Breastfeeding may give babies early practice in self-control, longitudinal study suggests

A recent study published in the journal Appetite suggests that infants who are breastfed may develop better self-control skills by the time they reach preschool. The findings provide evidence that the act of breastfeeding gives babies early, regular practice at recognizing when they are full. This daily practice tends to improve their ability to manage their impulses and behaviors later in childhood.

Scientists designed the study to explore how early life experiences shape a psychological concept known as executive function. Executive function refers to the underlying mental processes that help people manage their thoughts, actions, and emotions to achieve specific goals. These mental skills undergo major development between the ages of three and five years.

One specific component of executive function is inhibitory control. This is the ability to stop an automatic or impulsive response to a situation. Instead of acting on immediate urges, a person with strong inhibitory control can pause and choose a more appropriate action.

“For more than 30 years, our research has focused on children’s self-regulation development, their growing ability to manage their thoughts, emotions, and behavior,” said study author Sophie Jacques, an associate professor in the Department of Psychology and Neuroscience at Dalhousie University.

People with strong inhibitory control tend to have better health and financial outcomes in adult life. “Because self-regulation is so important across the lifespan, many researchers (including us) are working to identify the early factors that may help foster these skills during development,” Jacques noted.

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Research shows that babies who are breastfed have a lower risk of becoming obese as they grow up. Some scientists propose that this happens because breastfeeding acts as natural training for appetite regulation. This theory suggests that nursing teaches an infant how to consume only the amount of energy their body actually needs.

When feeding an infant from a bottle, parents can see exactly how much milk is left in the container. Because of this visual cue, parents might accidentally coax the baby to finish the bottle even after the infant is full. “This can lead infants to rely on external cues, such as an empty bottle, rather than their own sense of fullness,” Jacques explained.

When feeding directly from the breast, the mother cannot see the exact volume of milk the baby consumes. As a result, breastfed babies are allowed to rely on their own internal feelings of fullness to know when to stop eating.

“Beyond appetite regulation, we wondered whether breastfeeding might also provide broader ‘on-the-job training’ for self-regulation skills,” Jacques said. “Controlling their food intake multiple times per day may help infants practice self-control more generally.”

To test this idea, the researchers analyzed data from the Québec Longitudinal Study of Child Development. This long-term project tracked a large, representative group of children from infancy through childhood.

“Because the children in that study were born before breast pumps were widely used, they offered a unique opportunity to explore how breastfeeding history relates to the development of children’s self-regulation,” Jacques noted.

The initial sample included 572 infants. When the babies were five months old, and again at seventeen months of age, mothers reported whether they were breastfeeding and for how long they had done so.

Using this information, the scientists divided the infants into four specific groups. These groups included babies who were never breastfed, those breastfed for less than three months, those breastfed for three to six months, and those breastfed for six months or longer.

When the children reached three and a half years of age, researchers visited their homes to evaluate their cognitive skills. By this time, 491 children remained in the study to complete the behavioral tests.

The children completed several direct assessments of their executive function. One test was Luria’s Hand Game, which is specifically designed to measure inhibitory control.

In this game, an adult shows the child a hand gesture, such as making a fist or holding out a flat hand. The child is instructed to do the exact opposite of what the adult does. This forces the child to suppress their automatic urge to simply copy the adult.

Another test of inhibitory control involved a verbal task using pictures of the sun and the moon. Children were shown a picture of a sun and told to say the word night. When shown a moon, they had to say the word day.

Mothers also filled out questionnaires about their children’s daily behavior. They rated how often their child showed specific signs of hyperactivity and inattention over the previous six months.

The researchers included several control variables in their statistical models to ensure their findings were as accurate as possible. They accounted for the family’s income, the mother’s education level, smoking and alcohol use during pregnancy, and the mother’s weight gain before birth. They also factored in the child’s birth weight, gestational age, and general intelligence scores at age three.

The analysis revealed that breastfeeding duration predicted better inhibitory control at three and a half years of age. Infants who were breastfed for at least three to six months performed better on Luria’s Hand Game than infants who were never breastfed.

These children also showed fewer hyperactive and inattentive behaviors in their daily lives, according to their mothers’ reports. For example, mothers of breastfed children were less likely to report that their child fidgets, is impulsive, or has poor concentration. The behavioral benefits were most apparent for infants breastfed for more than six months.

Interestingly, breastfeeding only predicted inhibitory control. It did not predict other executive function skills, such as working memory or cognitive flexibility. Working memory involves holding information in your mind and updating it as you solve a problem. Cognitive flexibility is the ability to shift your thinking and look at a situation from a different perspective.

The lack of a link to these other skills supports the authors’ theory that breastfeeding specifically trains self-restraint. It suggests that nursing does not simply boost overall brainpower, but rather provides targeted practice in behavioral control.

While the study provides interesting insights, there are some potential misinterpretations and limitations to keep in mind. The research team stressed that their findings do not imply causality.

“Although we found a clear association between breastfeeding and children’s inhibitory control, it is important to emphasize that this study was correlational. This means we cannot conclude that breastfeeding directly caused the improvements in self-regulation,” Jacques explained. “It is also possible that the relationship works in the opposite direction. For example, mothers may be more likely to stop breastfeeding earlier, or choose not to breastfeed, if their infants show early difficulties with self-regulation.”

The authors also want to avoid contributing to guilt or pressure surrounding infant feeding choices. “Breastfeeding is not always possible or feasible for many families, and we do not want our findings to be used in ways that blame mothers or parents,” Jacques stated. “There are many medical, practical, and personal reasons why a mother may not breastfeed or may stop earlier than planned.”

“In our paper, we suggest that feeding infants directly at the breast makes it somewhat harder, though not impossible, for parents to control how much infants eat, compared to bottle feeding,” Jacques explained. “When bottle feeding, parents may be more tempted to focus on external cues, such as whether the bottle is empty.”

“However, feeding from a bottle does not mean that parents must override infants’ internal hunger and fullness cues,” she pointed out. “In fact, research has shown that some parents rely more on infants’ cues than on the amount consumed, regardless of feeding method.”

“The key takeaway is not that bottle feeding is inherently problematic, but that infants benefit when parents pay close attention to their signals of hunger and fullness and allow them to guide how much they eat,” Jacques added. “Even when feeding from a bottle, infants can learn to regulate their intake when caregivers respond to these cues.”

It is also possible that breastmilk contains specific nutrients that help the brain develop inhibitory control. For example, trace elements in breastmilk might support general neurological growth in young children. Separating the chemical and nutritional benefits of the milk from the behavioral practice of nursing remains a complex challenge for scientists.

Future research could look at whether other infant routines provide similar self-regulation practice. “More broadly, if our hypothesis is correct, breastfeeding is only one of many early experiences that may give infants regular opportunities to practice self-regulation,” Jacques noted. “Although prolonged breastfeeding at the breast may offer multiple benefits (including nutrition, parent-child interaction, and, as we propose, repeated practice at self-regulation), it is not the only path.”

“The larger message from this and other research is that practice matters: the more opportunities children have to exercise self-control, the stronger these skills tend to become,” Jacques said. “Experiences such as learning to self-soothe, developing sleep routines, toilet training, and other guided challenges may help build inhibitory control that can carry over into many areas of life.”

“These opportunities can take many forms across development,” she added. “Learning to wait for rewards, managing eating from a plate, practicing a musical instrument, participating in team sports, or following rules in school and group activities all give children chances to strengthen their self-regulation.”

Moving forward, the researchers plan to continue exploring these developmental links. “Our long-term goal is to continue examining how psychological, physical, and health-related factors develop and interact over time,” Jacques concluded.

The study, “Breastfeeding May Provide On-the-Job Training of Self-Regulation: Longitudinal Links with Inhibitory Control,” was authored by Sophie Jacques, Sophie Parent, Natalie Castellanos-Ryan, Jean R Séguin, and Philip David Zelazo.