Children resemble their biological parents, inheriting physical characteristics such as hair and eye color, body shape and skin pigmentation. But what about personality traits?
Avshalom Caspi and Terrie Moffitt, husband and wife researchers at Duke University, are working on an answer.
The clinical psychologists have been teasing apart nature vs. nurture for more than 20 years, and their research has garnered several awards, most recently the Klaus J. Jacobs Research Prize for Productive Youth Development. The couple received the prize, which includes about $1million, earlier this month in Zurich.
So far, their best conclusion in the long-running nature/nurture debate: It depends.
"It's probably the best statement you can make," Moffitt said in a phone call from Israel, where the couple are on sabbatical. "The research shows how much everybody is an individual. That's bad news for scientists, because it's hard to make broad generalizations."
Still, Moffitt and Caspi keep looking for similarities among participants in two large, long-term studies - 1,000 New Zealanders born in 1972 and 1,100 British families with twins born in 1994 and 1995.
The Dunedin Longitudinal Study and the Environmental-Risk Longitudinal Twin Study have provided researchers years worth of psychological, environmental and genetic test results. The information could reveal genetic markers that predict mood disorders such as depression, antisocial and criminal behavior, psychosis and addiction.
Caspi is better at data analysis, Moffitt said. Her expertise is in collecting the data and interpreting it for health care policy makers, which is where their research gets real.
It turns out, for example, that depression, substance abuse and domestic violence are root causes of childhood hunger in poor families. Depressed, addicted and abused mothers are so disorganized they are unable to manage the food budget, Moffitt said. When social workers get the mothers treatment, the family food situation improves.
In the past three years, Moffitt and Caspi have published study results on the links between childhood conduct problems and early exposure to drugs or bullying; how breast feeding affects a child's IQ; and pre-adolescent signs of psychotic disorders.
