Ed Tronick’s Mutual Regulation Model describes the “dynamic organization of the behavioral communicative system” between a child and adult, “which regulates behavior moment by moment and shapes development over time” (Tronick p56). From this perspective, Dani’s development is shaped by an increasing capacity to comprehend my actions and intentions in any given moment, and to respond with an ever more complex behavioral repertoire. Likewise, my behavior towards her expands in complexity, as I adjust to each new skill and phase. Louis Sander explains that this process of “negotiating a sequence of increasingly complex tasks of adaptation, or ‘fitting together,’” with caregivers, cultivates the infant’s psychological organization. (Sander p21). Over time, through the process of relating to me and other caregivers, Dani develops a coherent sense of self.

Throughout my training in Napa, I wondered why Tronick chose peekaboo as the defining example of these essential relational dynamics. I knew the game was important developmentally. I understood how it helps infants to integrate the concept of object permanence. I knew that its maturation into hide-and-seek underscores advances in cognitive development over the first 3 years of life. But I had no idea about the levels of subtle and intricate, implicit communication woven into this deceptively simple and endlessly repetitive game – until Dani really began to play it.

At a glance, peekaboo is about cognitive development. And Dani’s current joy in playing it highlights the cognitive burst that begins around 10-months old. Suddenly, and extraordinarily rapidly, my baby understands the world in whole new ways. She knows what a hairbrush is for, and a cup and a spoon. She knows how to find her favorite lovey, and what I am saying when I encourage her to get it. She looks for her grandmother when I say the word, and she learns quickly how to find the hidden pictures in her new lift-flap book. She is grasping object permanence, and exploring its meaning. She is learning that she can initiate an interaction and we will gladly follow along.

All of these skills come into play as she dramatically expands her peekaboo repertoire. For months, Dani was just the passive recipient in the game, reacting in “messy, variable and disorganized” ways to my hiding and reappearing eyes. Slowly she began to “anticipate the coming ‘boo’” and become more organized in her response, but she was still entirely in the receiving role (Tronick, p56). At about 9.5-months old, she learned how to hold a blanket up “over” her own head. (Really she was just holding a corner of fabric in front of her face and lowering her gaze. In no way was she actually hidden from me. How fascinating to imagine that from her perspective, the hiding was complete.) She would occasionally play this way with my prompting, but she did not seem particularly excited about it, and she had yet to initiate the game on her own.

Then one day, she crawled behind the living room curtains, closing herself off from us by her own initiative for the first time. The unadulterated joy on her face when she popped out the other side and saw us was almost too much to bear. Suddenly, my baby “got” peekaboo. And she loved it! As she continued to play out variations – turning her face towards the curtain, wrapping it around her – I could almost see the synapses forming. I was as overjoyed as she was. I was bearing witness to a level of integration that she had never experienced before.

It was cognitive development at its finest. But as Dani plunges down the road of advancing intellect, I am preoccupied by the urge to pause and reflect upon the “behavioral communicative system” that got us this far. Dani is still pre-verbal, but our communication is becoming ever more explicit in nature. Her vocalizations speak volumes. When she wants or likes something, she makes sounds of excitement and joy. When she needs something or is unhappy, she makes a hacking pre-cry. Her desires are so simple and present-moment oriented, that this binary communication works for us most of the time. Other times, all I have to do is follow her gaze to guess what she wants. I want to fuse into my memory all the implicit, behavior-based ways of communicating that we are still experiencing, before they are completely subsumed by the explicit world of language.

Sander was among the first to study the “implicit relational knowing” that defines communication with an infant “long before language and words are available” (Sander p29). Sander looked at films of newborns and their mothers frame by frame, and discovered an exquisitely beautiful dance that was too subtle to be noticed in real time. For example, newborn babies’ bodies actually move in synch with their mothers’ words. “The undulations of a baby’s body, in synchrony with the words ‘I love you,’ are unmistakable” (Quinn). T Berry Brazelton was also a pioneer in recognizing this amazing truth. Noting that: “It takes one second to copy someone, but mothers and babies look away and towards each other in less time than that. By 4-weeks old, they have developed ways to move in synch, like dance partners” (Brandt).

This unconscious synchronicity, this ability to move in time with the other without even knowing you have “decided” to do so, can only be explained if we think of parent and baby as subsystems – parts of a larger whole. As I explored here, this experience of wholeness in relation to the other is so beautiful, so ecstatic, it makes all the challenges of parenting an infant pale in comparison to the depth of love and joy. And it is precisely because it is unconscious that I cannot put my finger on it and hold it in place. Dani and I have simply been dancing together, wordlessly, effortlessly – her slightest shift in body posture or affect sending me a wealth of information, to which I respond without conscious thought. We have, in many ways, been interacting from “lower” parts of the brain – our limbic systems co-regulating emotions, our diencephalons co-regulating movement, our brain stems co-regulating heart rate. We have been breathing together, weaving our relationship through the “patterned repetitive somato-sensory activities” of mutual regulation. (Perry 2014) These ways of being together will not disappear as her developing cortex enables us to embark on more cognitive-centered interactions. But they will become increasingly hidden beneath the surface of words and explicit knowledge.

Of course, there is also an inherent “paradoxical tension of being together-with while at the same time being distinct-from another”. Tronick argues that the solution to this paradox lies in Brazelton’s observation: “the rhythmicity of looking and looking away” (Sander p24).  As we engage and disengage throughout the day, especially when we read each others cues and participate in contingent, attuned interactions, we can find comfort in being both together distinct at the same time. And no interaction better plays out this dynamic than the game of peekaboo.

Engagement and disengagement are natural rhythms that sustain any dyad. In all relationships, we dance between the competing needs for intimacy and space. When well matched, we synch up, and routinely meet in “states of mutual readiness.” Peekaboo replicates the engagement/disengagement process, bringing into conscious awareness these adaptive states that are otherwise “experienced in the nature of a ‘given’” (Sander p36). Baby-lead peekaboo is subtle. Because babies are not all that hidden, you have to watch closely to notice when they think they are out of sight, and when they expect to be seen. If you disengage at the wrong moment, you may find yourself saying, “there you are!” just when they are turning away from you again. When parents and infants are “fitted together well”, the attunement necessary to play together occurs naturally, both in peekaboo and unconsciously throughout the day. When they are not (because of differences in temperament, maternal depression, external stressors or other factors) life can be a series of missed opportunities and disjointed rhythms.

The “brain is always trying to make sense of the world by connecting patterns of neural activity that co-occur… making associations between sensory signals co-occurring at any moment in time” (Perry 2014). Routinely experiencing synchronicity and the joy it brings, or disconnection and the sense of isolation it engenders, will greatly influence how babies perceives themselves, and what they grow to expect from relationships. Furthermore, synchronicity is a biological adaptation as much as it is a relational one. “Synchronized rhythms of neural firing spark the anatomical connection and chemical processes necessary for perception, memory, language, and even consciousness” (Sander p25). In fact, synchronized rhythm is a universal experience, common across all of humanity, all living beings, the movements of atoms and molecules, and those of planets and galaxies.

“Life evolved in response to, and in synchronicity with, the rhythm of the days and seasons” (Perry 2013). There is an inherent drive to synchronize that appears across the realms of physics. Whether we are dancing or playing music, or simply playing a round of peekaboo, we intuitively know when we have synched up because it feels right inside. When the rhythms of moving systems share a common signal, it “amplifies the signal, increasing the inclusiveness and strength of coherence (and)… the flow of energy. This is one reason… expanding the inclusiveness of two states of consciousness as they become engaged together can be thought of as motivational” (Sander p25). In other words, when Dani and I synchronize our rhythms of interaction, both of our brains benefit, as we achieve greater complexity, coherence and integration.

Tronick points out that the brain, like all complex systems, “functions to incorporate and integrate information into increasingly coherent and complex states” (Tronick, p59). Information is the nutrient of the mind: when we are successful at gaining new information, we grow and develop. Without it, we languish and dissolve (Tronick). Since “information enters the brain most effectively through the relational context,” relationships are “the optimal mediator of all cognitive content. ” And since “we have to be regulated to fully engage in relational interactions in an optimal way,” the basic rhythms of mutual regulation are fundamental to accessing the information we need to grow and thrive (Perry 2013).

The capacity to co-create increasingly complex rhythms of relating benefits each individual and also the larger whole. Each recurrent meeting in a “state of mutual readiness” becomes another key moment “that changes organization. It is the now moment of ‘knowing and being known’…that brings coherence or wholeness to a dyadic system.” Each time we experience ourselves while experiencing the other, and relate our sense of self to our sense of the other, “is central to regulation, to adaptation, to integration.” (Sander p40-41).

Cognitive development appears, at first glance, to be the primary motivation behind peekaboo. But it is only a small segment of all that is being rehearsed and reinforced with each round of the game. Optimal cognitive development is dependent upon the synchrony of attuned primary relationships, and it is this dance that peekaboo pushes the dyad to master. Peekaboo is, above all else, an exultation of the rhythms of relating.


Brandt, K. (February 21, 2014) NCAST Feeding Scale. Lecture conducted from IPMHPCP, Napa, CA.

Perry, B. (June 21, 2013) Neurosequential Model of Therapeutics. Lecture conducted from IPMHPCP, Napa, CA.

Perry, B. (June 27-28, 2014) Neurosequential Model of Therapeutics. Lecture conducted from IPMHPCP, Napa, CA.

Quinn, Susan. “The Competence of Babies.” The Atlantic http://www.thea tlantic.com. January 1982, web: July 10, 2015.

Sander, Louis W. “Thinking Differently: Principles of the Process in Living Systems and the Specificity of Being Known.” Psychoanalytic Dialogues v12(1), 2002. pp 11-42.

Tronick, E. (January 18, 2014) Neurobehavioral & Social-Emotional Development in a Cultural Context. Lecture conducted from IPMHPCP, Napa, CA.

Tronick, Ed. “Typical and Atypical Development: Peekaboo and Blind Selection.” Infant and Early Childhood Mental Health: Core Concepts and Clinical Practice. Ed. Kristie Brandt, et.al. Washington, DC: American Psychiatric Publishing, 2014. pp 55-70


Leave a Reply

Your email address will not be published. Required fields are marked *