Not nature, not nurture – impulsive small fry say it's both

Among policymakers, human service professionals of every stripe, and even among supposedly objective researchers, the idea that genes can be the cause of psychological, behavioral or emotional problems is sacrilegious.

So it’s OK to talk about inheriting your green eyes from your mother. But not quite yet your bad behavior. Conventional wisdom says that has to come from her poor parenting rather than from her genes.

Some might concede that genes play a part in the origins of problems, but they will quickly turn the conversation toward how life experiences shape individuals. This tendency undoubtedly reflects a firm belief in the value of social benevolence – in the possibility of improving the lot of troubled children and adults by improving their experiences.

However, recent advances in genetic research are making it harder to ignore the influence of genes. A quick swipe of the inside of the mouth yields a wealth of genetic information. For example, researchers have discovered that a certain component of our genetic make-up (known as an 'allele') is associated with aspects of attention-deficit/hyperactivity disorder (ADHD).

Brad E. Sheese and his colleagues at the University of Oregon have been looking at the influence of this allele in a group of children aged 18-21 months. They found that 14 of the 48 had the allele in question; but they also found that having it didn’t necessarily translate into behavior problems. Instead, the allele plus poor parenting (as observed by researchers in a laboratory) tended to result in “sensation seeking” (defined as impulsivity and an affinity for risky behaviors). Children lacking the allele, by contrast, were not influenced by parenting quality.

These results should certainly appeal to the optimistic policymaker or practitioner. Rather than suggesting that children are fated to their problems by their genes, the findings suggest that certain children are more influenced by their environments because of their genetic makeup. And if we can identify these impressionable children, we might help them to avoid potential problems. [See also: A pair of genes to suit every occasion? [1]]

• Summary of “Parenting quality interacts with genetic variation in dopamine receptor D4 to influence temperament in early childhood” by Brad E. Sheese, Pascale M. Voelker, Mary K. Rothbart, and Michael I. Posner in Development and Psychopathology, Volume 19, Issue 4 (2007), pp1039–1046.

• first published in Prevention Research on December 4th 2007