Evolution and the Capacity for Commitment

Edited by Randolph M. Nesse

Russell Sage Press, New York, 2001

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Interview on NPR, Todd Mundt show (middle third of the show)


Commitment is at the core of social life. We live in a social fabric woven from a warp of promises and a weft of threats, and we spend much of our lives deciding which commitments are credible, and trying to manage our own commitments and reputations. Classical economics and sociobiology sometimes seem to suggest that this should not be too hard, because people should generally act in ways that benefit themselves or their genes. While reciprocity and kin selection are indeed powerful principles, attempts to force all behavior into their Procrustean bed have aroused much intellectual consternation and moral indignation. This conflict has deepened the rift between biological and social sciences. Commitment offers a bridge across this chasm. In this book, some of the world's most distinguished researchers examine the nature of commitment, and the question of whether our capacities for making, assessing and keeping commitments have been shaped by natural selection. Many commitments are fairly straightforward attempts influence others by giving up options and thereby making it worthwhile to fulfill the commitment. Examples include burning your bridges behind you or signing a contract. However many commitments are not enforced by such tangible incentives. These subjective commitments are enforced by pledges of reputation and by emotions. Some are benevolent, such as a promise of life-long love. Others are not, such as a threat to murder a straying spouse. Although some such commitments may seem irrational in the extreme, they nonetheless influence us. Commitment thus offers a possible evolutionary explanation for irrational passions that are otherwise difficult to explain, and for our moral capacities.


Foreward--Herbert Gintis

Introduction and Overview

1. The Evolution of Subjective Commitment-Randolph M. Nesse

Section I-Core ideas from Economics

2. Commitment: Deliberate vs. Voluntary-Thomas C. Schelling

3. Cooperation through Emotional Commitment -Robert Frank

4. Game-theoretic Interpretations of Commitment-Jack Hirshleifer

Section II-Commitment in Animals

5. Threat displays in animal communication: handicaps, reliability, and commitments-Eldridge S. Adams

6. Subjective commitment in non-humans: What should we be looking for, and where should be looking?-Lee Alan Dugatkin

7. Grunt, Girneys and good Intentions: The Origins of Commitment in Nonhuman Primates-Joan B. Silk Section

III-Commitment in Humans

8. Honor and faking "honorability"-Dov Cohen and Joe Vandello

9. The Biology of Commitment to Groups: A Tribal Instincts Hypothesis-Peter Richerson and Robert Boyd

10. Morality and Commitment-Michael Ruse

Section IV-Commitment in Social Organizations: Law, Psychiatry and Religion

11. Commitment in the Clinic-Randolph M. Nesse

12. Law and the Biology of Commitment-Oliver R. Goodenough 13. Religion as Commitment-William Irons


14. The Future of Commitment-Randolph M. Nesse


Commitment is a powerful social strategy whose pervasiveness is often not recognized, perhaps because it is somewhat paradoxical. Commitments involve giving up options in order to influence others. Some, such as burning your bridges behind you or signing a contract, change incentives in ways that make fulfilling the commitment advantageous. Other commitments are enforced by more intangible factors such as reputation and emotion. Such subjective commitments are commonplace, but it is hard to understand why people believe them. This book brings together 12 distinguished researchers from economics, ethology, psychology, anthropology, philosophy, medicine and law to examine the nature of commitment in unprecedented detail. They address the question of whether our capacities for commitments have been shaped by natural selection. They find examples of commitment everywhere in human social life, and they describe how social selection may have shaped specialized mental mechanisms for making and assessing subjective commitments. These mechanisms may help to account for emotional behavior that otherwise seems irrational, and perhaps also for our capacity for genuine morality. They may also offer a bridge across the rift between biological and social approaches to human nature.


"If the genes of the self-serving are more likely to be perpetuated in succeeding generations, how it is that so many of us forgo self-interest in order to honor our commitments, devote large parts of our lives to the quest for knowledge, defending animal rights, human rights, or remaining true to a cause past reason? We humans routinely behave better than conventional evolutionary theory predicts we should. Evolution and the Capacity for Commitment resolves this paradox and in doing so, extends sociobiological theory to more fully encompass idiosyncrasies of the human heart. This is a revelatory book that carries us beyond premature conclusion about innate selfishness that, if accepted, erode human relationships based on any other premise. Any one looking for a rigorous alternative to Darwin's 'universal acid,' should read this book

---Sarah Blaffer Hrdy


"This is a very valuable contribution to our understanding of commitment which no serious student of the subject will wish to miss" 

---Robert Trivers


"Nothing is more basic to the human condition than the capacity for commitment, and nothing is more important to the capacity than its biological underpinnings and evolution. Randolph Nesse, serving as editor and connecting essayist, and the other authors of Evolution and the Capacity for Commitment are among the leaders in and around this newly emerging field of scholarship."

---Edward O. Wilson


"In the 1970s, the word 'selfish' as kidnapped from common language to be applied to genes. This metaphor, however, did not say much about human psychology. Exploring the emotional make up of our species while firmly staying within an evolutionary framework, the volume spells out better than any before what is wrong with a narrow focus on human selfishness"

---Frans deWaal

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Link to Russell Sage Foundation Publications website, with order form and text of Chapter 1.