What Influences Behaviour?

Behaviour is unique to each individual, yet it has its roots in society and culture that define the modern world. Additionally, it is a result of many factors. A number of complexes ranging from the brain’s chemistry to social and environmental conditions affect human behaviors. Moreover, these tendencies to behave in a particular manner have evolved over thousands of years, influenced and affected by human history and different civilizations. 

Robert Sapolsky’s Behave (2017) delves deep into how human conditioning results in different human behaviours.

Culture, History, And Biology

To understand human behavior, understanding human biology is vital. The human brain is perhaps the oldest, and the most wondrous part of the anatomy, and the way the brain works can be linked to evolutionary factors. Every human act first begins as a reaction in the brain. In fact, even the basic instincts such as the fear of dying are processed by the brain’s oldest parts that have been essentially inherited.

For example, when a person shoots a gun, it is the very basic, inherited, evolutionary, and emotional trigger in the brain that creates the impulse to pull the trigger. In addition to these factors, the brain processes sensory information – visual and auditory – from its surrounding environment to trigger the behavior. If we consider a war zone, it is the heightened sense of danger in the surroundings to makes people act aggressively. These biological behavioral responses are also influenced by human history, society, and culture.

History, society, and culture shape behavior right from childhood. People from different societies will react differently to situations. For example, people who are used to violence in their society and culture tend to be generally more violent in nature.

Additionally, ancestral ecology and geography also affect behaviour. Considering all these factors that affect human behaviour, we can see that behaviour is an extremely complex phenomenon that needs has answers in different disciplines.

Behave by Robert M Sapolsky - Book Review
Behave by Robert M Sapolsky – Book Review

How The Brain Controls Aggression

When it comes to processing and controlling aggression, the amygdala and the frontal cortex of the brain are involved in the split-second decisions that lead to aggressive behavior.

The amygdala, located in the cerebral cortex (the biggest region of the brain) controls fear and aggression. Experiments conducted have shown brain activity in the amygdala when subjects were shown images stimulating fear or anger.

In 1966, Charles Whitman killed his mother and his wife before he went on a shooting rampage at the University of Texas. Additionally, he had left a note near his wife’s body stating that he couldn’t ‘rationally specify any reason for his act’.

While his motives were not clear, the autopsy conducted revealed a tumor pressing his amygdala. The autopsy made it clear why a happily married man would suddenly behave in such a violent manner. Prior to his act, he had even complained to his doctor of having violent impulses and headaches. It was the neurological changes caused by his amygdala that resulted in his behavior.

The frontal cortex of the brain, on the other hand, controls impulsiveness and regulates emotions such as aggression. The case of Phineas Gage shows the link. In 1848, Phineas Gage was working at a Railroad Company in Vermont. Gage met with an unfortunate accident where a sudden explosion sent an iron rod through his skull piercing his frontal cortex. Shockingly, he survived the accident and lived for more than a decade after the accident.

After recovery, while gage showed normal brain functioning in areas of intelligence, cognition, perception, memory, and language, according to his friends, he was no longer the same person he was before. He lost respect for social conventions, started swearing, lying, ignoring sound advice, and became impulsive. This proved that the frontal cortex is vital to regulating aggression and determining appropriate behavior.

A number of case studies of violent psychopaths and criminals have shown that their behaviors have been results of either having injured the frontal cortex or having lower activity in the region.

Behaviour Is Shaped By The Environment

The five senses are constantly sending information they receive from the environment. This information or sensory cues, shape human behavior too.

Visual cues alter people’s perceptions. Cues such as faces, and even skin color can change one’s attitude towards others. When images were shown to white participants for 1:10th of a second, it was observed that the activity in their amygdala increased when they saw images of people from other ethnic backgrounds. Furthermore, when the duration of the images of ethnically different people was increased, their frontal cortex rationalized their initial responses triggered by the amygdala. Naturally, for non-racists, the response of fear from the amygdala typically gets quelled. 

However, these findings of the initial amygdala responses are intrinsic to why longer sentences for the same crime are given to a stereotypical African face than to a white one. These findings have also helped many defense attorneys change their strategies such as giving male black clients chunky glasses to make their faces more associable with nerd whites than black criminals.

Cues that are auditory can similarly generate feelings of fear.

Another similar experiment showed that when researchers played rap music (identifiable with African American culture), and death metal music, associated with whites while showing participants images, the rap music showed increased activity in the amygdalae of the participants while death metal had the opposite effect.

In addition to visual and auditory cues, behaviors are also affected by one’s immediate social contexts. It is found that men tend to be more akin to risks while they are near women, choose luxury items than buy daily essentials around them. This generosity is seen because, in the company of women, males are unconsciously giving mating signals.

How Hormones Influence Behaviour

The relationship between behavior and hormones is quite complex. Hormones are chemicals that form in different glands in the body and when discharged into the bloodstream, affect different parts of the human brain.

Testosterone is produced in the male testes and the female ovaries, and though isn’t a direct cause of aggression, studies have revealed links between the two. It is a known fact that castration can reduce the level of aggression among males. Therefore, even if sex offenders are punished by castration, one has to consider the factor of context, which also affects behaviors.

 According to some studies, male prisoners have higher levels of testosterone if they exhibit aggression. Thus, contrary to belief, it is a higher level of aggression that increases levels of testosterone secretion and not vice-versa.

Ironically, the amygdala has a high number of testosterone receptors, and thus, increased levels of testosterone can lead to aggression, but only if an individual is predisposed to aggressive behavior.

Similarly, oxytocin – which is associated with positive emotions and trust – inhibits amygdala activity. Hence, oxytocin is known to correlate with pro-social behaviors.

Studies involving economic games showed subjects having higher oxytocin levels viewing others as trustworthy. Considering trust, lower oxytocin levels should have made the subjects in the study distrust deceitful players. However, as the game progressed, the subjects, nevertheless, trusted the deceitful players. Oxytocin too works within the boundaries of context. The subjects exhibited higher levels of trust only when the players were in front of them in the same room.

The Impact Of Childhood Experiences

About 85% of the human brain develops within the first two years of life. The other 15% that includes behavioral development develops as the child grows. The frontal cortex of the brain develops much later on, closer to the mid-’20s.

The adolescent years of a human are extremely critical for behavior development. It is during the adolescent years when the frontal cortex (still undeveloped), can lead to risk-taking, impulsiveness, and even spike up violent traits. Thus an undeveloped adolescent frontal cortex can negatively influence behaviors.

This knowledge has indeed seen some countries like the US treat younger offenders more leniently, with the Supreme Court ruling in a landmark case that it is illegal to sentence juveniles with life sentences without parole.

Additionally, a difficult childhood can cause increased levels of violence among youngsters for life. The brain’s neural plasticity – or the ability to absorb information – is much faster among children than in adults. Thus repeated negative experiences or childhood abuse can cause these children to themselves abuse their own children in adulthood.

Any adversity such as violence or poverty experienced in childhood can cause overdevelopment in the amygdala and underdevelopment in the frontal cortex. Therefore, since the frontal cortex is vital to inhibiting the amygdala’s impulsiveness, an overdeveloped amygdala with an underdeveloped frontal cortex result in violent tendencies in later life and poor behavioral regulation.

Cultural Factors And Societal Behaviour

In addition to neurobiology, cultural factors are equally intrinsic to human behavior. For example, if Honduras sees four hundred and fifty times more murder cases than Singapore does, it is evident that cultural conditioning also plays a vital role.

If we consider different cultures such as the individualistic US and the collective culture of East Asia, we can see that culturally, the people of the United States tend to focus on personal achievement and individual rights. On the other hand, collective cultures focus on the needs of the group before individual ones.

Studies in brain activity have shown that when Americans are shown pictures of themselves, their frontal cortices activate faster than when they are shown pictures of relatives, an impulse that isn’t as strong in East Asians.

Cultural differences also affect sensory processes. For example, when East Asians are shown a picture of a person standing alone in a complex scene, they are more likely to focus on the surrounding scene than the individual. Americans would focus more on the details of the individual.

Cultural differences also result in varied moral systems. In collective cultures, utilitarian moral stances are more common because they value the needs of the many. Therefore, they also place more value on the greater good, especially in criminal justice. These cultures would be more willing to arrest innocent people if it would be the means to stop a riot. Contrarily, in individualistic cultures, individual rights would take precedence, and imprisonment of the innocent without due process would go against societal norms.

The Influence Of Local Ecology And Geography

The development of collective or individualistic cultures can be attributed to the surrounding environment, geography, and local ecology, especially since the development of culture is a slow, but sure centuries-long process.

For example, East Asian countries are predominantly rice-cultivating agricultures. Growing rice is a collective communal labor activity, as opposed to growing wheat, like in North China, where rice is difficult to grow. It is observed that in the North china regions, divorce is more common than in other surrounding rice-growing regions. Additionally, the individualistic wheat-growing culture has resulted in more patents filed in the northern regions.

The United States, being a predominantly immigrant nation, sees immigrants who are essentially seen as outcasts, criminals, or second-class citizens in their native countries. America is perceived as a place to start life afresh, most because immigrants see it not only as a way out of their original social contexts but also as a new geographical environment. If we consider the geographical context of colonial America, we can see that the country needed immigrants to develop and civilize the land, especially for growth. This individualistic, self-reliant, and even aggressive sense of development prevailed as long-standing character traits; traits that are seen in many southern states even today.

America has historically been rural and pastoral geography, making it tougher for the center to implement laws. This made people take law into their own hands, increasing instances of violence and making violent traits more common, even to this day.

Neurobiology, Political Views And Morality

Morality and political views are also influenced by neurobiology. In fact, there is a correlation between the brain and whether a person has a conservative or political perception. A study that interviewed people of both these political views, saw both sides answer that the roots of poverty lay in the laziness of the poor. However, when the group was asked to rationalize their perceptions, it was found that the liberals gave a situational response that the odds were stacked against the poor.

A similar mentality can be seen when different people are presented with non-political topics. For example, both, liberals and conservatives initially blamed the clumsiness of a dancer who falls while dancing, however, given time, the liberals were able to rationalize that perhaps the difficulty of the steps could also be blamed.

Additionally, studies have found neurobiological differences between liberals and conservatives. It is observed that liberals possess more grey matter in the areas of the brain that controls empathy – the cingulate cortex. Contrarily, conservatives have a heightened response to fear due to their enlarged amygdalae, making them more anxious in situations that are risky.

The brain’s neurobiological connections are also responsible for morality. For example, telling a lie against better judgment leads to activity in the frontal cortex. The act of hiding the truth puts pressure on the frontal cortex to work at full throttle, as strategic deceit is far more difficult for the brain than to simply tell the truth.

On the other hand, honest individuals’ frontal cortices do not activate during an opportunity to deceive at all simply because they don’t consider deception at all, and thus their frontal cortices do not need to stress themselves out at all.

The Differences Between Empathy And Compassion

Let’s begin with an example. When we see someone prick their finger with a needle, the responses that generate from us are purely physical. Our own hands would tighten up, indicating that empathy is connected with avoiding physical pain.

 The Anterior Cingulate Cortex or the ACC links both the amygdala and the frontal cortex. It gets activated when we see others’ pain. It helps the brain learn fear from observed bad experiences, indicating that empathy actually results out of self-preservation than compassion for others’ pain.

How empathetic one feels depends on sensory factors. We know that visual perceptions of different ethnic people can trigger the fear-inducing amygdala to activate, thus making them less empathetic. Now consider how empathy is affected if the person who pricked his finger is racially different.

A study conducted on the relationship between empathy and compassion found that while both are perceived as closely associated, they have completely different origins in the brain and activated b different reactions to other peoples’ pain. 

In the study, two parallel training sessions were conducted. The study group was asked to feel the pain of a suffering subject. The activation of the amygdala that followed resulted in negative feelings and anxiety among the group. In the second training, they were asked to feel the warmth and completely avoid empathizing with the distressed subject. This time, instead of the amygdala, the frontal cortex was activated and the group felt pro-social, positive feelings proving that behaviors leading to empathy and compassion have completely different connotations.


The study of human behaviour is an old endeavour that seems to get more complex as research delves deeper into it. However, it is clear that behaviour is an extremely complex phenomenon that is influenced and affected not only by the environment and society but also by historical conditioning, geographical implications and even the smallest neurobiological responses seen in different parts of the brain.