Why Keep Babies Happy? A baby’s cry is a late signal of discomfort

By Dr. Darcia Narvaez

It’s quite common to hear babies cry in movies and television with adults mostly ignoring the baby’s unhappiness. I shake my head. Why are they ignoring baby’s signals? Ignorance? Cruelty? Numbness?

Don’t they know that babies are like fetuses (of other animals) until 18 months of age (Trevathan, 2011)? And so, babies need sensitive, responsive care to keep them in an optimal state while the brain is rapidly growing and setting up its systems and the child’s personality (in response to experience)? Don’t they know the research showing that sensitive care is linked to better and more growth (e.g., Moore et al., 2017) and to all sorts of short and long term outcomes—like mental and physical health (Lanius et al., 2010; Perry et al., 1995)?

A recent study shows that stress in the first two months of life may have a greater impact on central nervous system (CNS) functioning that lasts at least into adolescence (Hambrick et al., 2018). The researchers wanted to study relational poverty and trauma. In a sample of 3,523 children between the age of 6 to 13, ratings of relational health and adverse experiences were tabulated for previous developmental periods (perinatal: 0-2 months; infancy: 2-12 months; early childhood 13 months-4 years; childhood 4-11 years). Relational health was measured as "primary caregiver safety, primary caregiver attunement, consistency in primary caregiving, paternal (or partner) support, kinship support, and community support." 

Of all prior periods of life, experiences in the first two months of life had the strongest association with children's CNS functioning, though current relational health was the most predictive of current functioning. CNS functioning was measured as age-typical "cardiovascular regulation (heart rate), sleep, feeding/appetite, fine motor skills, affect regulation, relational skills, arousal, ability to modulate reactivity/inhibit impulsivity, and abstract/reflective thinking skills."

The potential long-term effects of early experience are not a surprise if you know that human infants are like fetuses of other animals until they are 18 months of age (Montagu, 1968; Trevathan, 2011) and are highly malleable from social experience in the early years of life (Schore, 2019).

Here is new evidence of the importance of keeping babies happy. A longitudinal study by John Coffey (2019) shows that happiness at 18 months predicts educational success at age 29 directly and also indirectly through IQ measures in childhood.

Here is the abstract in bullets:

• “Parents want their children to be happy, educated, and successful, but are these goals related?
• People assume that success leads to happiness, but research on adults supports a reverse conceptualization: Happy people are more successful. Is happiness during childhood also linked to later success? Across the lifespan positive affect is linked with expanded cognitive abilities, learning, and resource building that can be adaptive and useful such that it leads to more success.
• Conversely, ongoing negative affect can reduce opportunities for growth and learning. Thus, happiness at any age may predict future success.
• Yet, no research has examined if positive and negative affect during infancy predicts childhood cognitive abilities and adult academics success.
• In a community sample, I hypothesized that higher infant positive affect (but not negative affect) would predict higher childhood cognitive abilities (i.e., IQ) and adult academic success (i.e., education attainment) in a 29-year study (n _ 130).
• Positive affect, but not negative affect, during infancy (age 1.5), directly predicted higher childhood IQ (ages 6–8) and higher educational attainment (age 29), even after controlling for family socioeconomic status and infant intelligence.
• Childhood IQ partially explained the link between positive affect during infancy and adult educational attainment.
• This study advances understanding of how happiness during infancy (before formal education has begun) is linked to gold standard indicators of cognitive abilities and adult academic success.
• Parents, educators, and policymakers may want to place a higher value on early affective experiences when considering educational success.”

But how do we keep babies happy?

First, don’t let them get distressed. This means: learn the signals of the baby.

A baby’s cry is a late signal of discomfort. Babies have only a limited number of signals—body gestures, facial gestures, fussy noises and crying. Respond as soon as possible.

A baby’s fussing means they are starting to feel panic or fear, basic innate emotions in our mammalian brains (Panksepp, 1998; later the rage system can be activated too). When left in distress routinely, a sense of danger can grow into a deep insecurity, anxiety knitted into the psyche with the stress response easily activated (Sandler, 1960). The child can end up with a feeling of badness and abandonment, leading to insecure attachment with that caregiver. Without the benefit of more supportive relationships, the child can turn into an anxious adult who will seek ways to avoid feeling those terrible feelings, cutting off the self from internal and external stimuli (losing the self and losing relationships) so that fantasy takes over (Schore, 2003). The primitive systems of rage and fear can only be calmed down with ritual actions, false narratives and one or more false selves (Laing, 1990).

Feeling abandoned and unloved, the individual moves forward with necessary self-protective distortions and falsities. In a recent paper of mine for the Oxford Handbook of Philosophy and Psychoanalysis, I wrote:

“Avoidance of a sense of non-being, of shame, and of annihilation shapes actions and reactions, with negative transferences to others predominating. Thus, self protectionist ethics reflect an enhancement of the survival systems through early conditioning while right-hemisphere lateralized self-regulatory and relational capacities are underdeveloped or shut down. Unable to stand negative feelings towards the self (e.g. guilt), the individual slides into bullying or being victimized as comfortable psychic locations. What becomes normalized is a role in a dominance hierarchy, either through aggressive action or through appeasement or withdrawal. The self-protective individual is not relaxed and open but braced against others.” (Narvaez, 2019, p. 652)

Second, do what traditional communities do around the world and your ancestors did not so long ago:

• Respond to baby’s needs within a few seconds to keep them optimally aroused (Hewlett & Lamb, 2005)
• Babies expect to be held and carried (their bodies know what helps them grow), so do so as much as you can.
• Provide the evolved nest. Babies want to grow their best and the nest offers the support needed. As social mammals, nested care is what their bodies and brains evolved to expect. A recent study in my lab shows that provisioning components of the evolved nest to young children (affectionate touch and lack of corporal punishment, free play, family togetherness) promotes happiness and thriving in the samples from three countries we studied--USA, China and Switzerland (Narvaez, Woodbury et al., 2019).

References

Coffey, J. K. (2019). Cascades of Infant Happiness: Infant Positive Affect Predicts Childhood IQ and Adult Educational Attainment. Emotion. Advance online publication. http://dx.doi.org/10.1037/emo0000640

Hambrick, Erin & Brawner, Thomas & Perry, Bruce & Brandt, Kristie & Hofmeister, Christine & Collins, Jennifer. (2018). Beyond the ACE score: Examining relationships between timing of developmental adversity, relational health and developmental outcomes in children. Archives of Psychiatric Nursing. 10.1016/j.apnu.2018.11.001

Hewlett, B.S., & Lamb, M.E. (2005). Hunter-gatherer childhoods: Evolutionary, developmental and cultural perspectives. New Brunswick, NJ: Aldine.

Laing, R.D. (1959/1990). The divided self. London: Penguin.

Lanius, R. A., Vermetten, E., & Pain, C. (Eds.) (2010). The impact of early life trauma on health and disease: The hidden epidemic. New York, NY: Cambridge University Press.

Montagu, A. (1968). Brains, genes, culture, immaturity, and gestation. In A. Montagu (Ed.) Culture: Man’s adaptive dimension (pp. 102-113). New York: Oxford University Press.

Moore, Sarah R., Lisa M. McEwen, Jill Quirt, Alex Morin, Sarah M. Mah, Ronald G. Barr, W. Thomas Boyce, Michael S. Kobor. Epigenetic correlates of neonatal contact in humans. Development and Psychopathology, 2017; 29 (05): 1517 DOI: 10.1017/S0954579417001213

Narvaez, D. (2019). Evolution, childhood and the moral self. In R. Gipps & M. Lacewing (Eds.), The Oxford handbook of philosophy and psychoanalysis (pp. 637-659). London: Oxford University Press. DOI: 10.1093/oxfordhb/9780198789703.013.39

Narvaez, D., Woodbury, R., Gleason, T., Kurth, A., Cheng, A., Wang, L., Deng, L., Gutzwiller-Helfenfinger, E., Christen, M., & Näpflin, C. (2019). Evolved Development Niche Provision: Moral socialization, social maladaptation and social thriving in three countries. Sage Open, 9(2). https://doi.org/10.1177/2158244019840123

Panksepp, J. (1998). Affective neuroscience: The foundations of human and animal emotions. New York: Oxford University Press.

Perry, B. D., Pollard, R. A., Blakely, T. L., Baker, W. L., & Vigilante, D. (1995). Childhood trauma, the neurobiology of adaptation, and “use-dependent” development of the brain: How “states” become “traits.” Infant Mental Health Journal, 16, 271–291.

Sandler, J. (1960). The background of safety. International Journal of Psychoanalysis, 41, 352-356.

Schore, A. N. (2003). Affect dysregulation & disorders of the self. New York, NY: Norton.

Schore, A.N. (2019). The development of the unconscious mind. New York: W.W. Norton.

Trevathan, W. R. (2011). Human birth: An evolutionary perspective, 2nd ed.. New York: Aldine de Gruyter.

Related Reading by Dr. Narvaez at Peaceful Parenting: 

An 'On Demand' Life and the Basic Needs of Babies

Where Are All the Happy Babies?

The Dangers of Crying It Out

10 Things Everyone Should Know About Babies

5 Things NOT to Do to Babies

12 Ways to Nurture Babies at Conception, Birth, and Beyond

Are you treating your child like a prisoner?

Are you or your child on a touch starvation diet?

Conspiracy Thinking: Understanding Attachment and Its Consequences

Psychology Today: Circumcision Series

Learn More from Narvaez:

The Evolved Nest Institute

Kindred Media

Neurobiology and the Development of Human Morality: Evolution, Culture, and Wisdom

💜 Peaceful Parenting Community

💙 Peaceful Parenting on Facebook

💗 Peaceful Parenting on Telegram

Love the Skin that You're In!

'Love the skin you're in' watercolor painting by Rachel Toll, Devon England.

Visit Toll's original art store here.

Three good friends went for a swim. 

The one who was fat wished she was thin. 

The one who was curvy wished she was clever. 

The one who was clever wished she swam better. 

The really great swimmer wished she was witty. 

The one who was witty wished she was pretty. 

All three friends thought the other two were just fine. 

If only they could let their own bright light shine. 

So throw on your swimsuit if you're fat or you're thin. 

Enjoy fun and friendship...

Love the skin that you're in!

-Author Unknown

*******

Peaceful Parenting Community

I'm Intact - Do NOT Retract Soft Baby Bands

A handy little soft baby band reads: Do NOT Circumcise / Do NOT Retract for those birthing in a U.S. hospital or birth center (and reusable for clinical visits or babysitters as a reminder going forward to not retract). These small bands come with intact care materials which Peaceful Parenting families have found to be incredibly useful for hospital charts and staff.

Found at Etsy here.

Intact Care Resources: http://www.DrMomma.org/2009/06/how-to-care-for-intact-penis-protect.html

Safe space groups:

• Intact: Healthy, Happy, Whole (questions, education only)
• Saving Our Sons Community (for advocates)
• Peaceful Parenting Community (gentle parenting) 

Photo courtesy of Elana at the Intact Jewish Network

5 Things NOT to Do to Babies

When I had a puppy, he hated to be ignored or left alone. At those times he would chew up the furniture. Babies hate these things too, but they can’t damage the furniture to let us know. Instead, their development gets undermined and we and society have to live with the anxious and depressed results.

What should we NOT do to babies?

1. Ignore them (don’t)

Under natural birth conditions, newborns are ready to communicate with mother, father and others. Colwyn Trevarthen has videos showing newborn communication with a parent. Of course, they cannot talk but they can grunt and move their arms (the left arm is typically self-referential and the right arm focused on the partner). Some mothers communicate with the baby in the womb through singing, reading, talking, or even thumping. In indigenous cultures, the mother is responsible for shaping the spirit of the child with communications like these to the baby before and after birth, even creating a unique song for that child (e.g., Turnbull, 1983).

Grazyna Kochanska’s (2002) program of research shows that it is a “mutually-responsive orientation” that leads over time to the most positive outcomes, like conscience, prosocial behavior, and friendship skills. Mutually-responsive means the parent and child both influence each other, building a relationship cooperatively. Trevarthen (1979, 1999, 2001) suggests that this type of companionship care provides an optimal environment for emotional and intellectual development. The parent and child together develop their own ongoing creative stories and games that continue to change over time. 

Why is a companionship relationship particularly important for babies? The first three years of life is a time when tacit (non-conscious) understanding of how the social world works is developed and it gets wired into how the brain works (Schore, 1994, 1996). With responsive care, the brain’s systems learn to work well and thereby keep the person healthy and socially engaged. What is learned during early life will be applied ever after to relationships (unless changed with therapy or other significant brain-changing experiences). 

Babies who are born early or experience non-soothing perinatal experiences may need to be gently wooed by caregivers into a back-and-forth communicative relationship. This means caregivers have to be especially calming and sensitive to the baby’s signals—teasing her into relating, but only when she is ready. Skin-to-skin touch, singing and whispering comforting words may be helpful for the very withdrawn.

2. Let them cry (don’t)

Imagine being in pain and asking for help and being ignored. How does that make you feel about yourself (bad) and about your family (angry)? It’s so much worse for a baby; he has rapidly growing brain systems that are learning their dance patterns for social living and for physiological functioning.

If babies regularly get distressed, their bodies are being trained to be anxious and distrustful of themselves and of others. Most of what they learn from undercare is tacit knowledge that may not be noticeable until later when they are inflexible, self-centered and easily stressed out. Know anyone like that?

When young babies cry they are not having tantrums or being little emperors. They have needs and communicate them the only way that they can.

But if you wait for a cry before alleviating discomfort, you are waiting too long.

Young babies have a hard time stopping crying so you don’t want to let them start. To keep babies from crying, caregivers must pay attention to the nonverbal signals babies give (restlessness, frown, grimace, flailing arms) and nip discomfort in the bud. This is what wise grandmothers do.

Young babies need to breastfeed frequently, as human breastmilk is thin but filled with the body’s building blocks. Babies also need to move a lot, which helps them grow. So if you know the baby just had a good feed, then keep him calm with patting, bouncing, rocking. They expect the caregiver to be emotionally present with skin-to-skin contact, so talk, sing, be.

In the first four months of life, babies are likely to be more fussy (but that doesn’t mean they must cry). This is also the time period that seems to set the level of responsiveness between baby and caregiver that lasts for years after (according to our and Ruth Feldman’s research; Feldman, Greenbaum & Yirmiya, 1999). Caregivers should be especially attentive to when a young baby starts to fuss by noticing facial expression and gestures and offer preventative comfort that relaxes them again. Preventing crying in the first place is the goal (and ancient wisdom). 

A mother visited my class with a baby a few months old. We passed the baby around until he began to grimace. Then the mother took him, stood up and held him in her arm, stomach down and rocked and bounced him back and forth. He looked very content and remained quiet for the rest of the period.

Now, I should say that if a caregiver is feeling so frustrated that she is ready to throw the baby against the wall, in that case, it is best to leave the room and let the baby cry. (See Period of Purple Cry for guidelines; and see these cautions.) But of course, it is best not to let such a regular crying pattern get established in the first days and weeks of life. 

3. Leave them alone (don’t) 

Babies are built to be physically connected to caregivers. They do not understand why they are alone.

Imagine being suddenly left alone in a strange land where you cannot move or take care of yourself. It would be terrifying, even if you understood what was going on. Why do this to a child? 

Children are mammals who rely on the companionship of adults to care for their needs until they can do it themselves. Although people talk as if you can force babies to learn independence, this is an imaginary outcome. If you isolate babies, the opposite happens—they become whiney and needy or quiet and torn up inside, in both cases preoccupied with themselves.

One of the hallmarks of people who don’t help others when they are in a situation of need is personal distress (Batson, 2011). Personal distress makes empathy and compassionate action very unlikely. Making babies stress reactive from undercare may be a good way to build an easily distressed personality and create a society of self-concerned folks. 

4. Not hold them whenever possible (please hold them) 

Babies are meant to be held. This should start immediately. First impressions of you and the world are fundamental. Can they relax into being? Learning a deep relaxation and sense of peace is what they will carry forward into life. If they don’t have a regular experience of relaxing into loving arms, they may never learn to relax and let go. Such a letting go is vital for health (Kabat-Zinn, 1991). 

When babies are physically apart from caregivers (not “in arms”), pain responses are activated, influencing the presence of various hormones and neuropeptides right when systems are being established (Ladd, Owens & Nemeroff, 1996; Panksepp, 2003; Sanchez et al., 2001). Separation dysregulates multiple systems over the long term. For example, the hypothalamic-pituitary-adrenal axis (HPA), a part of the stress response system becomes dysregulated and hyperactive (Caldji, Tannenbaum, Sharma, et al., 1998; Levine, 1994; Plotsky & Meaney, 1993). Even a 3-hour daily separation (in infant mice—and human babies are much more needy and social) caused enough early life stress to induce epigenetic effects that heightened stress reactivity and caused deficits in memory function in adulthood (Murgatroyd & Spengler, 2009). Moreover, limited touch in early life leads to an underdevelopment of serotonin receptors, endogenous opioids and oxytocin—chemicals that are related to happiness (Kalin, 1993; Meinischmidt & Heim, 2007). 

So don’t take untouched babies lightly.

Babies should feel welcome in adult arms apart from the times they themselves feel the urge to explore (though a fearful toddler may sometimes need encouragement to explore). When babies want to explore, it should be allowed as much as possible. 

Here is an interesting anecdote. When an American was visiting an African village, she saw a young child reaching for the fire and automatically slapped his hand away. An African elder scolded her for doing so, saying, ‘if you do that you will have to watch him carefully for the rest of his life.’ That is, children need to learn about their own world without being overguarded or they will never learn to behave safely on their own.

Numbers 1-4 are punishing. Babies are not meant to be without adult caring companionship at any time and don’t grow as well without it. But there is one more specifically about intentional punishment of babies. 

5. Punish them (don’t)

Some parents spank or hit their babies (almost 1/3 of 12-month-olds in the USA are spanked, according to recent research)! This is very bad news. Corporal punishment might be an immediate release of frustration for the caregiver but, like most aggressive acts, it can have long-term negative effects.

Recall that babies are learning what life is about from the way they are treated and what they practice. Punishment has several obvious damaging effects: 

(a) The baby may have less trust in a caregiver’s love and care, as the caregiver is not safe to relax around;

(b) The baby may have less trust in himself—caregivers have taught him that his urges are unimportant and even bad to have—talk about how to undermine self-development;

(c) If caregivers punish babies for wanting to explore, they may undermine motivation for learning (affecting school achievement later);  

(d) The baby may learn that it’s best to suppress her interests around the caregiver, influencing communication with the caregiver;

(e) A recent study of audio recordings of families shows not only that parents are very impatient but that misbehavior increases after spanking.

(f) Physiologically, punishment will activate the stress response, which is not advisable in early life when thresholds and parameters for functioning are being set.

If you want to optimize a baby’s brain, health and wellbeing for the long term, don’t do these five things.

Warm, responsive parenting is one of the best predictors of positive child outcomes (e.g., getting along with others, doing well in school). Responsive caregiving means attending to the individuality of the child in a particular situation. So caregivers have to be emotionally present, not distracted by their own worries, phones or work. 

“But I’m a tired, frustrated parent” 

Clearly babies take a lot of care to get them off to a good start. That’s why the adage “it takes a village to raise a child” is often mentioned. Yes, it takes more than one person (usually mom) or even two people (usually mom and dad) to meet one baby’s needs. So if you are a frustrated, tired parent, get help with caregiving. Here are just a few examples from experience but parents, please add suggestions:

(a) Arrange gatherings with other families, exchange babysitting, share meal making and clean up.

(b) Lower expectations for your personal goals. I remember hearing a mother say after several months of struggle that she learned to surrender to the needs of the baby. Taking care of baby’s needs is an investment you won’t regret. 

(c) If you can, have one parent or adult family member not work outside the home so she or he can focus on childcare (which should decrease stress). Apparently, stay-at-home mothering has been increasing. This is a good idea as long as parents don’t isolate themselves with their children.

(d) Parenting is not meant to be a solo act. Parents should structure their lives around support systems. And everyone should all give parents help whenever possible.

Babies follow built-in needs (see Ten Things Everyone Should Know About Babies). Deny them at the peril of making a less healthy, happy and agreeable child.

NOTE on BASIC ASSUMPTIONS: When I write about parenting, I assume the importance of the evolved developmental niche (EDN) for raising human infants (which initially arose over 30 million years ago with the emergence of the social mammals and has been slightly altered among human groups based on anthropological research).

The EDN is the baseline I use for determining what fosters optimal human health, wellbeing and compassionate morality. The niche includes at least the following: infant-initiated breastfeeding for several years, nearly constant touch early, responsiveness to needs so the young child does not get distressed, playful companionship with multi-aged playmates, multiple adult caregivers, positive social support, and soothing perinatal experiences.

All these characteristics are linked to health in mammalian and human studies (for reviews, see Narvaez, Panksepp, Schore & Gleason, 2013; Narvaez, Valentino, Fuentes, McKenna & Gray, 2014; Narvaez, 2014) Thus, shifts away from the EDN baseline are risky. My comments and posts stem from these basic assumptions.

Related Reading

More on what scholars say about early nurturing here.

How raising babies is different from raising children.

Related Reading by Dr. Narvaez at Peaceful Parenting: 

An 'On Demand' Life and the Basic Needs of Babies

Where Are All the Happy Babies?

The Dangers of Crying It Out

10 Things Everyone Should Know About Babies

Why Keep Babies Happy? A baby's cry is a late signal of discomfort

5 Things NOT to Do to Babies

12 Ways to Nurture Babies at Conception, Birth, and Beyond

Are you treating your child like a prisoner?

Are you or your child on a touch starvation diet?

Conspiracy Thinking: Understanding Attachment and Its Consequences

Psychology Today: Circumcision Series

Learn More from Narvaez:

The Evolved Nest Institute

Kindred Media

Neurobiology and the Development of Human Morality: Evolution, Culture, and Wisdom

💜 Peaceful Parenting Community

💙 Peaceful Parenting on Facebook

💗 Peaceful Parenting on Telegram

References

Batson, C.D. (2011). Altruism in humans. New York, NY: Oxford University Press.

Caldji, C., Tannenbaum, B. Sharma, S., Francis, D, Plotsky, P.M., & Meaney, M.J. (1998). Maternal care during infancy regulates the development of neural systems mediating the expression of fearfulness in the rat. Proceedings of the National Academy of Sciences USA, 95(9), 5335-5340.

Feldman, R., Greenbaum, C.W., & Yirmiya, N. (1999). Mother–infant affect synchrony as an antecedent of the emergence of self-control. Developmental Psychology, 35(1), 223-231.

Hrdy, S. (2009). Mothers and others: The evolutionary origins of mutual understanding. Cambridge, MA: Belknap Press.

Kabat-Zinn, J. (1991). Full catastrophe living: Using the wisdom of your body and mind to face stress, pain, and illness. New York: Delta.

Kalin, N. H. (1993). The neurobiology of fear. Scientific American, 268, 94–101.

Kochanska, G. (2002b). Mutually responsive orientation between mothers and their young children: A context for the early development of conscience. Current Directions in Psychological Science, 11(6), 191-195. doi:10.1111/1467-8721.00198

Ladd, C. O., Owens, M. J., & Nemeroff, C. B. (1996). Persistent changes in corticotropin-releasing factor neuronal systems induced by maternal deprivation. Endocrinology, 137, 1212–1218.

Levine, S. (1994). The ontogeny of the hypothalamic-pituitary-adrenal axis: The influence of  maternal factors. Annals of the New York Academy of Sciences, 746, 275-288.

Liedloff, J. (1986). The Continuum concept. Cambridge, MA: Perseus Books.

Meinlschmidt, G., & Heim, C. (2007). Sensitivity to intranasal oxytocin in adult men with early prenatal separations. Biological Psychiatry, 61(9), 1109-1111.

Murgatroyd, C., Spengler D (2011). Epigenetics of early child development. Frontiers in Psychiatry, 16 (2), 1-15.

Murgatroyd, C., Spengler D (2011). Epigenetics of early child development. Frontiers in Psychiatry, 16 (2), 1-15.

Plotsky, P. M., & Meaney, M. J. (1993). Early, postnatal experience alters hypothalamic corticotrophin-releasing factor (CRF) mRNA, median eminence CRF content and stress-induced release in adult rats. Molecular Brain Research, 18, 195–200.

Sanchez, M.M., Ladd, C.O., & Plotsky, P.M. (2001). Early adverse experience as a developmental risk factor for later psychopathology. Development and Psychopathology, 13(3), 419-449.

Schore, A. N. (1994). Affect regulation and the origin of the self. Hillsdale, NJ: Erlbaum.

Schore, A.N. (1996). The experience-dependent maturation of a regulatory system in the orbital prefrontal cortex and the origin of developmental psychopathology. Developmental Psychopathology, 8, 59–87.

Trevarthen, C. (1979). Communication cooperation in early infancy: A description of primary intersubjectivity. In M. Bullowa (Ed.), Before speech: The beginning of human communication (pp. 321–347). London, UK: Cambridge University Press.

Trevarthen, C. (1999). Musicality and the intrinsic motive pulse: Evidence from human psychobiology and infant communication. Musicae Scientiae, Special Issue, 157–213.

Trevarthen, C. (2001). Intrinsic motives for companionship in understanding: Their origin, development and significance for infant mental health. Infant Mental Health Journal, 22(1–2), 95–131.

Turnbull, C.M. (1983). The human cycle. New York: Simon and Schuster.