Disney movies are rife with evil stepmothers who torture poor innocents such as Cinderella and Snow White. (Stepfathers somehow get off the hook.) But in times of plenty, stepparents do not treat stepchildren any worse than their own, according to a new study co-authored by Kai Willfuhr of the Max Planck Institute for Demographic Research and Alain Gagnon at the University of Montreal.
The pair of scholars reached the conclusion after analyzing the mortality of children raised in blended families in the 17th to 19th centuries. They compared the Krummhorn region of present-day Germany, which was densely populated, with growing Canadian settlements in Quebec. For both areas, they calculated whether the children's chances of survival changed when a stepmother moved in.
They found that in Krummhorn, where opportunities for demographic growth were scarce, children from a father's first marriage were much more likely to die before age 15 if a stepmother moved in. But in Quebec, the arrival of a stepmother barely changed a child's risk of dying young.
The finding challenges what evolutionary psychologists call the "Cinderella effect": the theory that stepparents view stepkids as competitors to their own – and proceed to neglect or abuse them.
"We are now able to prove that the Cinderella effect is not an inevitable reflex of stepparents," Willfuhr said. "The stepmothers in Quebec seemed to understand that the offspring from their husband's first marriage were not competition for their own children with their new husband."
Gagnon noted that Quebecois families of the era were huge, and intent on populating empty land. "More hands meant greater food security or even wealth," he said, adding that "children from a previous marriage could often help the stepparent care and educate their younger brothers and sisters."
In the great stepparent debate, of course, there is research to back up either side. An Australian study published in 2005 found that stepchildren under age 5 were at significantly increased risk of fatal accidents (drowning in particular) than children with intact biological families.
The jury is still out on how evil stepparents truly are. Still, it's worth considering that when it comes to the "Cinderella effect," context may be everything.