Maternal supportiveness has a significant impact on the development of a child’s general intelligence and this effect may persist until late childhood, according to new research published in the journal Intelligence.
Previous research had shown that maternal supportiveness is positively associated with cognitive abilities in children, but the new study aimed to delve deeper into this relationship by addressing potential confounding factors and using a larger sample size. For example, it is possible that these associations could be explained by genetic factors or other variables.
The researchers also aimed to explore whether the effect of maternal supportiveness on general intelligence was specific to certain abilities or if it had a broader impact on overall intelligence.
“The Wilson effect (the increasing of heritability with age) indicates that early in life individual differences in general intelligence are largely due to the environment shared by people living in the same household, while in adulthood differences are largely due to genetics. It seemed reasonable to predict that one of these early environmental influences is maternal supportiveness,” explained study author Curtis Dunkel, an independent researcher and consultant.
The researchers examined data from families who participated in the Early Head Start Research and Evaluation Study (EHSRE) between 1996 and 2010. The final sample for analysis consisted of 1,075 children (529 girls and 546 boys). The racial/ethnic composition of the sample included 409 White children, 347 Black children, 241 Hispanic children, and 54 classified as “other.”
Maternal supportiveness was measured using a semi-structured play procedure called the 3-bag task at ages 14 months, 24 months, and 36 months. The task involved parents and children playing with toys in three bags, and their interactions were videotaped. Trained graduate students rated the interactions based on three aspects of maternal behavior: parental sensitivity, cognitive stimulation, and positive regard.
Cognitive ability was assessed at different ages (from 14 months to 10 years) using various measures, such as vocabulary production, vocabulary comprehension, early gestures, and mental development tests. These measures were factor analyzed to create a measure of general intelligence.
The study also considered other factors that could influence the results. Maternal cognitive ability was measured using a vocabulary test, and the child’s temperament was assessed using the Bayley Behavior Rating Scale.
Dunkel and his colleagues found that there was a positive association between maternal supportiveness and the child’s general intelligence. This means that when mothers were more supportive of their children, the children tended to have higher general intelligence scores. This association remained significant even after controlling for other factors such as the mother’s own intelligence.
The findings indicate “that maternal supportiveness influences general intelligence early in life,” Dunkel told PsyPost. “However, previous research clearly indicates that this effect is washed away by adulthood such that the lion’s share of differences in adults in intelligence is due to genetics. It remains a mystery why these early environmental effects appear to completely wash away. This means even though maternal supportiveness is important in the short term, in the long term it doesn’t matter how supportive your mother was.”
The researchers also found that children who are more interested and responsive to their parents’ efforts to stimulate their thinking may receive more encouragement from their mothers, which can contribute to higher general intelligence scores.
When they took into account the child’s temperament in their analysis, they noticed that the direct effect of maternal supportiveness on general intelligence became smaller. However, they still found that maternal supportiveness had an indirect influence on general intelligence through its impact on the child’s general intelligence at the age of four.
In other words, even though controlling for temperament weakened the direct link between maternal supportiveness and general intelligence, it didn’t eliminate the overall effect.
Dunkel said he was surprised to observe the “strong effect of maternal supportiveness on general intelligence,” which could be an area for future research. “Moms are most likely teaching specific abilities (e.g. reading), why would it impact general ability?”
But the study, like all research, includes some caveats.
“The children in the study were only followed until they were 10,” Dunkel said. “What would we find if maternal supportiveness and general intelligence were measured into early adulthood. As mentioned earlier, it appears as if the effect disappears. So, when exactly does it disappear and why?”
But the researcher noted that even a slight advantage in cognitive performance during critical stages of a child’s development can lead to significant outcomes.
“There is some research indicating that the effect lasts until early adulthood,” Dunkel explained. “This is an important age when having a slight edge in cognitive performance may be important (e.g., college admissions). Thus, while maternal supportiveness may not matter for general intelligence at age 40, it might be important in the course of an individual’s life.”
The study, “Maternal supportiveness is predictive of childhood general intelligence“, was authored by Curtis S. Dunkel, Dimitri van der Linden, and Tetsuya Kawamoto.