Individuals who experience sensitive caregiving during the first three years of life may see lasting effects on their relationships and academic achievement, research published Thursday in the journal Child Development suggests.

The question of whether caregivers’ behavior can impact these aspects of their children’s lives spans even before Sigmud Freud’s psychological study of parent-child relationships in the 1800s. However, research has yet to analyze this potential association in adulthood, said lead study author Lee Raby, a postdoctoral researcher at the University of Delaware.

“There were two unanswered questions: The first is, ‘Does the quality of care that one receives in early life affect childhood, but does it also have long-term predictive effects for functioning into adulthood?’” Raby told FoxNews.com.  “The second question is,  ‘Do the predictive effects of early caregiving experiences decrease in time as children grow older and are faced with new challenges and experiences?’”

Raby and his co-authors— researchers at the University of Minnesota, the University of Delaware, and the University of Illinois at Urbana-Champaign— expanded upon a previous study, the National Institute of Child Health and Human Development (NIHD) Study of Early Child Care and Youth Development, which suggested that sensitive caregiving in early childhood has an enduring effect on academic and social domains through adolescence.

In the new research, scientists studied about 240 people for their first 32 years of life to examine whether that link existed through adulthood.  They noted that the impact of sensitive caregiving had a lasting effect on a child’s social competence and academic performance past age 30, and that this impact was most pronounced in the academic domain.

In 1975, at the onset of the study, mothers were recruited during pregnancy through a previous, unrelated short-term research called the Minnesota Longitudinal Study of Risk and Adaptation, which was meant to identify factors that predicted maltreatment. One of the known risk factors for maltreatment is poverty, so all of the study participants for that study— as well as the current research— were below the poverty line in Minnesota.

For the current study, researchers observed the mothers’ interactions with their children on four different occasions: at three months, six months, two years, and three and a half years into the study. At the three- and six-month marks, researchers used a seven-point scale to assess sensitivity and a nine-point scale at the two- and three-year marks.

Researchers defined sensitive caregiving as the general manner of interacting and caring for a child, which was distinct from parenting practices such as spanking.

Parents who are highly sensitive in their interactions “tend to respond to the child’s initiatives and cues and signals contingently and promptly, and when they’re involved in the interactions with the child, they’re warm and there’s a lot of positive emotion,” Raby said.

Besides assessing caregiving sensitivity, researchers took maternal education and occupation into account. “In order for us to determine whether any long-term effects of caregiving were attributable to caregiving and not socioeconomic status, we included those as variables and not as controls,” Raby noted.

Study authors observed the caregivers’ interactions with their children through age 19 by filming them in a controlled setting. They saw participants at least yearly until age 9, and then periodically until age 19. During grade school, researchers assessed the children’s academic performance by giving them math, reading and writing tests, and they assessed their social competence by surveying their teachers with the caregivers’ permission.

When the child participants passed age 19, researchers assessed their social competence by surveying them periodically in person or on the phone. At age 23, researchers asked about their dating experience, and by age 32, researchers asked whether participants had taken steps toward or achieved a serious relationship. Study authors assessed their academic performance about every two years by asking about their progression in higher education.

On average, Raby said, children who received less sensitive caregiving were at a greater risk of performing poorly on academic tests and were more likely to drop out of school during adolescence.

“That’s the glass-half-empty way of looking at it,” Raby said. “The reverse is also true: Individuals who received the most care were doing on average better on the academic tests and were more likely to go to college and graduate, and sometimes get postgraduate degrees.”

But, most surprising to the study authors, sensitive caregiving was more strongly associated with academic performance than social competence.

“This is not the first time that we, the field, has observed that this early sensitivity effect is more associated with academic than social performance, but much of the theory that is driving this area of research would anticipate the reverse of that,” Raby said. “It creates questions.”

Raby pointed out that the results suggest a link between early sensitive caregiving and these domains, but further study is needed to determine whether a cause-effect relationship exists.

Because the child study participants are now in their 30s, next, researchers plan to study how their sensitive caregiving during childhood may have an impact on how they interact with their own children.

“Mental health is also important,” Raby said. “And then a new direction of the study is going to the origins of physical health problems. We know that stress is not good for health, and that stress early in life in the form of not-optimal parent-child relationship may have these kinds of long-term effects on biological health. Those are all unanswered questions.”