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What are the four causes of behavior?

Behavior is complex and often influenced by multiple factors. Psychologists have identified four main causes that shape behavior: biology, thoughts/beliefs, environment, and unconscious factors. Understanding these four causes can provide insight into why people act the way they do.


Biology refers to our genetic makeup and physiology. Our DNA, hormones, brain chemistry, and neural wiring all impact our personality, emotions, intelligence, and behaviors. For example:

  • Genetics influence traits like extraversion, aggression, and risk-taking.
  • Hormones like testosterone, estrogen, and cortisol affect behavior.
  • Neurotransmitters like serotonin and dopamine shape personality and mood disorders.
  • Brain anatomy differences are linked to mental illnesses like schizophrenia and addiction.

Biological factors can increase vulnerability for certain behaviors, but don’t determine them. Environment and thoughts still play a role in how genetics are expressed.

Examples of biological causes

Here are some examples of how biology influences behavior:

  • Aggressive behavior is linked to high testosterone.
  • Risk-taking behavior is associated with lower serotonin.
  • ADHD symptoms are caused by atypical dopamine activity.
  • Postpartum depression is triggered by hormonal changes after giving birth.

Thoughts and Beliefs

Cognition refers to the mental processes involved in thinking, knowing, remembering, judging, and problem-solving. Our thoughts, beliefs, and expectations shape how we perceive situations and behave.

For example, someone’s belief that the world is dangerous may lead to increased anxiety and avoidance behaviors. Or, positive expectations about the future can lead to goal-oriented actions to make those beliefs come true.

Cognitive Causes of Behavior

  • Attitudes: Evaluative beliefs that predispose actions.
  • Attributions: Perceived causes for events that inform future behavior.
  • Cognitive biases: Systematic errors in thinking that influence decisions.
  • Mental filters: Focusing on certain details while ignoring others.

Therapies like CBT aim to change maladaptive thought patterns that contribute to problematic behaviors. Challenging irrational beliefs and shifting cognitive biases can lead to better behavioral outcomes.


The environment we’re exposed to affects our experiences and behavior. Key environmental factors include:

  • Physical spaces and settings
  • Other people and social dynamics
  • Reinforcements like rewards and punishments
  • Observed behaviors and modeling
  • Sociocultural influences and norms

For example, violent video games and aggressive peers can model antisocial behavior. Or, a classroom environment with frequent rewards encourages student participation. Even small environmental tweaks like improved lighting or noise reduction can shift behavior.

Behavioral Theories About Environment

Here are some of the main behavioral theories about how environment impacts actions:

Theory Description
Behaviorism Behavior is learned through conditioning, reinforcements, punishments, and modeling.
Social Learning Theory People learn by observing others and modeling behaviors.
Situationism Specific situations and contexts drive behavior more than character.

Adjusting environmental conditions can shape behavior, like rearranging a classroom to reduce distractions. People also actively select environments congruent with genetic predispositions.

Unconscious Factors

The unconscious mind influences actions in ways we don’t realize. Parts of the mind like instincts, pent-up emotions, and latent memories can manifest through behaviors.

Sigmund Freud emphasized the role of the unconscious in shaping personality and actions. His psychoanalytic theory proposed that unconscious drives and conflicts strongly impact behavior. Key unconscious components he identified include:

  • The id – Primal impulses and desires
  • The superego – Internalized moral standards
  • The ego – Mediator between the id and superego

When unconscious urges and restraints are out of balance, it can cause psychological distress and problematic behaviors. Repressed emotions may also emerge indirectly through actions.

Projective Tests

Psychologists use projective tests like the Rorschach inkblot test to uncover unconscious aspects of personality. Although controversial, projectives can reveal themes individuals may not openly share:

  • Unconscious inner conflicts
  • Thought patterns
  • Emotional states
  • Self-perceptions
  • Drives and motivations

Projective tests help gauge how unconscious factors shape personality and behavior when direct queries don’t provide full insight.


Biology, cognitions, environment, and the unconscious all contribute to human behavior in different proportions based on the individual and situation. While behaviors can seem puzzling from the outside, they tend to be driven by internal logical causes from the actor’s point of view.

Psychologists continue researching how these four factors interact. However, having a framework of the four causes can aid in understanding ourselves and others. Assessing multiple angles of why we do what we do leads to self-discovery and fosters compassion.