Baby development: Information for the science-minded parent


© 2009-2014 Gwen Dewar, Ph.D., all rights reserved

Researchers who study baby development aim to understand one of the world’s most intriguing stories: How the human mind comes online.

The discoveries are fascinating for their own sake. But they also offer many practical insights for parents.

What does opens in a new windownormal baby sleep look like? How opens in a new windowfrequently should a baby feed? When and how do you opens in a new windowstart a baby on solid foods? How do you get a baby to opens in a new windoweat something new?

In these pages, I review research from a wide range of fields–including anthropology, medicine, psychology, evolutionary biology, and neuroscience.

If you have a new baby, you might want to start with these articles:

Otherwise, you can look up articles by topic (below).

Baby feeding

For thoughts about the timing or scheduling of feeding, see my article,  opens in a new window“The infant feeding schedule.” In addition, learn more about opens in a new window“dream feeding,” a tactic is designed to help parents of young infants get more sleep.

Breastfeeding families can find a variety of information about lactation in opens in a new windowthis collection of articles.

Introducing solids can be tricky, but you might make the transition easier by exposing babies to flavors before they begin weaning, or even before they are born. For more information, see these articles about the opens in a new windowprenatal learning of food preferences and the opens in a new windowimpact of flavors in breast milk and baby formula.

Wondering when it’s time to start solids? And how to begin? Read about the latest recommendations opens in a new windowhere.

Crying, fussing, and colic

All babies cry. But some do it a lot more than others.

For an overview and evidence-based tips, see these articles about opens in a new windowcrying, colic, and fussing.

For information about what causes colic, see opens in a new windowthis guide.

And if you’ve got a difficult baby, check out my blog post opens in a new window about great outcomes for difficult babies who’ve been raised by sensitive, responsive parents.

Language and communicating with babies

When do babies speak their first words? As I explain elsewhere, most babies have achieved this milestone by their first birthdays. But experiments suggest that some babies begin to talk by the age of 6 months. You can read more about fascinating research opens in a new windowhere.

How do babies acquire language?

Cross-cultural studies suggest that some babies can learn language in a rather passive way — by merely listening to adults talk. But other research shows that babies benefit from being involved in two-way “conversations” with their caregivers.

In fact, of the most important predictors of a baby’s language development may be the amount of time he spends in conversation with an older, competent speaker.

Does your voice change when you address a baby? It does for many people, and babies like it. The slow, repetitive, musical style of speaking is called opens in a new window“infant directed speech,” and it appears to help babies understand our emotions. There is also evidence it helps babies learn how to talk.

In addition, it makes a difference how we relate to our babies. Studies suggest that opens in a new windowmaking eye contact during conversation helps babies “tune in.” It’s a signal that tells babies we attempting to convey something meaningful.

And what we talk about matters too. When we opens in a new windowaccurately label emotions and thoughts — sharing our insights about how our children feel, as well as how others feel — kids tend to develop more secure relationships and stronger social skills. 

When do babies say their first words? Some babies begin to understand the meaning of words as early as 6 months. For these babies, it’s possible that certain babbled syllables, like “ba-ba” are attempts to speak specific words (like “bottle”). But other don’t start talking until they’re much older. Around the world, most babies have begun speaking their first words by 11-13 months. For more information, see this article about the development of baby speech.

What about baby sign language?

Some people have claimed that we can give baby development a boost by teaching infants to communicate with gestures. These claims are not supported by the latest research.

However, there’s evidence that we help our babies decipher new words when we use expressive gestures, like pointing at an object we’re talking about. And it’s plausible that “baby sign language” improves communication between parents and infants, and this may benefit the parent-child relationship. To learn more, check out this article about the opens in a new windowscience of baby signing.

Learning, awareness, and memory

Once, the Western medical establishment claimed that the mind of the newborn was a blank slate. Today we know better.

As I note below, babies are born with opens in a new window strong biases for social interaction and social learning. Babies also show surprising intellectual abilities. For instance, clever experiments reveal that your opens in a new windowbaby’s mathematical mind is working even before she can talk.

What about claims that babies can’t remember?  In opens in a new windowthis post for my blog on Psychology Today I put this strange myth to rest.


Wondering opens in a new windowhow many hours your baby should sleep? Looking for evidence-based tips about solving opens in a new windowbaby sleep problems? Or just a savvy, cross-cultural guide to opens in a new windowwhat’s normal? Check out this collection of opens in a new windowevidence-based articles on baby sleep.

In addition, learn more about opens in a new windowdream feeding, which might help you improve your own sleep by tweaking the timing of your baby’s meals.

And if you are concerned about sudden infant death syndrome, see this overview of the opens in a new windowscience of SIDS and these opens in a new windowresearch-based tips for reducing the risk of SIDS.

Social intelligence and baby development

At birth, babies are already primed to interact with their caregivers.

Research reveals that mothers and babies who exchange “loving looks and coos” actually synchronize their heart rhythms (Feldman et al 2011). And babies raised by sensitive, responsive caregivers are more likely to develop secure attachment relationships.

But babies don’t just attend to you. Babies also pay attention to the interactions of third parties, and by 10 months seem to understand that some people have higher social status than others (Thomsen et al 2011).

By 12 to 14 months, many babies start showing signs of empathy and empathic concern for other people. They want to help strangers (Warneken et al 2007) and they consider the perspectives of other people (Upshaw 2015; Poulin-Dubois et al 2011; Zmyj et al 2010).

Is it helpful to understand these things? I think so.

Research suggests that that babies benefit when their parents treat them as individuals with minds of their own. This “mind-minded” approach to parenting is associated with more secure attachment relationships. It may also help babies learn about the emotions and mental processes of other people.

Stress in babies

Can babies sense when we’re stressed out? You bet. Can babies tell when their parents are fighting? Once again, the answer is yes. And the distress is contagious. When we’re upset, our babies become upset. When the stress is chronic, it affects their development.

What can we do about it? Research indicates that sensitive, responsive parenting makes a big difference. Babies with the healthiest stress response systems have parents who are sensitive and responsive to their needs. And as children grow up, they benefit from opens in a new windowpositive parenting tactics, like opens in a new windowemotion coaching.

But how do you handle a stressed-out baby when he or she is very young — too young to talk?

Research confirms that some babies are more prone to irritability than others. Some respond more negatively to being bathed or moved or having their diapers changed. But if parents tune into their babies’ signals, they can make these experiences less stressful, and help their babies develop better emotional self-regulation. Read these evidence-based tips for handling everyday stress in babies.

Toilet training: When are babies ready?

In most non-Western cultures, people start potty training in infancy. Is this something you’d like to try? Check out this evidence-based guide to  opens in a new windowinfant toilet training. You might also be interested in this opens in a new windowexperimentally-tested technique for training older babies.

What about psychological damage? What about Freud? The idea that early potty training causes psychological or behavioral problems has been discredited. For a review of the evidence, see this article about the timing of toilet training.

References: Baby development

Feldman R, Magori-Cohen R, Galili G, Singer M, Louzoun Y. 2011. Mother and infant coordinate heart rhythms through episodes of interaction synchrony. Infant Behav Dev. 34(4):569-77.

Poulin-Dubois D, Brooker I, Polonia A. 2011. Infants prefer to imitate a reliable person. Infant Behav Dev. 34(2):303-9.

Thomsen L, Frankenhuis WE, Ingold-Smith M, Carey S. 2011. Big and mighty: preverbal infants mentally represent social dominance. Science. 331(6016):477-80.

Upshaw MB, Kaiser CR, Sommerville JA. 2015. Parents’ empathic perspective taking and altruistic behavior predicts infants’ arousal to others’ emotions. Front Psychol. 6:360.

Warneken F and Tomasello M. 2007. Helping and cooperation at 14 months of age. Infancy 11(3): 217-294.

Zmyj N, Buttelmann D, Carpenter M, Daum MM. 2010. The reliability of a model influences 14-month-olds’ imitation. J Exp Child Psychol. 106(4):208-20.


For additional references, follow the links the original articles. They included full citations of the research under discussion.

photo of mother and infant © Seth

Content of “Baby development and parenting for the science-minded” last modified 2/2014