Behave

Why do we act the way we do? Understanding human actions requires looking at the interplay between biology, environment, and culture.

1. Behavior is shaped by biology, culture, and history

Our actions are the result of complex interactions between our biological makeup and the environments we inhabit. The brain's evolution influences how we react to immediate situations, like a survival threat, by triggering ancient brain regions that process instinctual responses like fear. For instance, someone in a dangerous area may react aggressively because their brain is conditioned to sense heightened danger.

Simultaneously, the experiences we grow up with, such as living in a violent or peaceful society, affect how we respond to situations. Societies shape behaviors across decades, ingraining patterns based on cultural norms. Additionally, longer historical and environmental forces, like ancestral geographies, have molded civilizations and their collective mentalities over thousands of years.

To fully comprehend human behavior, an interdisciplinary approach is necessary, pulling from neuroscience, culture, and history to explore how biology and societal influences interact.

Examples

• Inherent fear responses triggered by the amygdala can prompt sudden defensive actions.
• Children raised around violence often mimic aggressive patterns as adults.
• Different geographical conditions historically shaped both civilizations and societal morality.

2. The amygdala and frontal cortex control aggression

The decision to act aggressively involves a split-second interaction between the amygdala and the frontal cortex. The amygdala, responsible for processing fear and anger, can fuel aggressive impulses. For instance, brain scans have shown that viewing fear-inducing images activates this region.

The frontal cortex, on the other hand, regulates these impulses, evaluating whether acting out aggressively is appropriate or not. Stories like that of Phineas Gage illustrate this well; damage to his frontal cortex left him unable to control his emotions or regulate his aggression.

Research into criminal behavior reinforces this link. Many violent offenders show diminished frontal cortex activity, hindering their ability to manage impulsive actions. This division between two areas of the brain underscores the biological foundation of aggression and self-control.

Examples

• Charles Whitman’s murderous impulses were traced back to a tumor pressing on his amygdala.
• Phineas Gage’s changed personality after a frontal cortex injury illustrated its role in behavioral regulation.
• Studies have found reduced frontal cortex activity in violent criminals.

3. Sensory cues steer behavior in subtle ways

Visual, auditory, and social cues in our surroundings influence immediate reactions, often without our conscious awareness. The brain is finely tuned to respond to sensory input, such as skin color or environmental sounds, which can skew perceptions.

For instance, studies revealed that when white participants were shown images of faces from different ethnic groups for a fraction of a second, their amygdala lit up in response to unfamiliar racial features. This reaction can inadvertently feed into biases. On a social level, men display risky or generous behaviors around women, driven by underlying mating instincts.

Auditory stimuli work similarly. A black individual might whistle classical music at night to minimize appearing threatening, as cultural associations with certain music trigger the amygdala differently. These subtle cues highlight how easily the brain reacts to its surroundings.

Examples

• Briefly showing an unfamiliar ethnic face activated amygdala responses in white participants.
• Defense attorneys have used tactics like outfitting black clients with non-threatening glasses to influence juries.
• Men exhibit showier purchasing behavior around women, instinctively signaling status.

4. Hormones influence actions but depend on context

Hormones like testosterone and oxytocin impact behavior but in nuanced ways. For example, elevated testosterone doesn’t directly cause aggression. Rather, aggressive situations boost testosterone production, creating a feedback loop. Prison studies back this up--aggressive inmates had high testosterone levels triggered by their environment.

Oxytocin, the “bonding hormone,” encourages trust and social connections. However, it doesn’t function universally. In economic games, elevated oxytocin led people to trust others more when physically present but had no effect in anonymous situations.

Hormones work through interconnected biological systems, driving behavior within specific contexts rather than in isolation, proving how biological responses are influenced by circumstances.

Examples

• Aggressive inmates showed high testosterone, driven by their behavior.
• Elevated oxytocin helped players trust others in person during experiments.
• Castration reduces testosterone and subsequent aggression, but only in certain settings.

5. Early experiences deeply affect personality

Childhood and adolescence profoundly shape brain and behavioral development. Although the brain largely forms by age two, key regions like the frontal cortex, responsible for decision-making and self-control, continue developing into the mid-20s.

Adverse childhood experiences—like maltreatment or poverty—can permanently alter the brain. Abuse causes overgrowth in the fear-processing amygdala and underdevelopment of the frontal cortex, making self-regulation harder. It’s no surprise that early adversity correlates with higher rates of criminal behavior in adulthood.

This connection has influenced legal systems. In the U.S., juvenile offenders receive more lenient sentences because their still-maturing brains are considered less culpable for poor decisions.

Examples

• Childhood adversity overdevelops the amygdala and stunts the frontal cortex.
• A third of those abused as children go on to abuse their own children.
• U.S. juvenile courts acknowledge immaturity in sentencing underage offenders.

6. Culture sculpts moral and cognitive frameworks

Cultural upbringing defines how people view themselves and others. Individualist cultures, like in the U.S., emphasize personal rights, while collectivist cultures, such as in East Asia, value group harmony. These priorities manifest in the brain and moral reasoning.

For example, American brains activate more in the frontal cortex when thinking about the self, while East Asians show greater activity when thinking about group dynamics. Collectivists also take utilitarian stances; they might prioritize social stability, even if it requires sacrificing individual rights.

Such moral outlooks stem not just from social norms but from physiological responses rooted in cultural conditioning.

Examples

• Americans focus more on individual traits, while East Asians remember entire scenes.
• Collectivist cultures may approve punishing one innocent person if it prevents further harm.
• Americans resist violating individual rights, even during crises.

7. Geography influences societal traits

The environment plays a major role in shaping habits and values over centuries. For example, rice cultivation in South China required collective effort, fostering community-oriented values, while wheat farming in the north cultivated independence, leading to more innovation and higher divorce rates.

Similarly, the American individualist spirit sprang from its geography and history as a nation of immigrants. With expansion and a lack of centralized governance, settlers relied on self-sufficiency and personal responsibility, creating traditions that persist in modern values.

The natural landscape doesn’t just mold survival strategies; it impacts everything from work ethics to government policies generations later.

Examples

• Rice-growing regions emphasize cooperation, while wheat regions breed independence.
• Northern Chinese file more patents due to individualist tendencies.
• The U.S. frontier history fostered aggression and independence still seen today.

8. Brain chemistry underpins political perspectives

Differences in gray matter and brain function result in contrasting political attitudes. Liberals tend to have more gray matter in the cingulate cortex, aiding empathy and situational thinking, while conservatives often exhibit larger amygdalas, increasing sensitivity to threats.

These traits extend beyond political ideology. For example, liberals tend to identify systemic factors behind social issues like poverty. Meanwhile, conservatives are more likely to attribute such problems to personal failure, showcasing deeper emotional ties to individual accountability.

Politics, then, isn’t just a matter of opinion but reflects underlying neurological differences in cognition and fear processing.

Examples

• Conservatives’ enlarged amygdalas prompt stronger fear responses.
• Liberals’ cingulate cortices foster contextual reasoning.
• Liberals identify systemic barriers, while conservatives emphasize personal responsibility.

9. Empathy and compassion are neurologically distinct

Although empathy feels tied to compassion, these reactions activate separate brain regions. Empathy, driven by the fear-associated amygdala, links to avoiding pain, which can sometimes amplify distress without prompting action.

Compassion, however, activates the frontal cortex and inspires prosocial behaviors without triggering anxiety. Studies show that training volunteers to feel warmth, rather than empathize, resulted in greater levels of helpfulness.

True altruism seems to spring from actively avoiding empathetic distress, focusing instead on fostering intentional care.

Examples

• Feeling others’ pain activates the amygdala, driving anxiety.
• Compassion-focused training led to positive emotions and actions.
• Separate sessions showed empathy training caused negative emotions like distress.

Takeaways

1. Train compassion over empathy to foster positive, helpful emotions without distress.
2. Acknowledge the power of cultural and sensory influences on behavior to combat bias and unconscious reactions.
3. Advocate for societal systems that address the root causes of behavior, such as reducing childhood adversity and promoting social equity.