Fetuses can hear in the womb, and, as a result, newborn babies are already familiar with their mothers' voices. In experiments using playbacks of recorded voices, newborns prefer their mothers' voices to the voices of other women (DeCasper and Fifer 1980).

Moreover, maternal sounds can have a marked, soothing, physiological effect. In a study of infants born preterm, infants experience slower heart rates when they heard their mothers' voices (Rand and Lahav 2014).

Newborns recognize their native language

Every language has its own characteristic rhythms, and babies are savvy to them. In an experiment on 4-day old infants, Mehler and colleagues presented French babies with recordings of a bilingual speaker telling the same story—once in French, and once in Russian. The babies—who had "overheard" French in the womb—showed a clear preference for the French version of the story (Mehler et al 1987).

Newborns know about (and prefer to look at) faces

In experiments, new infants have shown a preference for looking at faces and face-like stimuli (e.g., Batki et al 2000; Turati et al 2002). The babies are pretty discriminating, too. For example, they show a preference for faces with open eyes. Given a choice between fearful and smiling faces, newborns look longer at happy faces (Farroni et al 2007).

Newborns can identify their parents' faces

A neonate can't see very well. Her vision is blurry, and her visual acuity is sharpest at the edges, rather than the center, of her visual field. Nevertheless, it appears that babies can learn to recognize faces in the first few hours of life.

In one study, researchers presented babies with video playbacks of women's faces (Bushnell et al 1989). The infants—who were between 12 and 36 hours old—showed a clear preference for watching their mothers' faces (rather than the faces of strangers). Other studies have replicated these results, and offer insight into the clues that babies use to tell people apart: They are probably noticing differences in face shape, hairstyle, and color (Pascalis et al 1994).

Newborns prefer to look at people who make direct eye contact and talk to them

Babies don't always want to stare into your eyes. It can be pretty intense, and babies sometimes break contact when they are tired or overstimulated.

However, like many adults, newborns show a preference for faces that make eye contact. In one experiment, researchers presented infants with a choice of two faces to look at--one with direct gaze, the other with averted gaze. The babies looked longer at the face with direct gaze (Farroni et al 2002).

In another study, newborn babies looked longer at the photographs of strangers who had previously talked to them -- but only if the talk had been accompanied by the stranger's direct gaze (Guellai and Streri 2011). More recent experiments suggest that the flipped case is also true. Babies looked longer at photographs of strangers displaying direct gaze, but only when those strangers had previously looked at and talked to them (Guellai et al 2015).

So from the very beginning, infants are attuned to multiple signals of social interaction. They pay more attention to people who make eye contact and who engage them in one-on-one "conversation."

Young babies become distressed when caregivers look emotionally unresponsive

It's one thing to prefer to eye contact and talk. Do new babies also prefer animation -- faces that are expressive and responsive? You might assume such preferences would take time to develop, but research suggests they emerge very early. The method for testing is called the "still face paradigm," and it works like this: An adult -- typically the caregiver -- is asked to interact in a normal way with the baby. Then the adult suddenly adopts a neutral facial expression. The baby's reactions are recorded and analyzed.

Still face experiments conducted in Switzerland have shown babies as young as 6 weeks "reliably decreased their visual attention and positive affect" [emotion] when their adult partners faces go blank (Bertin and Striano 2006). A study of 2-month-old babies in Taiwan obtained similar results (Hsu and Jeng 2008). In Scotland, Emese Nagy (2008) detected signs of distress in babies less than 4 days old.

Newborn babies pay more attention to things that you are looking at

If I follow your gaze, I can figure out all sorts of things: What you are looking at, what your intentions are, and what you might do next. Thus, gaze-following is a important tool for learning. It draws a baby's attention to important things in the environment, and helps babies develop an understanding of other people's minds.

Studies show that gaze-following in older babies (6-12 months) predicts the development of language skills and social competence (Tenebaum et al 2014; Young et al 2009; Carpenter et al 1998). And recent research suggests that even newborns practice a rudimentary form of it.

In one experiment, Teresa Farroni and colleagues showed new babies (ranging in age from 2 to 5 days) pictures of some crude, cartoonish faces with large eyes. The pupils of these cartoonish eyes could move from side to side, giving the appearance of a shifting gaze. There were two conditions.

1. Congruent: The face's gaze shifted towards a bull's-eye that flickered in the corner of the picture.

2. Incongruent: The face's gaze shifted away from the flickering bull's-eye.

As the infants watched these pictures, their eye movements were captured on videotape. In this way, the researchers were able to measure the infants' saccades—rapid, darting movements of the eye that are often involuntary and unconscious.

The results supported the idea that newborns pay attention to gaze. When the infants were cued by gaze, they were faster to make saccades to the bull's-eye (Farroni et al 2004).

Newborns are responsive to our facial expressions and gestures

In 1983, Andrew Meltzoff and Keith Moore performed a landmark experiment. They presented babies (ranging in age from 1 hour to 3 days old) with video playbacks of a stranger making faces. In one condition, the stranger stuck out his tongue. In another condition, he opened his mouth.

The results surprised many people who believed newborns were passive, socially unresponsive creatures: In the 20 seconds following each presentation, babies were more likely to match the action they had just watched (1983). Subsequent studies have replicated the effect, even in nonhuman primates, like this newborn macaque (Gross 2006).

So it appears to be a response with deep evolutionary roots, though human babies respond a bit differently. Unlike the monkey, our babies are more likely to mirror a "tongue out" expression when they are lying down or sitting in an infant seat (Nagy et al 2013).

Is this imitation? Maybe not. When Janine Oostenbroek and colleagues revisited the phenomenon, they wanted to know if newborns are sticking their tongues out to match us, or doing it as a natural response to face-to-face communication. Maybe babies are just as likely to do it when we smile or gesture with our hands.

The researchers ran their own matching experiments, adding new controls, and found they were right to be suspicious: Newborns stuck their tongues out in response to several different displays, including happy faces and finger pointing gestures, and the babies didn't appear to imitate anything (Oosterbroek et al 2016).

Still, it's premature to conclude that newborns can't mimic us at all. In a series of experiments conducted by Emese Nagy and her colleagues (2014), 2-day-old infants were more likely to raise their index fingers after seeing their mothers do the same. They also mirrored gestures involving the movement of 2 fingers (making the "peace sign"). Moreover, the babies showed rapid learning, their gestures becoming more accurate with practice.

And all of these studies confirm a crucial developmental fact: Newborns are attentive and responsive to face-to-face communication, and ready to learn. Oosterbroek's coauthor, Virginia Slaughter, thinks that we may give our babies a boost when we imitate them. She notes that in previous research, her team has found that "parents imitate their babies once every two minutes on average; this is a powerful means by which infants can learn to link their gestures with those of another person" (Caputo 2016).

Newborn babies show empathy...and a sense of self ?

If you've visited the newborn ward, you've probably noticed that crying is contagious. If a newborn baby hears another baby cry, she joins in, too.

Is just a knee-jerk reaction to noise? Apparently not. Studies show that newborns are discriminating. They can tell the difference between the sounds of

• their own cries
• the cries of other newborns, and
• the cries of older babies

And newborns are more likely to cry only if they hear the cries of other newborns.

The evidence comes from experiments in which researchers played back audio recordings to newborns. In one study, 1-day-old babies were more likely to cry when they heard an audio tape of another newborn in distress. But when they heard recordings of their own cries, or of the cries of an 11-month-old baby, the newborns didn't respond (Martin and Clark 1987).

A similar study found that new babies showed greater and longer lasting signs of distress when they listened to the cries of others (Dondi et al 1999).

And in case you are wondering, this isn't some newborn reflex that disappears after the first few days of life. When researchers tested babies at months 1, 3, 6 and 9, they found that older babies, like newborns, responded with distress when they heard cries of pain (Geangu et al 2010).

As neuroscientists Jean Decety and Philip Jackson note, the crying studies suggest that young babies experience one of the basic ingredients of empathy--the ability to share the emotions of another person. They also suggest that newborns have a sense of self (Decety and Jackson 2004).

What are the implications?

In times past, some people believed that newborns were effectively mindless: tiny survival machines that depended on us for food and shelter. But the studies cited here confirm that newborn babies are fundamentally social creatures. They seem designed to listen to speech, to seek out and differentiate faces, and to expect responsive social partners.

So perhaps the most important, practical lesson is to be on our guard against assumptions about the limitations of babies. If we take the position that newborns need little more than feeding and diaper changes, we may miss important opportunities to connect with them.

And while there's still a lot we don't understand about babies, the evidence supports a pro-mentalistic stance. Studies suggest that babies develop stronger attachment relationships when we treat them like creatures with independent minds. Science has also demonstrated the protective effects of positive, sensitive social interactions on a baby's developing stress response system. So if we have to err, let's err on the side of attributing too much "mind" to our babies. We have little to lose, and who knows? Future studies might reveal that our generous attributions were right on target.