This is my anthropology essay #2 on sex differences in empathy and aggression.

Biological factors impact sex differences in aggression and empathy, which exist because they had a fitness value for human ancestors in the environment of evolutionary adaptation. Aggression differs in sexes and its pattern of appearance over the human life cycle, in various human cultures, and across species can be varied. Aggression correlates with brain activity and evolved through evolutionary adaptation as a trait that aids survival and procreation. Empathy also appears in certain stages of the life cycle, as well as across all known human cultures, and in many animal species, with differences in sexes. Various types of empathy have their foundation in brain functioning and evolved because they served survival. Understanding the biological and evolutionary foundations of human abilities, emotions, and behaviors related to aggression and empathy, may allow improved regulations in societies and enhance interpersonal and intercultural communication.

Aggression is a hostile behavior that differs between sexes in both direct aggression like fighting, which is more characteristic of males, and in relational aggression like negative networking. Predatory aggression is directed against members of other species, while social aggression is aimed at members of the same species, and defensive aggression arises against other aggressors (Brain Connection 2006). Aggression in society is usually measured by violent crime statistics (Miller: 9/29/2022). There are notable differences in levels of aggression in male and female humans. Men commit the most serious crimes, whereas women tend to kill abusive partners (Miller: 9/29/2022). Men are overwhelmingly involved in wars and intragroup homicide. All over the world, men commit homicide on average 26 times more frequently than women (Furtuna 2014). In a meta-analysis research of 196 studies about sex differences in the level of aggression, a psychologist conducted a mathematical synthesis of the data from 10 countries and established that men are more physically and mentally aggressive than women, especially in their twenties, except for romantic domestic disputes, where women are just as likely to express physical hostility (Arkowitz and Lilienfeld 2010). Aggression is evident in direct and relational hostilities, and the predisposition to violence is linked to masculinity.

Levels of aggression rise and fall during the human life cycle and can differ in various cultures and in other species. Aggression in humans becomes most evident toward the middle of the life span and decreases toward the end. Infants and children tend to have low levels of aggression (Miller: 9/29/2022). At the age of 17 to 29 months, 5% of boys and only 1% of girls engage in frequent kicking and biting, which suggests that biological factors contribute to sex differences in violent behavior (Arkowitz and Lilienfeld 2010). Young boys tend to prefer “rough and tumble” play (Miller: 9/29/2022). In adolescence, between the ages of 12 to 25, aggression increases significantly. Adolescent boys commit about 80% of all violent crimes among youth. In middle and old age the levels of aggression are low again. Cultural practices significantly impact aggressive behavior in the sexes. In foraging cultures, sex differences in direct aggression are significant, even though general aggression levels are lower than in cultures based on farming or pastoralism (Miller: 9/29/2022) In modern traditional cultures like !Kung and Hadza, men specialize in hunting, which is incompatible with motherhood but motivates an aggressive attitude, thus women are primarily gatherers and have less need for aggressive actions (Miller: EEA Lecture). Experiences of modern industrialized cultures without media, literature, and cinema suggest that the behavioral patterns of boys innately differ from that of girls (Furtuna 2014). Across other animal species, males tend to be more aggressive in male-to-male competition, and females aggressively defend babies (Miller: 9/29/2022). Some animals tend to be violent in gaining food or territory (Brain Connection 2006). Across cultures, species, and over the human life cycle, starting in infancy, the pattern of aggression varies and can be impacted by culture.

Aggression is controlled by multiple brain structures with various neurotransmitters involved and varies among sexes. Amygdalae, which are larger in men than women, are activated when individuals feel anger and hostility (Miller: 9/29/2022). In proportion to the more primitive amygdalae, the female orbital frontal cortex that keeps aggression in check is bigger. In men, the motor system is activated in response to provocation, which can lead to aggression  (Marsa 2007). The neurotransmitter oxytocin reduces anxiety and fear, which might enable more aggressive reactions in mothers. The neurotransmitter arginine-vasopressin is released in the amygdala and helps regulate maternal and male aggression. Reactively aggressive youth are usually male, and they have more activity in the amygdala and less in the frontal lobe (Society for Neuroscience 2007). The prefrontal cortex manages impulse control in aggressive behavior and does not become fully myelinated till about age 25. The neurotransmitter serotonin, which aids the functionality of the prefrontal cortex, metabolizes faster in males (Miller: 9/29/2022). People with a history of violent behavior, which tend to be male, show low levels of serotonin, though it is unclear whether the aggressive behavior induces its low levels or vice versa (Brain Connection 2006). In one study, researchers used positron emission tomography, or PET scans, to examine the brains of 41 convicted violent offenders. They found that the participants had reduced activity in the prefrontal cortex and increased activity in subcortical regions compared to the control subjects (Brain Connection 2006). Brain structure and neurotransmitter activity are among the biological factors of aggression, and the functionality differs in the sexes.

The environment of evolutionary adaptation set the selective pressures that shaped aggressive behavior in human ancestors and the sex differences in it. Aggressiveness might have been beneficial for human ancestors because it provided an evolutionary advantage for survival and reproduction. Substantial sexual dimorphism in Hominins suggests high levels of male competition, and therefore aggression. Hunting by men and eating meat in Homo erectus contributed to aggressiveness as well. In traditional societies, hunting remains a male activity (Miller: EEA Lecture). The need for emotional control during group hunting could have helped males partially decouple aggression from killing (Wong 2014). For males, it could have been necessary to be more aggressive to protect the tribe, to compete for females, to have more offspring, and to hunt for animals, while females could benefit from aggression mainly to protect babies (Miller: 9/29/2022). Humans evolved by practicing foraging, and their successful division of labor in food acquisition and child-raring impacted the sex differences in aggression.

Empathy is the ability to understand and share the feelings of others; it differs in women and men. Empathy is related to mirroring, or imitating the movements of others, including reading faces (Miller: 10/11/2022). Emotional empathy is sharing feelings and matching behavioral states. Cognitive empathy, or the theory of mind, is understanding the feelings of others. Compassion adds the motivation to do something about the other’s distress (Denworth 2017). Empathy is usually measured by observation and surveys. The capacity to read facial expressions, essential for some forms of empathy, differs in sexes. Women tend to read faces more quickly and accurately, especially those that express negative emotions and to scan for more details. Men recognize positive emotions better. Women tend to mirror more and are likelier to orient toward each other, while men choose face-to-face settings less (Miller: 10/11/2022). Women are better at processing auditory and visual emotions than men (Science News 2009).  Empathy starts with body synchronization early in life. In one study on a type of empathy known as emotional contagion, a psychologist used small electrodes to register tiny muscle movements in human faces. The screen images were presented to them too briefly to perceive them consciously. People were turning the corners of their mouths down in frowning when they saw angry facial expressions, and up when they saw happy faces. It suggests that humans are naturally empathic, not by choice (deWaal 2009). Emotional empathy, theory of mind, and compassion all have some differences between the sexes.

Sex differences in empathy can be recognized throughout the human lifecycle and are evident in all human cultures and in some animal species. Empathy emerges at age one and develops into adulthood (Denworth 2017). Baby girls give more attention to faces, while baby boys prefer objects. Young girls show more outward expression of empathy than boys, they try harder to ease the pain of a person in need. In middle and older age, women demonstrate more empathy on average (Miller: 10/11/2022). Men are slightly less empathetic and feel pleasure if they see the pain of potential enemies or rivals, while women remain empathic (deWaal 2009). Even with these differences, empathy is universal across human cultures (Miller: 10/11/2022). Predispositions to empathy can be modified through culture due to neuroplasticity, the ability of neural networks to be shaped by behavior. Members of both sexes can be trained throughout life to become either more attentive or less, depending on the requirements of the gender norms or a profession (Miller: 10/11/2022). Individuals of many species help each other in distress (deWaal 2009). Empathy is present in many animal species, more among social than solitary ones, for it aids survival and procreation. Many animals read facial expressions well, along with the body posture and vocalization of others, even across species (Miller: 10/11/2022). Empathy is universal in many aspects for all ages, cultures, and for members of many species, and it can differ in sexes.

Biologically, empathy is assisted with several brain structures and neural communication via neurotransmitters and differs in sexes. Areas of the cingulate cortex, the pain center below the cortex, play a central role in generating empathy. The anterior cingulate cortex is most active when individuals observe pain experienced by others and more active in women. The cingulate gyrus is directly associated with empathy and its social expression and activates faster and longer in females. The analytical prefrontal cortex area tends to light up during empathy tests, which suggests that emotions are analyzed. Additionally, the hippocampus, Broca’s and Wernicke’s areas, managing language, speech production, and learning, are also activated, more in women. In men, activation of memory areas is associated with revenge (Miller: 10/11/2022). Broca’s and Wernicke’s areas are bigger in women (Miller: 10/6/2022), and are especially rich in mirror neurons (Dobbs 2006), which serve as a biological foundation of empathy, and also have higher activity in women (Miller: 10/11/2022). They are scattered throughout the brain and used to mentally imitate and understand actions seen or imagined. One of their sets reacts to actions, and another to its perceived purpose, or intentions, which is foundational for feeling empathy.  In a French study about the neural basis of disgust, scientists used fMRI to find that feeling disgust and seeing a facial expression of revulsion caused the same set of mirror neurons to fire in the insula (Dobbs 2006). If size corresponds to function, the 23% wider corpus callosum might explain women's greater ability to read emotional clues (Gorman and Nash 1992). Tests show that men and women perceive the world in slightly different ways in terms of empathy, and more scientists believe that it reflects functional differences in the brains of men and women.

Empathetic behavior was shaped in sexes over time by the habitat where early humans and their ancestors spent most of their evolutionary history. Empathy probably originated in parental care, arose with motor mimicry and emotional contagion, and developed into compassion with a desire to help (deWaal 2009). In early hominins, mothers cared for children for about five years (Miller: EEA Lecture), their empathy could have provided more chances for survival for their babies, leading to higher reproductive success (Miller: 10/11/2022), and then evolved into empathetic behavior toward family and friends (Denworth 2017). Human’s more recent ancestors, Homo erectus, could benefit from empathy for building highly cooperative communities, food sharing, and caring for children for 10-15 years with the group (Miller: EEA Lecture). Females cared for multiple children at a time with the help of the cooperative group, the alloparents. Cooperative breeding predates the significant enlargement of the brain, so human empathy likely comes from the group care for children in Homo (Hrdy 2009). Women who could bond with each other cared better for their children together. Male bonding during dangerous activities could ensure higher rates of survival. Caring for teens during their most vulnerable period of adolescence could give young people more survival chances. Helping elderly members of the group in their time of need could keep them around longer. Homo sapiens were not consistently pair-bonded, so most care for younger and older people was likely provided by more empathetic females (Miller: 10/11/2022). Children with multiple attachment figures learn to integrate multiple perspectives, which aids empathy, and those best at mind reading would receive better care. In ethnographically recorded hunter-gatherers, where over 40% of kids can die before maturity, mortality rates can be significantly reduced, in some cases cut in half, by the attentive presence of caregivers (Hrdy 2009). The development of empathy in societies with a foraging lifestyle had enhanced fitness for human ancestors, and the evolutionary value of empathy in the context of the environment of evolutionary adaptation lies in enhanced offspring and group survival.

Sex differences in aggression and empathy are caused in part by biological factors and exist because they provided an evolutionary advantage to human ancestors. Under most circumstances, direct aggression is associated more with masculinity, which is evident from violent crime statistics, while feminine aggression manifests more in social and romantic confrontations. Aggression’s pattern of appearance throughout the human life cycle is evident primarily in youth, with sex differences arising from childhood where boys show innate differences in play, and peaking in adolescence, impacted by socialization, with similarities to other species. Aggressive attitudes are associated with multiple brain structures and neurotransmitters, knowledge of which became possible with advanced neuroimaging, and they differ in the sexes. Aggressive behavior evolved primarily for protection and competition to enable higher survival and procreation rates and differed in males and females due to sexual dimorphism and adaptive labor division in genders. Rooted in synchronization and manifested differently in sexes, emotional and cognitive empathy as well as compassion allow understanding of the feelings of others and thereby enhance social cohesion. Innate predisposition to empathy, which is observed in many species and becomes universally apparent in early childhood and maintained into adulthood in humans, can be modified by cultural conditioning and special training. Biological causes of empathy include the functionality of various brain structures and sets of mirror neurons activated by performing, observing, and conceptualizing actions, which differ in sexes as well. The fitness value of empathic behavior under the selective pressures of the environment of evolutionary adaptedness might have been in a significant reduction in mortality rates among group members, especially the young. Understanding human aggressive and empathetic impulses can help improve private and social lives and possibly prevent major adversities like wars, violent crime, and loneliness.