New parents are notorious for looking for early signs of their infant’s intelligence—a babbled first word, waving or blowing kisses, a spark of recognition when they see a familiar face. Most of the time it's just an attempt to prove their baby is just as special as their parents know they are—but it might actually be possible to predict a person's adult IQ in infancy?

A new study from the University of Colorado Boulder suggests your baby will show signs of intelligence just as early as new parents are convinced they can. In fact, researchers found that it may be possible to predict how well a person will perform on a cognitive test in their 30s as early as 7 months old.

So, how exactly can a baby’s brain reveal its future potential?

To find out, University of Colorado Boulder researchers recruited 500 families with twins (both fraternal and identical). They followed participants at 7 and 9 months, then at age 1, and every year until age 17, continuing every five years into their 30s.

Analyzing the decades of data collected from their participants, the goal was to better understand how genes and environment interact to shape a child’s development.

By studying twins, researchers could determine the distinct roles that genes and shared environment play. Since identical twins share 100% of their genes while fraternal twins share only about 50% (like regular siblings), comparing their IQ similarities allowed researchers to infer how much of cognitive ability is due to genetics versus shared environmental factors. 

Daniel Gustavson, PhD, an assistant research professor at the University of Colorado Boulder and lead author on the study, says a shared environment includes “all the aspects of their home, neighborhood, school environments.”

The study found that early on, the environment (before age three) can have a measurable and lasting impact on a person's cognitive ability later in life, accounting for around 10% of individual differences in IQ, Dr. Gustavson notes. 

To test infant cognition, researchers used seven measures, including the “novelty preference” task that assessed how long infants spend looking at a new toy versus a familiar one, vocalizations (babbling sounds made by the infant), visual expectation (tracking an object), tester ratings (attentiveness, activity, mood), and the Bayley Scales of Infant and Toddler Development.  

While these specific infant tests (at seven to nine months) predicted only a small percentage of an adult’s IQ, the study found that by age three, the yearly follow-ups could predict 20% of what Dr. Gustavson calls “across-person differences” in IQ. This prediction rapidly increased between ages seven and 16, a period when he says genetics “really start to take hold.”

Although the genes we inherit significantly contribute to our IQ, Dr. Gustavson wants parents to know that heritability doesn’t mean “we can’t change who we’re going to become.” There are always ways to intervene and learn new skills.

The study emphasizes that early environment matters, but it doesn't specify how parents can best nurture cognitive growth. 

To bridge that gap, we spoke with Sara Douglas, PsyD, Ed.M, a psychologist specializing in neuropsychological evaluations, and pediatrician Heather Gosnell, MD, to offer helpful suggestions.

IQ is often viewed as a singular number, but Dr. Douglas says it’s essential to look at IQ as one’s capacity “within multiple traits and features.” Here are some simple strategies for holistically nurturing cognitive development in young kids.

Viewed this way, a stimulating environment can provide exposure that enhances these traits. Dr. Douglas suggests allowing an infant “to spend time feeling different textures, seeing different patterns, hearing different notes, [and] interacting with different people.” 

She adds it’s a good idea to “provide different opportunities for novel experiences. If possible, provide different experiences in the different weeks of development, so young kids have the opportunity both to learn the first [skill], and expand their interest to the next.”

Parent-child interaction is also key, says Dr. Gosnell, because “simple routines like reading, talking, and playing have a powerful impact on brain development and set the foundation for learning.” 

She recommends reading twenty minutes a day to your infant and continuing this routine through childhood as it supports at-home brain development. You can also narrate your day to help build language skills. And if possible, avoid screen time before 18 months. Once introduced, she says to choose quality programming, watch together, and limit screen time to one hour a day. 

Remember that this study does not indicate that intelligence is a binary—it’s not the case that either they show signs of intelligence early on and will grow upto intelligent, or they don’t, and they won’t. Intelligence can develop over time, starting with parents who use some of the strategies outlined above. 

And it doesn’t help to stress out over these milestones that will vary from child to child anyway.

“Don't worry if your baby isn't 'advanced' in every area or if they miss one milestone, as uneven development is completely typical,” says Dr. Gosnell.

Late talking and short attention spans are also not a cause for concern. “Most late talkers catch up by age 4 to 7, especially when they understand well, are developing normally in other areas, and receive speech therapy if needed,” Gosnell states. “Toddlers naturally have very brief focus periods, which is normal and, on their own, don’t predict future attention problems.”

And remember—IQ and intelligence isn’t everything, and definitely does not indicate that your child will be a good person or a productive member of society. 

“There are personality traits (like kindness, empathy, genuineness, being a good listener),” says Dr. Douglas, “that are not factored into intelligence testing that are, in many regards, more important than cognitive traits that are measured.”