Louis Cozolino

The Neuroscience of Human Relationships:

Attachment and the Developing Social Brain

W. W. Norton & Co., New York, 2006, 447 pp

Book Review By Dennis Miehls

Smith College School of Social Work, Northampton, MA 01603, USA

In this text, Louis Cozolino adds to his impressive contributions to the increasingly important and relevant field of neurobiology and attachment theory, and how these contribute to human development. His 2002 text, The neuroscience of psychotherapy: Building and rebuilding the human brain , set some of the conceptual framework for his current endeavor. In his current text, Cozolino explicitly explores how our human interpersonal interactions fundamentally shape the construction of each other’s brains. He notes that the brain is an organ of adaptation and that its structures are built in interaction with others. He emphasizes the notion that ‘‘there are no single brains’’ (p. 6) and in so doing, he clearly positions attachment constructs and relationships at the heart of the development of both adaptive and maladaptive behaviors in children and adults. His thesis challenges the Western construct of individualism. Rather than honoring the notion that ‘‘healthy’’ individuals are autonomous, independenceseeking creatures, he suggests that one’s social brain, with its’ many potentialities, is fundamentally shaped in interaction with other people. As such, healthy individuals rely on others throughout the lifespan to change and develop their strengths and capacities. This idea is consistent with a number of current psychological theories including relational theory (Mitchell 1988 , 1997 ; Mitchell and Black 1995 ), intersubjective theory (Mitchell 2000 ), and attachment theory (Milulincer and Shaver 2007 ; Schore 2000 ), all which emphasize the crucial nature of mutuality in growth enhancing relational endeavors.

Increasingly, authors explore the interface of attachment theory, developmental psychology, cognitive neuroscience, neurobiology, and clinical practice (Applegate and Shapiro 2005 ) and Cozolino’s text adds to this growing literature. The text is organized in six sections: (1) The emergence of social neuroscience; (2) the social brain: structures and functions; (3) bridging the social synapse; (4) social vision: the language of faces; (5) disorders of the social brain; and (6) social neural plasticity. Each section of the text offers rich and highly specific conceptual data about social brain functioning. An ambitious reader can integrate a sophisticated understanding of brain physiology. However, another reader who may not want to fully integrate the specificity of all aspects of brain functioning, can still glean much useful conceptual and clinical information. The text offers excellent tables and figures that deconstruct complex ideas in a user-friendly manner. Cozolino also illustrates the concepts with many clinical examples, interspersed throughout the text.

The first two sections of the book lay out the conceptual framework of the text. Cozolino encourages the reader to ‘‘relax’’ with the material and to recognize that he will re-visit essential constructs throughout the text. He notes ‘‘The complexity of the brain makes any exploration simultaneously detail-rich and miserably incomplete’’ (pp. 50–51). Not surprisingly, he talks about the positive benefits of healthy relationships and he discusses how optimal sculpting of the prefrontal cortex shapes our sense of ourselves, our trust in others, our intellectual and emotional intelligence, and our ability to regulate our emotions, among other effects. He explores the differences of right and left hemisphere brain development, and he notes that right brain development precedes left-brain development. Hence, the right brain is more closely aligned with unconscious processes that assess safety and danger, in situations and relationships. Cozolino emphasizes that the brain is a living system and that plasticity occurs throughout the life cycle. He notes how particularly active the teenage brain is, and he suggests that major reorganization of the social brain happens from puberty to the early 20s. In addition, he notes that older adults are often considered wise as a result of their ability to utilize the strengths of both right and left-brain hemispheres.

Cozolino says that seeing the brain as a social organ requires the student to engage in some conceptual shifts. For example, important cortical areas are no longer those on the surface of the brain, but those hidden from view. Also important, he notes that the right side of the brain is the dominant hemisphere responsible for social and emotional functioning (the left hemisphere is responsible for language development and has often been thought of as more important than right hemisphere functions in terms of emotional functioning). Since the right hemisphere develops first, it stores and organizes early experiences. The right hemisphere, then, is most illustrative of Freud’s concepts of the unconscious and primary process. This implies that the influence of the right hemisphere emerges later in relationships, especially when an individual experiences stress. Countless interactions with others shape our right brain in ways that affect ‘‘our subsequent responses to others, our sense of safety and danger, and our ability to regulate our emotions’’ (p. 70). Damage to right brain circuitry compromises one’s ability to read such things as facial expressions, hand gestures, or tone of voice. Optimally, right and left brain circuitry develop in a recursive, reciprocal manner and the individual is able to rely on the capacities of each to appraise others in his or her environment. He notes ‘‘When conditions are right, all of these networks integrate to provide us with the experience of a safe, coherent, and livable inner world’’ (p. 73).

In part 3 of the book, Bridging the Social Synapse, Cozolino fully expands his thinking about the central function of attachment in optimal development. Not only does he give a summary of the development of attachment theory (Chapter 10), he also explains the ‘‘Polyvagal Theory of Social Engagement’’ which allows individuals to seek closeness to others without activating fight/flight responses. He notes that good vagal regulation in adults allows one to become angry, upset or anxious with a loved one without withdrawing or becoming physically aggressive. He reinforces the now widely held view that infants come ready to participate in relationships at birth and that the cingulate cortex (regulating smell, sound, sight, and touch) is a vital structure of the social brain—once again, emphasizing the importance of the attachment relationship in healthy development. He fully articulates the development of explicit and implicit memory and he aptly describes that the vast majority of memory is implicit and that this memory again fundamentally shapes our emotional experiences, self-image, and relationships.

Though Cozolino gives clinical examples throughout, the fifth section of the book, Disorders of the Social Brain, elucidates his conceptual framework when he talks about the impact of early stress on brain development. He devotes a chapter to interpersonal trauma, and he fully describes the impact of abuse on child development and brain physiology. He makes a direct link to how abused children experience profound shame. I found this to be a highly relevant section for clinical practice. Equally important, he discusses social phobia (when others trigger fear responses). In this chapter, he elaborates the function of the amygdala in the evaluation of fear and safety. A chapter devoted to failed attachment leads him to discuss the interpersonal and intrapersonal experience of those clients typically diagnosed with Borderline Personality— again, a highly relevant clinical article. He devotes chapters to both antisocial individuals and those individuals who experience some form of childhood or adult autism.

The last section of the book is exemplary in that Cozolino offers myriad ways of making the concepts of his book operational, including psychotherapy. Staying with his discourse that human evolution selected bonding, attachment and care taking as the vehicles to build larger, more complex and more experience-dependent social brains, he emphasizes that individuals are inseparable from the group, and that one lives in a field of mutual, interpersonal regulation. He suggests that educators and therapists need to consider new ways of interacting that account for the social embededness of human experience. He notes: ‘‘human brains have vulnerabilities and weaknesses that only other brains are capable of mending’’ (p. 307). Since the brain is an organ of adaptation, there is reason to believe that one can change brain circuitry through relationships. Psychotherapy can offer an environment and relationship that facilitates change in brain circuitry. He notes how neuroscience might enhance therapy efforts by (1) utilizing multiple means of influencing the brain; (2) selecting and combining different treatments for particular clients; (3) educating our clients about brain functions; (4) encouraging the rewriting of self-narrative by recognizing the malleability of memory; and by (5) emphasizing optimism and growth as possible outcomes of satisfying relationships.

Cozolino does give an optimistic valence to his material when he notes that there is the potential for healing relationships in many environments (teachers, coaches, ministers, and friends). However, his view is not naı¨ve in that he also explicates that evolution appears far more interested in keeping us alive than making us happy. He explains that elements of fear conditioning are powerful and that ‘‘overall, negative emotions trump positive ones and weigh more heavily in our evaluation of people and situations’’ (p. 318). He notes that the amygdala (that part of our brain that gets activated in fear situations) is ‘‘quick to learn and slow to forget’’ (p. 318). Thus, stress triggers these early responses. If one can utilize anxiety as a sign that makes us want to approach a situation—to not avoid— one can offer the hippocampus an opportunity to remodel one’s view of what constitutes threat and danger.

In summary, this text richly explores the benefits of secure attachments on the developing social brain. He offers extensive research findings and translates this material into implications for growth, development, and interventions. As noted above, readers can utilize this text as an excellent resource about brain physiology. In addition, the translation of the concepts into implications for psychotherapy is elucidated. This text does not offer a complete way of understanding human behavior. However, the concepts are highly compatible with other theories such as object relations theory and trauma theory. While I was reading the text, I often found myself comparing Cozolino’s concepts with other dynamic theories and as mentioned, the conceptual frames often gelled. As a social work academic/practitioner, I measure the utility of my reading in two broad ways: (1) will these ideas be additive to my teaching human development courses to graduate students? and (2) will these ideas be useful in my psychotherapy with clients? The answer is affirmative in each instance and I certainly recommend this text to others who are interested in furthering their knowledge about brain physiology and attachment constructs.


Applegate, J., & Shapiro, J. (2005). Neurobiology for clinical social work: theory and practice. New York: W.W. Norton & Co.
Milulincer, M., & Shaver, P. (2007). Attachment in adulthood: Structure, dynamics and change. New York: Guilford
Mitchell, S. (1988). Relational concepts in psychoanalysis. Cambridge, MA: Harvard University Press.
Mitchell, S. (1997). Influence and autonomy in psychoanalysis.
Hillsdale, NJ: The Analytic Press.
Mitchell, S. (2000). Relationality: From attachment to intersubjectivity.
Hillsdale, NJ: The Analytic Press.
Mitchell, S., & Black, M. (1995). Freud and beyond. New York: Basic Books.
Schore, A. (2000). Attachment and the regulation of the right brain. Attachment and human development, 2(1), 23–47.

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