"Most parents know that when they interact with their infant and young toddler, they are laying important foundations for the child's future development," lead study author Grazyna Kochanska of the University of Iowa said in a statement. "Now we have a better understanding of what that really means. Your investment in building a mutually responsive, positive, close relationship early on will generate considerable payoff several years later."

The researchers observed parent-child ties in 102, mostly white, volunteer families from the time the child was 7 months to age 2. When the child was 4 years, and 4 months old the researchers "tested" the children.

The findings, published in Child Development, showed the 4-year-olds with close parental ties responded to their mothers' requests not to do something more than children who without these ties. The children with close ties also did a better job regulating their own behavior -- such as holding candy without eating it, the study said.

Results with fathers were much the same, but the researchers say more research is needed to better understand the dynamics of the father-child relationship.