Human behavior

• 1. Introduction

  ›

  Human behavior is the capacity, mental, physical, and social, of people and groups to respond to internal and external stimuli throughout their lives. It is driven by environmental and genetic factors, and shaped by thoughts and feelings that reveal a person's attitudes and values. No single definition captures it, and no one field studies it in full. A psychologist, a sociologist, an anthropologist, a neuroscientist, an economist, and a criminologist can all study the same person and see something different. So how does one species end up needing this many disciplines to explain itself? And what makes human conduct so distinct from that of every other animal? The answers run through how we cooperate, how we punish, how we love, how we lie, and how the brain reorganizes itself across an entire life.

• 2. The Two Forces

  ›

  The nature versus nurture debate sits at the center of the whole subject. It asks whether behavior is shaped predominantly by genetic predispositions or by environmental influences. Genes do not guarantee any particular behavior. Instead, certain inherited traits make a person more likely to act a certain way or to express a certain personality. An individual's environment can also shape conduct, often working together with those genetic factors rather than against them.

  Twin studies are a common way researchers try to separate the two. Twins with identical genomes can be compared to isolate the genetic and environmental contributions to behavior. Through this method, lifestyle, susceptibility to disease, and unhealthy behaviors have all been shown to carry both genetic and environmental indicators. Behavioral genetics examines exactly this, how inherited traits feed into the actions a person takes.

  Neurotransmitters, hormones, and metabolism are all recognized as biological factors in behavior. The human brain has neuroplasticity, meaning its structure changes over time as neural pathways are altered in response to experience. This is what allows learning, and what lets a behavior repeated over time become a habit, performed regularly without a conscious decision to do so. The structure and agency debate frames the same tension at a larger scale, asking whether conduct is led mostly by individual impulses or by external structural forces.

• 3. Norms And Deviance

  ›

  Social norms are the unwritten expectations that members of a society hold for one another. They are ingrained in a particular culture, and people often follow them unconsciously, without deliberation. These norms touch every part of life, including decorum, social responsibility, property rights, contractual agreement, morality, and justice. Many of them help coordinate members of society and prove mutually beneficial, such as the norms around communication and agreements. They are enforced by social pressure, and a person who violates them risks social exclusion.

  Ethical systems guide behavior by determining what counts as moral, and humans are distinct from other animals in using such systems. What is considered ethical depends on the value judgments of the individual and the collective norms about right and wrong. These systems may be derived from divine law, natural law, civil authority, reason, or some combination of principles. Altruism, in which a person weighs the welfare of others equally or above their own, follows from this. Other animals engage in biological altruism, but ethical altruism is unique to humans.

  Deviance is behavior that violates social norms, and because norms vary between people and cultures, the nature and severity of a deviant act is subjective. What a society treats as deviant can also change over time as new norms develop. Deviance is punished through social stigma, censure, or violence, and many deviant actions are recognized as crimes handled by a system of criminal justice. Such punishment may aim to prevent harm, to maintain a worldview and way of life, or to enforce morality and decency. Cultures even attach positive or negative value to physical traits, so that a person lacking a desirable trait can be seen as deviant.

• 4. In-Groups And Conflict

  ›

  When humans make decisions as a group, they engage in politics. People have evolved toward self-interest, but that self-interest includes behaviors that favor cooperation over conflict in collective settings. Individuals form in-group and out-group perceptions, cooperating with the in-group and competing with the out-group. This produces a striking set of behaviors. People unconsciously conform, passively obey authority, take pleasure in an opponent's misfortune, initiate hostility toward out-group members, invent out-groups where none exist, and punish those who fail to meet in-group standards. From this come the political systems that enforce those standards.

  Conflict arises when humans oppose one another. It can come from a disagreement of opinion, from one party obstructing another's goals, or from negative emotions such as anger. A conflict that is purely a disagreement is often resolved through communication or negotiation, but adding emotional or obstructive elements can escalate it. Interpersonal conflict occurs between specific individuals or groups. Social conflict occurs between different social groups or demographics, often when groups are marginalized, lack resources they want, or seek to instigate or resist social change. Significant social conflict can cause civil disorder. International conflict, between nations or governments, may be settled through diplomacy or war.

• 5. Bonds And Belonging

  ›

  Romantic love is a significant interpersonal attraction toward another person, and its nature varies by culture. It is often contingent on gender, occurring together with sexual attraction, sexual orientation, and romantic orientation, and it is tied to many individual emotions. Many cultures place a higher emphasis on romantic love than on other forms of attraction. Marriage is a union between two people, though whether it is bound up with romantic love depends on the culture.

  Individuals closely related by consanguinity form a family, and family structures vary widely, including parents and children as well as stepchildren or extended relatives. Family units with children emphasize parenting, where parents make a high level of parental investment to protect and instruct children over a period longer than that of most other mammals. Relationships in general are developed through communication, which creates intimacy, expresses emotion, and builds identity. An individual's relationships form a social group whose members all communicate and socialize, and those groups are linked by further relationships. People who actively seek out social interaction are extraverts, and those who do not are introverts.

  Human social behavior rests on an advanced theory of mind, the ability to attribute thoughts and actions to one another. Through it, humans have built a society and culture distinct from other animals. Communication relies heavily on language, usually through speech or writing, while nonverbal communication and paralanguage can modify a message's meaning through physical and vocal behavior.

• 6. The Reasoning Mind

  ›

  Humans reason to make inferences from a limited amount of information, and most of that reasoning happens automatically, without conscious effort. It works by generalizing from past experiences and applying those generalizations to new circumstances. Deductive reasoning infers conclusions that are true based on logical premises, while inductive reasoning infers what is likely to be true based on context. Learned knowledge is acquired to make more accurate inferences.

  Emotion is a cognitive experience innate to humans. Basic emotions such as joy, distress, anger, fear, surprise, and disgust are common to all cultures, though norms about expressing them may vary. Other emotions arise from higher cognition, including guilt, shame, embarrassment, pride, envy, and jealousy. These develop over time rather than instantly and are more strongly shaped by cultural factors. Sensory information such as color and music can influence emotion, and people often try to lift one another's moods through consolation, entertainment, and venting. A person can also self-regulate mood through exercise and meditation.

  Creativity uses previous ideas or resources to produce something original, enabling innovation, adaptation to change, and novel problem solving. It includes personal creativity, in which someone presents new ideas authentically, and social creativity, in which a community produces and recognizes ideas collectively. People with specialized knowledge in a field draw on it to develop new ideas, whether new artistic works or scientific theories built through trial and error.

  Religious behavior follows traditions based on the teachings of a belief system, and its nature varies by tradition. Most traditions involve telling myths, practicing rituals, making certain things taboo, adopting symbolism, determining morality, experiencing altered states of consciousness, and believing in supernatural beings. Such behavior is demanding, with high time, energy, and material costs, and it conflicts with rational choice models, though it offers community benefits. According to a Pew Research Center report, 54% of adults around the world said religion is very important in their lives as of 2018.

• 7. The Body's Routines

  ›

  The human sleep cycle takes place over 90 minutes, repeating three to five times during normal sleep. Sleep is driven by homeostatic and circadian factors, with the circadian rhythm calibrated to the day-night cycle and to sleep-wake habits. Homeostasis means that after a period of sleep deprivation, a person sleeps longer to compensate. Humans eat food to obtain nutrition, sometimes for nutritional value and sometimes for pleasure, often preparing it first to make it more enjoyable. Waste is disposed of through urination and defecation, and excrement is frequently treated as taboo, especially in developed and urban communities where sanitation is available and excrement has no value as fertilizer.

  Basic disgust evolved as an adaptation to prevent contact with sources of pathogens, producing a biological aversion to feces, body fluids, rotten food, and animals that commonly spread disease. Hygienic behaviors common to most societies include personal grooming, disposal of human corpses, use of sewerage, and use of cleaning agents. In industrialized nations, better nutrition, sanitation, medical treatment, and birth control significantly improve health, and people exercise beyond what survival requires.

  Humans reproduce sexually, engaging in intercourse for both reproduction and pleasure, and they are unique in intentionally controlling the number of offspring they produce. Mating structures include forms of monogamy, polygyny, and polyandry, heavily shaped by cultural norms. Unlike most mammals, humans ovulate spontaneously rather than seasonally, with a menstrual cycle that typically lasts 25 to 35 days.

  Humans are bipedal and move by walking through the bipedal gait cycle, alternating heel contact and toe off with slight elevation and rotation of the pelvis. Balance while walking is learned during the first seven to nine years of life, and each person develops a unique gait. The endurance running hypothesis proposes that humans can outpace most animals over long distances, aided by self-regulation through perspiration during exertion. The human hand is prehensile, capable of grasping objects and controlling grip strength, which allows the use of complex tools.

• 8. Work, Leisure, And The Screen

  ›

  The simplest societies are tribes of hunter-gatherers who work primarily for sustenance, where work is not a distinct activity but a constant that fills all of life. More advanced societies developed after the Neolithic Revolution, emphasizing agricultural and pastoral work, increasing production, and allowing some individuals to specialize outside food-production. Laborious work in these societies has been carried out by slaves, serfs, peasants, and guild craftsmen. The Industrial Revolution introduced the factory system, under which workers increasingly collaborate, employers act as authority figures during work hours, and forced labor is largely eradicated. Post-industrial societies replace obsolete industries with mass production and service work. The primary motivation for work is material gain, which takes the form of money in modern societies, though it can also build self-esteem, provide activity, earn respect, and express creativity.

  Leisure is activity, or a lack of it, that takes place outside of work, offering relaxation, entertainment, and improved quality of life. It can relieve psychological stress and produce positive emotions, but it can also enable boredom, substance abuse, or high-risk behavior. Serious leisure involves the non-professional pursuit of arts and sciences, the development of hobbies, or career volunteering in an area of expertise. Casual leisure provides short-term gratification through play, relaxation, passive entertainment from mass media, active entertainment in games, and sensory stimulation. Mass consumption began during the Industrial Revolution, and a consumer's purchasing decisions are shaped by a product's nature, cost, convenience, and advertising, along with cultural factors, social class, and reference groups.

  Digital behavior occurs through smartphones, social media platforms, and internet connections, and modern humans spend an average of 6.5 hours per day in online activity, mainly for information retrieval and social interaction. These environments have altered how humans interact and process information, creating social patterns that differ from face-to-face relationships. Like all living things, humans live in ecosystems and interact with other organisms, and they have built man-made ecosystems such as urban areas and agricultural land. Among the animals they keep, dogs and cats have been bred for domestication over many centuries, a reminder that human behavior continually reshapes the environments that shape it back.