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Milestones in the study of affective evolution

Though Darwin launched the theory of evolution and applied it to human emotional life 150 years ago, most of the research on evolved emotions has emerged much more recently, and I’ve had a front row seat observing it. In my twenties at university in the 1970s the flow of data began as a trickle, gathering more strength in the 1980s and 90s and now in the 21st century is a torrent.

Darwin’s book The Expression of the Emotions in Man and Animals in 1872 was the first to present two key ideas: 1) emotional universality: that all humans express key emotions in the same way; and 2) such innate traits arise through our common evolutionary past. These were radical concepts in an era when emotions were thought to be divinely inspired.

But Darwin’s insights on emotional evolution got a tiny fraction of the attention of his ideas on biological evolution. So for about a hundred years after the the publication of his book, his theories were applied to explain universal physical characteristics rather than mental.

But that changed in 1975 with the publication of the bombshell book Sociobiology by E. O. Wilson. The world’s leading expert in the study of ants and their social systems, he argued that evolutionary forces would shape the human mind just as it did the body. For example, guilt could have evolved to dissuade our ancient ancestors from cheating each other, which would have promoted group cooperation rather than conflict, giving any group with that trait a survival advantage over groups without it.

Sociobiology ignited a firestorm of controversy because it contradicted the popular idea that at birth our psyche is a blank slate, leaving culture free to imprint any design. Some people worried that if key elements of human nature were embedded in our genes, a truly democratic society might not be possible. (They were wrong about that. It turns out that our genes love freedom and equality.) Wilson was reviled by many academics, and even physically attacked by an antiracist group. That did not stop him from writing more important books on the subject which earned him two Pulitzer Prizes.

Several other scholars began publishing papers on the evolution of the human mind and by 1992 so many scientists were working in the field that a group of them decided to christen the discipline with a name: evolutionary psychology. That year two dozen scholars contributed to the milestone book The Adapted Mind: Evolutionary Psychology and the Generation of Culture which launched the study of mental evolution. Their papers showed how evolutionary principles could explain the existence of a wide range of universal psychological traits that produced language, child care, sex and social cooperation.

Since then evolutionary psychology has become a research powerhouse with thousands of papers. Steven Pinker’s 2002 wryly titled book The Blank Slate brought the science to the general public.

However the idea of what I call affective evolution, that we moderns acquired an innate set of likes and dislikes (affective biases) stemming from our primal past, got much less attention. In fact science generally has mostly ignored the study of the basic feelings of good and bad, and that trend was visible in evolutionary psychology. Its focus has been largely on behavior rather than affect.

But another new discipline, positive psychology, which formally emerged in the late 1990s a few years after evolutionary psychology, put subjective feelings at the center of its mission. Using surveys and clever experiments all over the world, the researchers began to catalogue a list of experiences that made large majorities of people feel good and bad. Sometimes the positive psychologists would tie these discoveries to our evolutionary past, but often not. As so often occurs in scientific specialties, the two fields operated largely in their own silos with relatively little cross-disciplinary pollination.

In 2000 a leading evolutionary psychologist, Professor David Buss, in his paper “The evolution of happiness” provided the first major overview of the research into the subject in both fields.1 (See References below) Although he touches on the idea of affective evolution, the generality of his paper limited any detailed discussion of it. But his paper is the first to set out the idea that knowledge of our evolved affective biases could guide our behavior to increase our subjective wellbeing. He cited a mix of evolutionary and positive psychology to support his argument.

But the evolutionary happiness idea never went very far. The only full length book on the subject that I know of appeared in 2002 when Professor Bjorn Grinde published Darwinian Happiness: Evolution As a Guide for Living and Understanding Human Behavior. The primal happiness ideas advanced by both Buss and Grinde received little of the spotlight shined on other subjects in evolutionary psychology, such as our moral, sexual or even political behaviors. Similarly, positive psychologists have rather minimally applied the idea of affective evolution to understand happiness, which I argue occasionally leads them astray. One reason I wrote Our Primal Heart, was to provide a more unified theory of happiness.

In the first decade of the 21st century the discoveries of positive psychology began to reach a popular audience. The discipline spawned a new genre of self-help books on happiness. Many became major bestsellers, such as Gretchen Rubin’s The Happiness Project in 2009. There are now hundreds of titles on the subject. But by and large, they ignore evolutionary insights into happiness.

At the same time another genre of self-help books appeared, this one on physical health, and it was based on evolutionary principles. The 2002 book The Paleo Diet by Professor Loren Cordain launched the niche. He argued that our digestive system had been shaped by vast eons living in a hunter-gatherer culture and that we suffer excess weight and health problems because our modern diets vary so dramatically from the primal. The modern paleo health movement now has millions of adherents, and over 100 books, websites and podcasts.

Mark Sisson is the most important voice in this area. A brilliant writer, teacher and entrepreneur, his website and bestselling book The Primal Blueprint has introduced millions of people to the idea that our nomadic roots powerfully affect our modern bodies. Mark is also rare in the paleo world for occasionally examining the impact of a primal perspective on our emotional lives. His book The Primal Connection examines subjects like nature connection, personal relationships and play, but such attention is secondary to his dominant focus, physical health, which is his expertise.

Today most of the writing and practice of the paleo movement continues to be on diet, weight loss, muscle building, endurance and exercise. Paleo enthusiasts have given our emotional life just a tiny fraction of that coverage. So an evolutionary perspective on happiness is largely missing not only from the professional literature but popular books too. Yet it offers much practical guidance for self-helpers in boosting the happiness of our lives. So my book and website aim to provide not only a new unified theory of happiness but also a way to apply it in daily life.

References 1David M Buss, "The Evolution of Happiness" American Psychologist 2000, 55(1):15-23

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