Robert Kegan (born 24 August 1946) is an American developmental psychologist and author. He is the William and Miriam Meehan Professor in Adult Learning and Professional Development at Harvard Graduate School of Education. Additionally he is the Educational Chair for the Institute for Management and Leadership in Education and the Co-director for the Change Leadership Group. He is a licensed psychologist and practicing therapist, lectures widely to professional and lay audiences, and consults in the area of professional development.
Education and early career
Born in Minnesota, Kegan attended Dartmouth College, graduating summa cum laude in 1968. He has described the civil rights movement and the movement against the Vietnam War as formative experiences during his college years. He took his "collection of interests in learning from a psychological and literary and philosophical point of view" to Harvard University, where he earned his Ph.D. in 1977.
The Evolving Self
In his book The Evolving Self (1982), Kegan explores human life problems from the perspective of a single process which he calls meaning-making, the activity of making sense of experience through discovering and resolving problems. "Thus it is not that a person makes meaning, as much as that activity of being a person is the activity of meaning-making," Kegan says. Meaning-making is a lifelong activity that begins in earliest infancy and can evolve in complexity through a series of "evolutionary truces" (or "evolutionary balances") that establish a balance between self and other (in psychological terms), or subject and object (in philosophical terms), or organism and environment (in biological terms). Each evolutionary truce is both an achievement of and a constraint on our meaning-making, possessing both strengths and limitations. And each evolutionary truce presents a new solution to the lifelong tension between how people are connected, attached, and included, on the one hand (integration), and how people are distinct, independent, and autonomous on the other (differentiation).
The purpose of the book is primarily to give professional helpers (such as counselors, psychotherapists, and coaches) a broad framework for empathizing with their clients' different ways of making sense of their problems. Kegan adapts Donald Winnicott's idea of the holding environment and proposes that the evolution of meaning-making is a life history of holding environments, or cultures of embeddedness. Kegan describes cultures of embeddedness in terms of three processes: confirmation (holding on), contradiction (letting go), and continuity (staying put for reintegration). For Kegan, "the person is more than an individual," and developmental psychology is the study of the evolution of cultures of embeddedness, not the study of isolated individuals. "One of the most powerful features of this psychology, in fact, is its capacity to liberate psychological theory from the study of the decontextualized individual. Constructive-developmental psychology reconceives the whole question of the relationship between the individual and the social by reminding that the distinction is not absolute, that development is intrinsically about the continual settling and resettling of this very distinction." Kegan shows how some of the psychological distress that people experience (including some depression) can be thought of as a result of the "natural emergencies" that happen when "the terms of our evolutionary truce must be renegotiated" and a new culture of embeddedness must emerge.
The Evolving Self is notable for its theoretical integration of three very different intellectual traditions. The first is the humanistic and existential-phenomenological tradition (which includes Martin Buber, Prescott Lecky, Abraham Maslow, Rollo May, Ludwig Binswanger, Andras Angyal, and Carl Rogers). The second is the neo-psychoanalytic tradition (which includes Anna Freud, Erik Erikson, Ronald Fairbairn, Donald Winnicott, Margaret Mahler, Harry Guntrip, John Bowlby, and Heinz Kohut). The third is what Kegan calls the constructive-developmental tradition (which includes James Mark Baldwin, John Dewey, George Herbert Mead, Jean Piaget, Lawrence Kohlberg, and Jane Loevinger). The book is also strongly influenced by dialectical philosophy and psychology and by Carol Gilligan's psychology of women. Despite the book's wealth of human stories, due to the density of Kegan's writing and its conceptual complexity, some readers have found it difficult to read.
Kegan presents a sequence of six evolutionary balances: incorporative, impulsive, imperial, interpersonal, institutional, and interindividual. The following table is a composite of several tables in The Evolving Self that summarize these balances. The object (O) of each balance is the subject (S) of the preceding balance. The process of emergence of each evolutionary balance is described in detail in the text of the book; as Kegan says, his primary interest is the ontogeny of these balances, not just their taxonomy.
|Evolutionary balance||Culture of embeddedness||Analogue in Piaget||Analogue in Kohlberg||Analogue in Loevinger||Analogue in Maslow||Analogue in McClelland/Murray||Analogue in Erikson|
||Mothering culture. Mothering one(s) or primary caretaker(s).||Sensorimotor||—||Pre-social||Physiological survival orientation||—||—|
||Parenting culture. Typically, the family triangle.||Preoperational||Punishment and obedience orientation||Impulsive||Physiological satisfaction orientation||—||Initiative vs. guilt|
||Role-recognizing culture. School and family as institutions of authority and role differentiation. Peer gang which requires role-taking.||Concrete operational||Instrumental orientation||Opportunistic||Safety orientation||Power orientation||Industry vs. inferiority|
||Culture of mutuality. Mutually reciprocal one-to-one relationships.||Early formal operational||Interpersonal concordance orientation||Conformist||Love, affection, belongingness orientation||Affiliation orientation||(Affiliation vs. abandonment?)|
||Culture of identity or self-authorship (in love or work). Typically: group involvement in career, admission to public arena.||Full formal operational||Societal orientation||Conscientious||Esteem and self-esteem orientation||Achievement orientation||Identity vs. identity diffusion|
||Culture of intimacy (in love and work). Typically: genuinely adult love relationship.||(Post-formal; Dialectical?)||Principled orientation||Autonomous||Self-actualization||(Intimacy orientation?)||—|
The final chapter of The Evolving Self, titled "Natural Therapy," is a meditation on the philosophical and ethical fundamentals of the helping professions. Kegan argues, similarly to later theorists of asset-based community development, that professional helpers should base their practice on people's existing strengths and "natural" capabilities. The careful practice of "unnatural" (self-conscious) professional intervention may be important and valuable, says Kegan; nevertheless "rather than being the panacea for modern maladies, it is actually a second-best means of support, and arguably a sign that the natural facilitation of development has somehow and for some reason broken down." Helping professionals need a way of evaluating the quality of people's evolving cultures of embeddedness so as to provide opportunities for problem-solving and growth, while acknowledging that the evaluator too has his or her own evolving culture of embeddedness. Kegan warns that professional helpers should not delude themselves into thinking that their conceptions of health and development are unbiased by their particular circumstances or partialities. He acknowledges the importance of Thomas Szasz's "suggestion that mental illness is a kind of myth," and he says that we need a way to address what Szasz calls "problems in living" while protecting clients as much as possible from the helping professional's partialities and limitations.
In Over Our Heads
Kegan's book In Over Our Heads (1994) extends the perspective on psychological development formulated in his earlier book The Evolving Self. What Kegan earlier called "evolutionary truces" of increasing subject–object complexity are now called "orders of consciousness." In Over Our Heads explores what happens, and how people feel, when new orders of consciousness emerge, or fail to emerge, in the domains of parenting (families), partnering (couples), working (companies), healing (psychotherapies), and learning (schools). Kegan repeatedly points to the suffering that can result when people are presented with challenging tasks and expectations without the necessary support to master them.
In addition, Kegan now distinguishes between orders of consciousness (cognitive complexity) and styles (stylistic diversity). Theories of style describe "preferences about the way we know, rather than competencies or capacities in our knowing, as is the case with subject–object principles." Kegan's writing in this book continues the same combination of detailed storytelling and theoretical analysis found in his earlier book, but now he presents a "more complex bi-theoretical approach" rather than the single subject–object theory he presented in The Evolving Self.
The following table is a composite of several tables from In Over Our Heads that summarizes the orders of consciousness explored in the book, with the domain of learning history as an example. The object (O) of each order of consciousness is the subject (S) of the preceding order.
|Order of consciousness||Cognitive development||Interpersonal development||Intrapersonal development||Curricular form (using History as an example)||Appropriate audience for curricular form||Structure|
||The story of history. The concrete facts and the narrative line (e.g., the "story" of "settling the West" or "how the world went to war")||School children. Grades 1–3 (a stretch), grades 4–6 (elaborating an emerging capacity)||durable categories|
||Elementary historiography. How history is written; its dependence on the perspective of the historian; the themes and values expressed in "a history" of given events||Adolescents. Junior high students (a stretch), high school students (elaborating an emerging capacity)||cross-categorical structures|
||Historical theory. The discipline's system or systems for creating historical knowledge, generating, regarding, evaluating, and relating inferences||Adults. Any higher education setting (a stretch for many)||systems|
||Critical theory. Critical reflection on the discipline itself; subjecting its prevailing theories to analysis not just from the perspective of another contending theory but from a perspective "outside ideology"||Adults. Any higher education setting (a stretch for most); graduate programs in history and within the history profession itself (a stretch for many)||trans-system structures|
In the last chapter of In Over Our Heads, titled "On Being Good Company for the Wrong Journey," Kegan warns that it is easy to misconceive the nature of the mental transformation that a person needs or seeks to make. Whatever the virtues of higher orders of consciousness, no one should expect us to master them when we are not ready or when we are without the necessary support; and we are unlikely to be helped by someone who assumes that we are engaged at a certain order of consciousness when we are not. He ends the book with a paean to passionate engagement and to the creative unpredictability of human lives.
Immunity to Change
Kegan's next book, How the Way We Talk Can Change the Way We Work (2001), co-authored with Lisa Laskow Lahey, jettisons the theoretical framework of his earlier books The Evolving Self and In Over Our Heads and instead presents a practical method, called the immunity map, intended to help readers overcome an immunity to change. An immunity to change is our "processes of dynamic equilibrium, which, like an immune system, powerfully and mysteriously tend to keep things pretty much as they are."
The immunity map continues the general dialectical pattern of Kegan's earlier thinking but without any explicit use of the concept of "evolutionary truces" or "orders of consciousness." The map primarily consists of a four-column worksheet that is gradually filled in by individuals or groups of people during a structured process of self-reflective inquiry that involves asking questions such as: What are the changes that we think we need to make? What are we doing or not doing to prevent ourselves (immunize ourselves) from making those changes? What anxieties and big assumptions does that doing or not doing imply? How can we test those big assumptions so as to disturb our immunity to change and make possible new learning and change? The following table presents an example of an immunity map.
|1. Commitment: I am committed to the value or the importance of...||2. What I'm doing or not doing that prevents my commitment from being fully realized||3. Competing commitment: I may also be committed to...||4. Big assumption: I assume that if...|
|Supporting my staff to exercise more individual initiative.||When they ask me to get involved or take over, I don't refuse. I don't delegate as much as I could. I too often am willing to be drawn into things when I should refer to the subordinate who is in charge of that area.||Not having my staff feel like I've abandoned them; not having my staff unhappy with me; not having our work product be less than I think I could do on my own, even if it means disempowering or failing to empower my staff.||The quality of our work, when I transfer authority, does fall below what I could produce by maintaining more control, then I will be seen as a failure.|
In How the Way We Talk Can Change the Way We Work, Kegan and Lahey progressively introduce each of the four columns of the immunity map in four chapters that show how to transform people's way of talking to themselves and others. In each case, the transformation in people's way of talking is a shift from a habitual and unreflective pattern to a more deliberate and self-reflective pattern. The four transformations, each of which corresponds to a column of the immunity map, are:
- From the language of complaint to the language of commitment
- From the language of blame to the language of personal responsibility
- From the language of New Year's resolutions to the language of competing commitments
- From the language of big assumptions that hold us to the language of assumptions we hold
In three subsequent chapters, Kegan and Lahey present three transformations that groups of people can make in their social behavior, again from a lesser to greater self-reflective pattern:
- From the language of prizes and praising to the language of ongoing regard
- From the language of rules and policies to the language of public agreement
- From the language of constructive criticism to the language of deconstructive criticism
Immunity to Change (2009), the next book by Kegan and Lahey, revisits the immunity map of their previous book. The authors describe three dimensions of immunity to change: the change-preventing system (thwarting challenging aspirations), the feeling system (managing anxiety), and the knowing system (organizing reality). They further illustrate their method with a number of actual case studies from their experiences as consultants, and they connect the method to a dialectic of three mindsets, called socialized mind, self-authoring mind, and self-transforming mind. (These correspond to three of the "evolutionary truces" or "orders of consciousness" in Kegan's earlier books.) Kegan and Lahey also borrow and incorporate some frameworks and methods from other thinkers, including Ronald A. Heifetz's distinction between technical and adaptive learning, Chris Argyris's ladder of inference, and the four stages of competence. They also provide more detailed guidance on how to test big assumptions.
The revised immunity map worksheet in Immunity to Change has the following structure: (0) Generating ideas. (1) Commitment (improvement) goals. (2) Doing / not doing. (3) Hidden competing commitment (and worry box). (4) Big assumption. (5) First S-M-A-R-T test: Safe, Modest, Actionable, Research stance (not a self-improvement stance), Test.
Adult education professor Ann K. Brooks has criticized Kegan's book In Over Our Heads. She claims that Kegan falls victim to a cultural "myopia" that "perfectly reflects the rationalist values of modern academia." Brooks also says that Kegan excludes "the possibility of a developmental trajectory aimed at increased connection with others," which is contradicted by Ruthellen Josselson's statement that Kegan "has made the most heroic efforts" to balance individuality and connection with others in his work.
- Kegan, Robert; Lahey, Lisa Laskow (2009). Immunity to change: how to overcome it and unlock potential in yourself and your organization. Boston: Harvard Business Press. ISBN 078796378X. OCLC 44972130.
- Wagner, Tony; Kegan, Robert (2006). Change leadership: a practical guide to transforming our schools. San Francisco: Jossey-Bass. ISBN 0787977551. OCLC 61748276.
- Kegan, Robert; Lahey, Lisa Laskow (2001). How the way we talk can change the way we work: seven languages for transformation. San Francisco: Jossey-Bass. ISBN 078796378X. OCLC 44972130.
- Kegan, Robert (1994). In over our heads: the mental demands of modern life. Cambridge, MA: Harvard University Press. ISBN 0674445880. OCLC 29565488.
- Kegan, Robert (1982). The evolving self: problem and process in human development. Cambridge, MA: Harvard University Press. ISBN 0674272315. OCLC 7672087.
- Kegan, Robert (1976). The sweeter welcome: voices for a vision of affirmation—Bellow, Malamud, and Martin Buber. Needham Heights, MA: Humanitas Press. ISBN 0911628258. OCLC 2952603.
- HGSE 2006
- Scharmer & Kegan 2000
- Kegan 1982, pp. 11
- Kegan 1982, pp. 28
- Kegan 1982, pp. 30
- Kegan 1982, pp. 3; Scharmer & Kegan 2000
- Kegan 1982, pp. 118
- Kegan 1982, pp. 116
- Kegan 1982, pp. 115
- Kegan 1982, pp. 110
- Kegan 1982, pp. 3–4; Scharmer & Kegan 2000
- Kegan cites the dialectical psychology of Michael Basseches, and Basseches in turn was influenced by Kegan. See Basseches 1984 and Basseches & Mascolo 2009.
- Kegan 1994, pp. 2
- Kegan 1982, pp. 114; Kegan, Lahey & Souvaine 1998
- Kegan 1982, pp. 256
- Kegan 1982, pp. 291
- Csikszentmihalyi 2003, pp. 32; Heifetz 1994, pp. 288, 310; Josselson 1992, pp. 276; Vaillant 1993, pp. 365, 370
- Kegan 1994
- Kegan 1994, pp. 201
- Kegan 1994, pp. 203
- Kegan 1994, pp. 351
- Deutsch 2005, pp. 11; Heron & Reason 1997, pp. 283; Kolb & Kolb 2005, pp. 207; Mezirow 2000, pp. 11, 26
- Kegan & Lahey 2001
- Kegan & Lahey 2001, pp. 5
- Kegan & Lahey 2001, pp. 78
- Kegan & Lahey 2009
- Kegan & Lahey 2009, pp. 280
- Argyris 2010; Gergen 2009, pp. 314; Kets de Vries 2011, pp. 178, 273; Schwartz, Gomes & McCarthy 2010
- Brooks 2000, pp. 161–162
- Brooks 2000, pp. 162
- Josselson 1992, pp. 264
- Argyris, Chris (2010). Organizational traps: leadership, culture, organizational design. Oxford; New York: Oxford University Press. ISBN 0199586160. OCLC 477256777.
- Basseches, Michael (1984). Dialectical thinking and adult development. Norwood, NJ: Ablex. ISBN 0893910171. OCLC 10532903.
- Basseches, Michael; Mascolo, Michael F (2009). Psychotherapy as a developmental process. New York: Routledge. ISBN 0805857303. OCLC 244063508.
- Brooks, Ann K (2000). "Cultures of transformation". In Wilson, Arthur L; Hayes, Elisabeth. Handbook of adult and continuing education (2nd ed.). San Francisco: Jossey-Bass. pp. 161–170. ISBN 0787949981. OCLC 43945222.
- Csikszentmihalyi, Mihaly (2003). Good business: leadership, flow, and the making of meaning. New York: Viking. ISBN 0670031968. OCLC 51963359.
- Deutsch, Morton (2005). "Cooperation and conflict: a personal perspective on the history of the social psychological study of conflict resolution". In West, Michael A; Tjosvold, Dean; Smith, Ken G. The essentials of teamworking: international perspectives. Chichester, England; Hoboken, NJ: Wiley. pp. 1–36. ISBN 0470015489. OCLC 57527156.
- Gergen, Kenneth J (2009). Relational being: beyond self and community. Oxford; New York: Oxford University Press. ISBN 0195305388. OCLC 258329308.
- Heifetz, Ronald A (1994). Leadership without easy answers. Cambridge, MA: Belknap Press of Harvard University Press. ISBN 0674518586. OCLC 30319597.
- Heron, John; Reason, Peter (September 1997). "A participatory inquiry paradigm". Qualitative Inquiry 3 (3): 274–294. doi:10.1177/107780049700300302.
- Josselson, Ruthellen (1992). The space between us: exploring the dimensions of human relationships. San Francisco: Jossey-Bass. ISBN 1555424104. OCLC 24796594.
- Kegan, Robert; Lahey, Lisa Laskow; Souvaine, Emily (1998). "From taxonomy to ontogeny: thoughts on Loevinger's theory in relation to subject–object psychology". In Westenberg, P Michiel; Blasi, Augusto; Cohn, Lawrence. Personality development: theoretical, empirical, and clinical investigations of Loevinger's conception of ego development. Mahwah, NJ: Lawrence Erlbaum Associates. pp. 39–58. ISBN 0805816496. OCLC 37725587.
- Kets de Vries, Manfred F R (2011). The hedgehog effect: executive coaching and the secrets of building high performance teams. San Francisco: Jossey-Bass. ISBN 1119973368. OCLC 741542278.
- Kolb, Alice Y; Kolb, David A (June 2005). "Learning styles and learning spaces: enhancing experiential learning in higher education". Academy of Management Learning & Education 4 (2): 193–212. doi:10.5465/AMLE.2005.17268566.
- Mezirow, Jack (2000). "Learning to think like an adult: core concepts of transformation theory". In Mezirow, Jack. Learning as transformation: critical perspectives on a theory in progress. Jossey-Bass higher and adult education series. San Francisco: Jossey-Bass. pp. 3–34. ISBN 0787948454. OCLC 43913070.
- Scharmer, Claus Otto; Kegan, Robert (23 March 2000). "Grabbing the tiger by the tail: interview with Robert Kegan". Dialogue on Leadership, Presencing Institute. Retrieved 19 May 2013.
- Schwartz, Tony; Gomes, Jean; McCarthy, Catherine (2010). The way we're working isn't working: the four forgotten needs that energize great performance. New York: Free Press. ISBN 1439127662. OCLC 310397922.
- Vaillant, George E (1993). The wisdom of the ego. Cambridge, MA: Harvard University Press. ISBN 067495372X. OCLC 26856357.
- Bachkirova, Tatiana; Kegan, Robert (March 2009). "Cognitive-developmental approach to coaching: an interview with Robert Kegan". Coaching: An International Journal of Theory, Research and Practice 2 (1): 10–22. doi:10.1080/17521880802645951.
- Berger, Jennifer Garvey (2012). Changing on the job: developing leaders for a complex world. Stanford, CA: Stanford Business Books, an imprint of Stanford University Press. ISBN 080477823X. OCLC 726818986.
- Bochman, David J; Kroth, Michael (2010). "Immunity to transformational learning and change". The Learning Organization: An International Journal 17 (4): 328–342. doi:10.1108/09696471011043090.
- Demick, Jack; Andreoletti, Carrie, eds. (2003). Handbook of adult development. Plenum series in adult development and aging. New York: Kluwer Academic/Plenum. ISBN 0306467585. OCLC 49519013.
- Eriksen, Karen; Kegan, Robert (2006). "Robert Kegan, PhD: subject–object theory and family therapy". The Family Journal 14 (3): 299–305. doi:10.1177/1066480706287795.
- Helsing, Deborah; Howell, Annie; Kegan, Robert; Lahey, Lisa Laskow (Fall 2008). "Putting the 'development' in professional development: understanding and overturning educational leaders' immunities to change". Harvard Educational Review 78 (3): 437–465.
- Hoare, Carol Hren, ed. (2006). Handbook of adult development and learning. Oxford; New York: Oxford University Press. ISBN 019517190X. OCLC 60543390.
- Kaiser, Robert B; Kaplan, Robert E (December 2006). "The deeper work of executive development: outgrowing sensitivities". Academy of Management Learning and Education 5 (4): 463–483. doi:10.5465/AMLE.2006.23473207.
- Kegan, Robert (1980). "There the dance is: religious dimensions of a developmental framework". In Brusselmans, Christiane; O'Donohoe, James A; Fowler, James W; Vergote, Antoine. Toward moral and religious maturity. International Conference on Moral and Religious Development. Morristown, NJ: Silver Burdett Co. pp. 403–440. ISBN 0382002865. OCLC 6468267.
- Kegan, Robert (1998). "Epistemology, expectation, and aging: a developmental analysis of the gerontological curriculum". In Lomranz, Jacob. Handbook of aging and mental health: an integrative approach. Plenum series in adult development and aging. New York: Plenum Press. pp. 197–216. ISBN 0306457504. OCLC 39381280.
- Kegan, Robert (2000). "What 'form' transforms?: a constructive-developmental approach to transformative learning". In Mezirow, Jack. Learning as transformation: critical perspectives on a theory in progress. Jossey-Bass higher and adult education series. San Francisco: Jossey-Bass. pp. 35–70. ISBN 0787948454. OCLC 43913070.
- Kegan, Robert (2001). "Easing a world of pain: learning disabilities and the psychology of self-understanding". In Rodis, Pano; Garrod, Andrew; Boscardin, Mary Lynn. Learning disabilities and life stories. Boston: Allyn & Bacon. pp. 194–204. ISBN 0205320104. OCLC 43083301.
- Kegan, Robert; Lahey, Lisa Laskow (1984). "Adult leadership and adult development: a constructionist view". In Kellerman, Barbara. Leadership: multidisciplinary perspectives. Englewood Cliffs, NJ: Prentice-Hall. pp. 199–230. ISBN 0135276713. OCLC 9682350.
- Kegan, Robert; Lahey, Lisa Laskow (2010). "From subject to object: a constructive-developmental approach to reflective practice". In Lyons, Nona. Handbook of reflection and reflective inquiry: mapping a way of knowing for professional reflective inquiry. New York: Springer. pp. 433–449. doi:10.1007/978-0-387-85744-2_22. ISBN 0387857443. OCLC 663096444.
- Lahey, Lisa Laskow; Souvaine, Emily; Kegan, Robert; Goodman, Robert; Felix, Sally (1988). A guide to the subject–object interview: its administration and interpretation. Cambridge, MA: The Subject–Object Research Group, Laboratory of Human Development, Harvard Graduate School of Education. OCLC 31995875.
- McAuliffe, Garrett J; Eriksen, Karen, eds. (2011). Handbook of counselor preparation: constructivist, developmental, and experiential approaches. Published in cooperation with the Association for Counselor Education and Supervision (ACES). Thousand Oaks, CA: Sage Publications. ISBN 1412991773. OCLC 641528454.
- Rogers, Laura; Kegan, Robert (1991). "'Mental growth' and 'mental health' as distinct concepts in the study of developmental psychopathology: theory, research, and clinical implications". In Keating, Daniel P; Rosen, Hugh. Constructivist perspectives on developmental psychopathology and atypical development. Hillsdale, NJ: Lawrence Erlbaum Associates. pp. 103–148. ISBN 0805804374. OCLC 20934662.
- Silver, Junell; Josselson, Ruthellen (2010). "Epistemological lenses and group relations learning". Organisational and Social Dynamics: An International Journal of Psychoanalytic, Systemic and Group Relations Perspectives 10 (2): 155–179.
- Torbert, William R (2004). Action inquiry: the secret of timely and transforming leadership. San Francisco: Berrett-Koehler. ISBN 157675264X. OCLC 53793296.
- "Directory of People & Offices: Robert Kegan". Harvard Graduate School of Education. 2006. Retrieved 19 May 2013.
- "Minds at Work". Consulting group co-founded by Robert Kegan and Lisa Laskow Lahey. 2001. Retrieved 19 May 2013.