environment accounted for approximately 80% of the individual variance in mental ability among poor 2-year-olds. The effect of genetics was negligible.

The opposite pattern appeared in 2-year-olds from wealthy households. For these kids, genetics primarily determined performance, accounting for nearly 50% of all variation in mental ability. (The scientists made this conclusion based on the fact that identical twins performed much more similarly than fraternal twins.) The home environment was a distant second. For parents, the correlation appears to be clear: As wealth increases, the choices of adults play a much smaller role in determining the mental ability of their children.

There are diminishing returns to good parenting. If kids are already playing musical instruments, having intelligent conversations, and taking improv classes, the extra effort has minimal effects. Pretty good argument for some kind of universal early intervention.