Chapter 21: Biology and Personality

Part 3: Sociobiology and Evolutionary Influences on Behavior

Sociobiology is a relatively new field of study that applies evolutionary biology to social behavior (Barash, 1977; Wilson, 1975).  Although much of the research underlying sociobiology has been conducted with non-human animals, the value of this research and its applications to understanding human behavior and personality should not be underestimated.  Samuel Gosling and his colleagues have demonstrated that a wide variety of other animal species have personality traits similar to those of humans (Gosling, 2001; Gosling & John, 1999; Gosling, Kwan, & John, 2003; Gosling & Vazire, 2002; Jones & Gosling, 2005; Mehta & Gosling, 2006).  When the ethologists Nikolaas Tinbergen, Konrad Lorenz, and Karl von Frisch shared the Nobel Prize in 1973, it was the first Nobel Prize awarded for the study of behavior.  Sociobiology, a field similar to ethology, has offered valuable new perspectives on human behavior, perspectives on behaviors that do not always seem logical at first.  As an aside, sociobiology also allows us to address an exciting variety of human behaviors, including the apparent evolutionary and neurobiological bases for laughter (see Panksepp, 2005).

The fundamental concept underlying sociobiology is that of inclusive fitness.  Inclusive fitness refers to the advantages of behaviors that increase the likelihood of an individual’s genetic survival through the survival of genetically related kin (Barash, 1977; Wilson, 1975).  Therefore, in looking at the evolution of human social behavior, we must not only consider the ways in which behaviors contribute to individual survival (which is a traditional Darwinian perspective on survival of the fittest), but rather on how behaviors contribute to the survival of our children, family, and perhaps even our community.

This is a color photograph of five people aligned in a row demonstrating the changes in human development through evolution. The person on the far left is walking on all fours; the next person in line is walking hunched over with his arms dangling in front; the next person in line is walking upright but with a curved back; the next person in line is walking upright while holding a stick across her shoulder; and the person on the far right is walking upright while looking down at the cell phone he is holding in his right hand.
Image Source: jplenio. Retrieved from Pixabay at Licensed under CCO.

Sociobiologists have looked at several major topics regarding the evolution of human behavior, but we will only take a brief look at three behaviors: mate selection, parenting, and religion.  The differences between male/female have become commonly accepted in the popular media, and evidence suggests that men and women are inclined to essentialize their differences (Prentice & Miller, 2006).  In contrast, Janet Shibley Hyde has provided compelling evidence that men and women are actually much more alike than they are different (Hyde, 1996, 2005; also see Spelke, 2005; Stewart & McDermott, 2004).  So which is it? When it comes to mate selection, sociobiology suggests that men and women should be different, because the roles they will need to play in eventual child rearing require them to be different.  It is a biological fact that men need to contribute very little to the birth of a child, whereas women become pregnant for nine months and, from an evolutionary perspective, must then breast-feed the child for one or two years.  Thus, a man can improve his inclusive fitness by seeking multiple relationships with women in their prime child-bearing years and exhibiting physical characteristics indicative of good reproductive health. Unfortunately, other men are looking for the same women, so competition can become fierce.  Women, on the other hand, should be inclined to seek men who have already won those competitions, demonstrating that they can provide and protect resources for their offspring, usually by commanding a territory or a privileged place in society (Barash, 1977; Wilson, 1975, 1978). So it is not uncommon for women to be inclined to marry older men, particularly men who are above them on the socioeconomic scale (Barash, 1977).  Women would also be inclined to select men who make some commitment in terms of child rearing (Barash, 1979). So, men who were inclined to make only the minimum commitment necessary to the sexual act did not improve their inclusive fitness, since they were not selected by discriminating females.

When parenting is discussed in introductory psychology courses, the most common topic is parenting styles and their influence on personality development.  In sociobiology, however, the most relevant issues are the survival of the offspring and how taxing it is on the parents to help their offspring survive. We are just beginning to understand some aspects of the biological basis for attachment from the offspring’s perspective (Hofer, 2006), but understanding the attachment of the parent to the offspring remains elusive.  Obviously, raising a child requires a considerable amount of effort on the parent’s part, but typically more on the part of the mother. Thus, close social bonding is important, and this may form the basis of love as an added emotional component to sex, as well as the growing love that parents feel for their children (Barash, 1977; Wilson, 1978). Older women are particularly more sensitive to the needs of first-born children, since the child may well represent the only opportunity for the mother to reproduce.  Nature is full of well-known examples of female animals vigorously defending their young, even if their own life is endangered (Barash, 1977, 1979). Of peculiar interest is the behavior of grandparents, since a parent is really only successful in reproducing if they eventually become grandparents. Barash (1977) discusses two interesting situations. When a child is born, it is most likely that the mother’s parents come to help. But if a young couple chooses to live with parents, it is most likely the father’s parents.  These may simply seem to be cultural artifacts, but they have a basis in biological fitness. Only a mother can be sure that she has made a genetic contribution to a child (at least in the past, when our behaviors were evolving). So, when a woman has a baby, only her parents are sure that they have become grandparents. The man’s parents serve their own interests best if they can watch over the woman, to make sure that she does not stray from her relationship with their son (Barash, 1977). All of this may sound cold and calculating, but it is logical nonetheless, and if we believe in an unconscious mind, then people don’t need to be aware of exactly what they are doing.

Religion has been a profound influence throughout the history of the human species.  It has been suggested that children naturally seek a divine explanation for the existence of a world they cannot comprehend (Kelemen, 2004).  But what evolutionary advantage might religion serve? This question is difficult to answer, in part because religion appears to be unique to the human species.  Many of the principles of sociobiology were determined by working with lower animals, especially the social insects. Without other species to use for comparison, it is not easy to understand our own species.  According to Wilson, the best avenue for understanding the advantage conferred by religion to inclusive fitness is the ability to conform to the expectations of society. Humans seem to seek indoctrination. As we became more intelligent, more capable of making individual choices, perhaps we evolved the behavioral predispositions necessary to continue remaining within our tribe.  As a result, the rules and rituals that developed to codify this behavior enhance the survival of our group, and it is this group-selection that sociobiologists recognize as the evolutionary advantage resulting from religion (Boyd & Richerson, 1985; Wilson, 1975, 1978). This is not unlike the role ascribed to religion by Sigmund Freud, except that sociobiologists propose an underlying genetic basis, whereas Freud proposed an underlying psychodynamic basis.

One of the most common negative reactions to sociobiology is resistance to the idea that we are still animals being driven by our genes and evolution.  The simple logic provided by sociobiologists, and the clear parallels between human behavior and the behavior of other animals, is not enough to sway the minds of some people.  Culture definitely plays a significant role in our lives, gene-culture co-evolution may underlie human cooperation and altruism (Henrich, et al., 2006), and separating genetics from culture on a topic such as mate selection is difficult (Buss, 2003; Miller, Putcha-Bhagavatula, & Pedersen, 2002).  But is culture something different than evolution? Richard Dawkins, in his profound book The Selfish Gene (1976), has proposed that the human mind has evolved to a point where it can create self-replicating units of culture, which he called memes.  Memes can be transmitted from person to person, and they can evolve faster than genes.  Thus, human culture has been able to outpace genetic evolution, creating many of the challenges we face today when we try to separate culture from genetics in order to understand complex human behaviors.  As examples, let us consider two potential memes: belief in God, and belief in life after death. As mentioned above, children appear to be inclined to believe in a supernatural creator of the world that they, as children, simply cannot understand.  And religion is a cultural universal. Not every religion, however, believes in life after death, and even fewer believe in heaven or hell. So religion appears to be a very successful meme, whereas belief in life after death is somewhat less successful, but successful enough to still be prevalent.  One of the most fascinating aspects of memes is that they may actually increase the likelihood that you can have a very long lasting effect on the world. As Dawkins points out, Queen Elizabeth II of England is a direct descendant of William the Conqueror, but the odds are very low that she has even a single gene descended from him.  So, immortality cannot really be achieved through reproduction:

But if you contribute to the world’s culture, if you have a good idea, compose a tune, invent a sparking plug, write a poem, it may live on, intact, long after your genes have dissolved in the common pool.  Socrates may or may not have a gene or two alive in the world today…but who cares? The meme-complexes of Socrates, Leonardo, Copernicus, and Marconi are still going strong. (pg. 214; Dawkins, 1976)

According to Richard Dawkins, the true path to immortality is found through cultural contributions to society, by virtue of cultural units he called memes.  What memes do you think are important in your life and in your community? Has that changed during your life and, if so, why?

Evolutionary Psychology

The field of evolutionary psychology is a direct application of sociobiology to psychology, and appears to have begun with the publication of The Adapted Mind (Barkow et al., 1992).  In this landmark book, a collection of authors were brought together with the purpose of addressing three major premises:  (1) that there is a universal human nature, but that it is based on evolved psychological mechanisms as opposed to culture, (2) that these psychological mechanisms were adaptations constructed by natural selection, and (3) that these adaptations fit the way of life of our ancient ancestors, and may not fit our modern circumstances.  Similar to the sociobiologists, evolutionary psychologists examine how evolution shaped human behavior and cognition in ways that helped individuals to pass on their genes to future generations, covering topics such as cooperation, mate preference, parental care, the development of language and perceptual abilities, the individual need to belong, helping and altruism, and the universality of emotions (Barkow et al., 1992; Buss, 1999; Larsen & Buss, 2005).

One of the best known psychologists studying evolutionary phenomena is David Buss, and he has paid particular attention to how we choose and attempt to keep our mates.  In The Evolution of Desire, Buss (2003) describes how biological differences between males and females leads to different mating strategies, and that this should lead to inevitable conflict.  Thus, according to Buss, conflict in a marriage is the norm, not the result of choosing the wrong person. As a result of this conflict, and for a variety of reasons underlying it, the possibility always exists that a man or woman in a marriage (or other committed relationship) will engage in other sexual relationships outside of the marriage.  In order to defend against this potential loss of a committed mate, it was an advantage for people to evolve the emotion of jealousy. In The Dangerous Passion, Buss (2000b) argues that jealousy is just as important as love and sex.  Passion is necessary for us to have motivation (consider Jung’s description of the shadow archetype).  But with jealousy, “Jealousy can keep a couple committed or drive a man to savagely beat his wife. An attraction to a neighbor’s spouse can generate intoxicating sexual euphoria while destroying two marriages” (pg. 2; Buss, 2000b).

This is a color image of three people's faces within the shape of a heart. There is a male located on the left, and he is looking forward to a woman to his right. In the top center of the heart is a second woman with a solemn look on her face. There are flames covering part of the heart.
Image Source: Geralt. Retrieved from Pixabay at Licensed under CCO.

Indeed, the competition that accompanied the desire to obtain and hold onto a mate in our distant past was so intense that we also evolved the psychological mechanisms necessary to kill people.  Although this psychological mechanism may be maladaptive in our society today, its effectiveness in the prehistoric past remains hidden just below the surface of our minds. As a result, it can come out suddenly, explaining why the majority of murderers seem to be normal individuals until the day they kill someone (often someone they know and care about; Buss, 2005).

We have a tendency to think of things such as marital conflict, marital infidelity, jealousy, and murder as abnormal situations.  Evolutionary psychologists suggest instead that such behaviors are the result of natural adaptations. However, as noted above, these adaptations were appropriate for our ancient ancestors, and may not fit within our society today (murder is illegal).  Yet, these behaviors and emotions are common, suggesting that we can’t simply dismiss them. Since evolution typically takes a very long time, it is hard to say whether different adaptations will occur in the future of our species, given the cultural changes that have occurred throughout history.  Perhaps the best we can hope for now is a continued development of our understanding of personality, through a variety of theoretical perspectives.

Connections Across Cultures:  The Somatic Psychology of Wilhelm Reich

Wilhelm Reich (1897-1957) was a respected student and colleague of Sigmund Freud, a political activist, and eventually a convicted criminal in the United States whose books and journals were burned by the American government.  But he left behind a legacy of focusing on the body and mind as deeply interrelated. In Germany in the 1930s, Reich devoted extraordinary effort to programs addressing sex education, sex hygiene, access to birth control, etc. He gave up his psychoanalytic practice because he felt that sex education programs had the potential to be more helpful to more people by preventing sexual and psychological difficulties.  Despite the so-called sexual revolution of the 1960s, many of these issues still plague society today. Reich’s description of the phases involved in the experience of an orgasm (first studied in the 1920s and 1930s) anticipated the famous research of Masters and Johnson (1966), and incorporated a psychoanalytic view of mindsets occurring during sexual activity (Reich, 1973). His work on somatic psychology relates to physical approaches to psychotherapy that continue today.  These contributions and controversies earned Reich a place in the marvelous history of the study of mental illness entitled Masters of the Mind (Millon, 2004).

Raised on a farm, Reich was interested in animal husbandry and conducted extensive studies of animal sexual behavior.  As a young child, he witnessed one of the family’s maids having intercourse with her boyfriend. When he asked the maid if he could “play” the lover, she obliged.  When he was 12 years old, he caught his mother having an affair with one of his tutors. In a classic example of the Oedipus complex, he considered using the information to blackmail his mother into allowing him to have sexual intercourse with her.  Instead, he turned again to one of the family maids. He then told his father, whom Reich had witnessed beating his mother in the past, and shortly thereafter his mother committed suicide. For the rest of his life, Reich was tormented by the thought that he may have been responsible for his mother’s death.  His father died when Reich was 17 years old, and Reich took over the family farm until it was destroyed in World War I.

While attending medical school at the University of Vienna, Reich joined the Vienna Psychoanalytic Society where he began studying with Sigmund Freud.  Reich and Freud were deeply impressed with one another. Reich eventually held several important positions in Freud’s training clinic, including Director of the Seminar for Psychoanalytic Therapy, and his work on character analysis was widely respected.  Indeed, Reich was so involved with the society, Freud, and the clinic that many people thought of him as “Freud’s pet” (Higgins, 1973; Sharaf, 1983).

However, Reich fell out of favor with the psychoanalytic society.  In 1930, he moved to Germany, joined the communist party, and became active in a variety of sex education and sex hygiene programs.  But the communists opposed progressive sex education because they hoped to gain the favor of the Catholic Church, in opposition to the growing threat of the Nazis.  Reich stepped right into this dangerous controversy, often relating one particular story of how moved he was when a young pregnant girl sought his help; help she had not received from the Hitler Youth (Sharaf, 1983).  In 1933, he published The Mass Psychology of Fascism, a book subsequently banned by the Nazis (Reich, 1933/1970).  Eventually, Reich was excluded from both the Communist Party and the psychoanalytic society.

Reich left Germany for Denmark, and then moved to Norway, where his life and work began to take a strange turn.  He became convinced that he had discovered a primordial cosmic energy, orgone energy, which provided the underlying energy for all life.  He believed that orgone energy streams created hurricanes and galaxies.  He built orgone energy accumulators, and began studying how it might be used for such diverse goals as treating cancer and controlling the weather.  He was compelled to leave Norway, and in 1939, moved to the United States. Eventually, however, the U.S. Food and Drug Administration (FDA) sought an injunction in federal court to put an end to Reich’s work on orgone energy.  Reich refused to appear in court, and the injunction was issued in default (see Greenfield, 1974). Reich was accused and found guilty of criminal contempt, and sentenced to two years in federal prison. The FDA destroyed much of Reich’s equipment, and burned tons of his papers and books.  In 1957, Reich suffered a heart attack and died in the Federal Penitentiary at Lewisburg, Pennsylvania.

Somatic Psychology

Reich’s psychoanalytic work emphasized three important topics: the intimate relationship between body and mind, the character of the individual, and the value of precise diagnosis.  By the 1920s, Freud and his colleagues had stopped paying much attention to the concept of libido. In contrast, Reich became more and more interested in this sexual energy, which he associated directly with sexual activity.  While working with his patients, Reich was impressed by their descriptions of feeling an “emptiness” in their genitals. This was an especially interesting point regarding women, since Reich himself considered the sexual inhibition experienced by many women as something appropriate to their development.  However, as Reich pursued these ideas, he began to question the completeness and accuracy of Freud’s theories. Reich developed what became known as the orgasm theory, and he proposed the concept of orgastic potency.  According to Reich (1973), “Orgastic potency is the capacity to surrender to the streaming of biological energy, free of any inhibitions; the capacity to discharge completely the dammed-up sexual excitation through involuntary, pleasurable convulsions of the body…”  (pg. 29)

Reich considered the ability to enjoy sexual release as a critical aspect of normal and healthy personal development.  This perspective demands a direct link between the body and the mind, since only through physical satisfaction can psychological and emotional satisfaction be achieved.  When discussing neurotic symptoms, he described orgastic impotence as the “somatic core of the neurosis…” (Reich, 1933/1972). To further emphasize the point, Reich did not merely consider the ability to have meaningful sexual relations as important, he believed that they needed regular satisfaction.

Reich’s most widely respected work within the psychoanalytic community centered on character analysis, in which he emphasized character armoring and character resistance.  Both of these constructs can be viewed as defense mechanisms, but they are deep and secondary fragmentations of the ego.  Thus, they define the very character of the patient, and must be removed before traditional psychoanalysis can be effective.  In keeping with the term somatic psychology, Reich addressed the physical manifestation of character armoring as muscular armor.  Individuals who are actively character armoring demonstrate what Reich described as a chronic, frozen, muscular-like bearing.  He believed that the visible muscular rigidity was the natural consequence of inhibiting aggression, and that it could be understood on the basis of only one principle:  “the armoring of the periphery of the biopsychic system” (Reich, 1933/1972). In other words, the body physically responds to what the mind is doing; if the mind is defending itself, the body prepares to defend itself.  This muscular tension is by no means easy to remove. If the analyst tries to get the patient to relax, the muscular tension is replaced by restlessness. Based on his theories, Reich described two basic types of character: the genital character and the neurotic character.  The genital character refers to individuals who are relatively healthy in terms of their psychological development, and their capacity to enjoy life is uninhibited.  The neurotic character is governed by rigid armor of both body and mind.

Many psychologists and a variety of practitioners in other areas have made the connection between body and mind an important part of their studies and their lifestyle.  For example, we often “talk” with our hands (Goldin-Meadow, 2006), forced stereotypic movement leads to stereotypic thoughts about others (Mussweiler, 2006), young infants integrate their body movement and their attention (Robertson, Bacher, & Huntington, 2001), physical movement is more important than visual information for effective navigation (Ruddle & Lessels, 2006), and members of different cultures actually perceive the physical environment in different ways (Miyamoto, Nisbett, & Masuda, 2006).  Yoga has become very popular in the United States, particularly the physical aspect of Hatha Yoga, and Yoga practitioners talk about understanding and respecting the body (e.g., Scaravelli, 1991; Stewart, 1994). This is particularly true as we age, since “we all die sooner or later, but what we must do is not allow the body to degenerate while living” (Scaravelli, 1991).

Reich referred to a “genetic differentiation of character types” and the “genetic-dynamic theory of the character” long before other psychologists were talking about the heritability of personality or gene-environment interactions.  Reich went on to say that the social and economic/political factors that play such an important cultural role in personality development would not be as influential as they are if not for the likelihood that they “must first have impinged upon and changed human needs before these transformed drives and needs could begin to have an effect as historical factors” (Reich, 1932/1972).  This sounds very much like sociobiology: the selection of behaviors, behaviors that are determined genetically, as adaptable to the relevant human condition. If indeed this idea does reflect the same basic premise as sociobiology, then Reich was thinking about a new field of research into human behavior that was still over 40 years in the future. In his discussion of muscular armor, Reich referred to three primary emotions that influence human behavior:  sexuality, anxiety, and anger or hate (Reich, 1932/1972). Gotama Buddha (who most people think of as the Buddha) described three root causes of human suffering:  desire, delusion, and hatred. What is sexuality but the greatest desire in human life?  According to sociobiologists, particularly Dawkins (1976), life is about ensuring the propagation of individual genes, and in our case that means sexual reproduction.  In addition, both Reich and the Buddha acknowledged hatred as key, and Buddhists typically see hatred as the antithesis of desire. Thus, Wilhelm Reich, once regarded as Freud’s “pet,” had incorporated both ancient Eastern philosophies and the as-yet unknown field of sociobiology into a cohesive theory of human character, while still in his mid-thirties.  One can only imagine what he might have accomplished had he not pursued the odd theory of orgone energy, which led to his being ostracized and, ultimately, to the federal prison where he died.

Supplemental Materials

Biological Theory

This video [5:32] addresses the role evolution and biology play in our personality development.



The Misunderstood Genius of Wilhelm Reich with Jeffrey Mishlove

This video [11:31] discusses the life and work of psychiatrist, Wilhelm Reich, who is widely regarded as having introduced the importance of the human body into the field of psychotherapy.



The Biological Basis of Personality

This video [16:53] features “Dr. T” explaining her biological basis of personality in a simple and entertaining way.



Is Your Personality Pre-Determined?

This video [8:02] describes personality psychology, evolutionary psychology, heritability and the biological perspective of personality.



Text:  Kelland, M. (2017). Personality Theory. OER Commons. Retrieved October 28, 2019, from  Licensed under CC-BY-4.0.

Shreena Desai. (n.d.)  Behavioral theory. [Video File].  Khan Academy.  Retrieved from

New Thinking Allowed with Jeffrey Mishlove.  (2018, March 21). InPresence 0020: The misunderstood genius of Wilhelm Reich with Jeffrey Mishlove.  [Video File]. Retrieved from Standard YouTube License.

TEDx Talks.  (2012, October 24).  The biological basis of personality: “Dr. T” Tina Thomas at TEDxCitadelPark.  [Video File]. Retrieved from Standard YouTube License.

Practical Psychology.  (2019, April 23). Is your personality pre-determined? Biological theory of personality.  [Video File]. Retrieved from Standard YouTube License.


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PSY321 Course Text: Theories of Personality Copyright © by The American Women's College Psychology Department and Michelle McGrath is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.