Final Research Paper

 

Explaining Masculinity Through Evolutionary Psychology

 

            When attempting to explain something found in nature it is often useful to approach such a task from a scientific perspective. Scientists devise experiments to prove or disprove hypotheses and draw conclusions about their observations that are founded in fact. When attempting to explain something as intangible and complex as human behavior it is difficult to devise experiments that lead to conclusive results. Sometimes complex problems are easier to solve when they are broken down into smaller pieces or into simpler problems that are more approachable. Using human evolution to explain human behavior is such an example. Evolutionary psychology reaches for the roots of human development when they were in their most basic stages to explain why people behave the way they do. Specifically, explaining human masculinity through science has been a major focus of evolutionary psychology. This paper seeks to explain why masculinity cannot be explained by sociology alone and will present evidence that certain male behavior such as aggression can be explained through evolutionary psychology and sexual selection.

            When considering the source of human behavior people often argue about how much human behavior is encoded genetically and how much is learned through interaction with society and the environment. This “nature versus nurture” debate arises frequently when discussing many aspects of human behavior. In an essay entitled “The Gender Blur: Where Does Biology End and Society Take Over,” Pulitzer Prize-winning professor of journalism Deborah Blum draws the conclusion that both nature and nurture must be taken into account to explain human behavior. Her conclusions are drawn principally from childhood behavior and her discussions with noted scientists. As a parent she observed that her son loved dinosaurs from the early age of two-and-a-half years old. However, she noticed that “he loved dinosaurs, but only the blood-swilling carnivores. Plant-eaters were wimps and losers, and he refused to wear a T-shirt marred by a picture of a stegosaur” (454). She was taught from an early age that “every human being – regardless of gender – was exactly alike under the skin” (453). After raising two boys she questioned the idea that male and female behavior is entirely shaped by interaction with society.

            Blum consulted University of California at Berkeley behavioral endocrinologist Marc Breedlove about how hormones contribute to gender differences. Breedlove’s studies support the idea that there are biological differences between males and females that distinguish each gender’s behavior. This suggests that it’s worthwhile to look at human evolution to understand why these biological differences exist – what is the purpose of masculinity and why do masculine traits such as aggression develop predominantly in males?

            Scientists have suggested that biological characteristics of males predispose them towards certain behavior and statistical evidence exists to support these ideas. Blum examined crime reports in the United States and Europe and noted that men commit ten to fifteen times as many robberies as women (459). She also noted that for those robberies men were twice as likely to use a gun while committing the crime. Daly and Wilson present homicide rates for men and women in their article “Darwinism and the Roots of Machismo.” They found that in the United States, Canada, and England over a time period spanning 15 to 20 years, men committed 10 to 30 times as many homicides as women. Based on these statistics it is clear that men exhibit violent behavior much more frequently than women.

Violent behavior isn’t the only place where men and women differ statistically. Dr. Paul Kenyon of the Human Behavior and Evolution Society presents a research study related to sexual selection differences. The study appears on the University of Plymouth Department of Evolutionary Psychology website but originally appeared in Psychological Review in 1993. The study found that while women favored four to six different sex partners over their lifetime men favored fourteen to eighteen. Kenyon indicates that the research studies he conducted suggest that men and women have different mating goals.

There is sufficient statistical evidence that shows males exhibit more violent behavior than women and have different sexual selection goals. It is also clear that masculinity cannot be explained through society alone and that both nature and nurture play a role in male development. A book entitled Handbook of Evolutionary Psychology: Ideas, Issues, and Applications presents a series of research studies and articles related to evolutionary psychology. Of particular interest to the subject of masculinity is an article by G. F. Miller entitled “How mate choice shaped human nature: A review of sexual selection and human evolution.” On the subject of male aggression Miller presents a research study tying aggression and sexual selection together suggesting that “male primates fight more often and more intensely when estrus females are in their group” (Section 6, Paragraph 2). His research on primates is important because according to Miller “it is hard to reconstruct sexual selection patterns in extinct animals because mate preferences and courtship behaviors don’t fossilize” (Section 6, Paragraph 1). Since fossil evidence does not directly associate what we characterize as masculine behavior with reproductive success, Miller cites several studies in Section 6 of his article that suggest that it is reasonable to extrapolate behavior of human ancestors from the behavior of modern primates.

Miller finds that male aggression in primates often wins the reproductive favor of females because it wards off predators that threaten the females’ offspring. (Section 3.5, Paragraph 3). Based on what scientists have theorized about hominid behavior it is likely that human ancestors faced similar problems. Females required “provisioning and protection” (Section 6, Paragraph 3) and males were more likely to be selected as mating partners if capable of providing such protection. If extrapolated to modern males this could explain why men exhibit aggression much more frequently than women.

This argument is made even stronger considering the fact that males are also involved in the mate selection process and they compete viciously with each other for the opportunity to select the most attractive mate. Daly and Wilson note that in many species males frequently “suffer injury and exhaustion in the process” of mate selection due to competition for females. Blum points out that male chimpanzees “declare war on neighboring troops” during periods of mating (455). She notes that it is advantageous for males to be aggressive because in doing so they “muscle their way into dominance, winning more sexual encounters,” giving them a stronger genetic future (455). This is an important difference between males and females – because females are only capable of a single pregnancy in a year there is no genetic advantage to aggressively fighting for multiple mates.

Miller suggests another explanation for why hominid females may have selected mates based on behavioral characteristics. He argues that because “there is no sharp division between the body and brain” it is not unreasonable to suggest that if evolution occurs at a physical level it should also occur at a mental level. (Section 7) He notes that even the simplest bodily adaptations have “physiological, neurological, and psychological features” suggesting that as females selected mates based on bodily characteristics they were simultaneously selecting male behavioral traits. Although mate selection itself is a mental process, criteria used for selecting mates is often physical, which causes the neurological features associated with these physical features to be selected at the same time. Daly and Wilson define sexual selection in their article “Darwinism and the Roots of Machismo” as “the component of Darwinian natural selection that consists of non-random differences in mating success.” They note that “over evolutionary time, sexual selection engenders distinct attributes in females and males whenever the mating tactics that leave the most descendants are different for the two sexes.” Evolutionary psychology finds that masculine traits such as aggression have developed because they were evolutionarily advantageous. Because males are capable of producing multiple offspring by mating serially with different females it is advantageous for them to evolve the masculine traits that best suit them for doing this. Aggression is one of the male traits that result in greater reproductive success in males.

Although there is plenty of evidence to support the idea that aggression in males was useful to our ancestors and in modern primates, what evidence is there that human and primate sexuality has not diverged over thousands of years? In a book entitled “Demonic Males: Apes and the Origins of Human Violence”, Dale Peterson and Richard Wrangham introduce evidence that suggests that human sexuality has not diverged as dramatically from primates as we may think. Peterson and Wrangham point out that St. Augustine suggested that humans are the only animals who challenge “the inseparable connection … between the two meanings of the conjugal act: the unitive meaning and the procreative meaning” (413). There is evidence to the contrary. In particular, research finds that bonobos appear to have sex for pleasure, and use it to “deepen relationships” and “comfort each other” (413). Based on such research of primate sexuality, there is no convincing evidence that suggests human sexuality has diverged from primate and hominid sexuality dramatically over time.

Sexual dimorphism is another strong indicator that ancestral mate choice patterns have carried through to modern humans. Based on research by Daly and Wilson that is presented in their article, physical differences between males and females such as height and mass indicate that there is a moderate level of sexual competition between males for females. As Daly and Wilson explain it “the difference in male and female body size – less extreme than in the other great apes but greater than in exemplary monogamists – suggests that we evolved under conditions of slight effective polygyny.” Daly and Wilson’s research found that the degree of polygyny practiced in a particular species usually results is greater sexual dimorphism due to the fact that there is more competition between males. The fact that humans are also sexually dimorphous suggests that males carry physical and behavioral traits that equip them for competition for females.

It is impossible to attribute masculine behavior to biology or society alone. To attribute male behavior entirely to social influences would require ignoring the biological differences between men and women that lead to behavioral differences. Sufficient scientific evidence exists that indicates certain masculine behaviors such as aggression have evolved out of necessity for successful sexual selection and these behaviors remain part of modern men. Observing the behavior of primates allows us to extrapolate what the behavior of our human ancestors was like. From these observations we find that certain aspects of masculinity exist largely in part to meet the ancestral needs of sexual selection but remain prominent features of modern male behavior.

Works Cited

Blum, Deborah. “The Gender Blur: Where Does Biology End and Society Take Over?” Signs of Life In the USA: Readings on Popular Culture for Writers. Ed. Sonia Maasik. Boston, MA: Bedford/St. Martin’s, 2000.

 

Crawford, Charles and Dennis L. Krebs. Handbook of Evolutionary Psychology: Ideas, Issues, and Applications. Mahwah, NJ: Lawrence Erlbaum Associates, 1998.

 

Daly, Martin and Margo Wilson. “Darwinism and the Roots of Machismo.” Scientific American (2002).

 

Kenyon, Paul. “Overview of Evolutionary Psychology and Mating Strategies.” Human Behavior and Evolution Society. 2000. University of Plymouth. 4 Apr. 2000 <http://salmon.psy.plym.ac.uk/year3/PSY339EvolutionaryPsychology/EvolutionaryPsychology.htm>.

 

Peterson, Dale, and Richard Wrangham. Demonic Males: Apes and the Origins of Human Violence. Mariner Books, 1997.