Behave: The Biology of Humans at Our Best and Worst by Robert M. Sapolsky

?Behave, as expressed in the author’s introduction, “explores the biology of violence, aggression, and competition, the behaviors and the impulses behind them, the acts of individuals, groups, and states, and when these are bad or good things.”

It is a monumental tome, close to 800 pages, written by a distinguished neurobiologist, primatologist, and Stanford University professor with expertise across multiple disciplines. The book has a brilliant structure and a unique narrative. What I liked most about the book is the framework Dr. Sapolsky used to explain the background of our behaviors with a reverse chronological order through certain stages. The factors that might have triggered our actions are categorized as the following:

• One Second Before: Neurobiological responses in our brains
• Seconds to Minutes Before: Sensory and priming influences.
• Hours to Days Before: Hormonal influences
• Days to Months Before: Our recent experiences.
• Adolescence and Childhood: Developmental foundations.
• Genetics, Culture, Evolution: Cultural upbringing and deep-rooted evolutionary factors.

Let’s take “smiling at a stranger” as an example. It is a complex interplay of factors such as a neurobiological response in our brain just a second before smiling, sensory influences seconds to minutes prior, hormonal states influencing our mood over hours to days, recent experiences shaping our outlook, developmental factors from childhood and adolescence, the impact of genetic and cultural background, and deep-rooted evolutionary instincts. Each layer contributes to this action. Dr. Sapolsky beautifully explores and implements this framework for various behaviors and actions…(I will try to use “smiling at a stranger”, as an example, in my key takeaways below as often as I can)

Our behaviors are not just impulsive reactions but are deeply rooted in the interconnected plain of biological, psychological, and environmental factors, with influences (on our behaviors and actions) tracing back from seconds before an action to our evolutionary past. Our behaviors defy simplistic explanations, a trap we often fall into.

The Main Idea in One Sentence:

Human behavior is influenced by myriad factors, which could be presented in a reverse chronological order that spans from immediate neural activities to deep-rooted evolutionary instincts.

Key Takeaways:

The Behavior

Immediate neural and hormonal mechanisms that are active seconds to minutes just before a behavior occurs. Different brain regions, such as the amygdala, the frontal cortex, and various hormones, interact and determine how we react to stimuli.

Our behaviors are complex to analyze, and it is very challenging to explain our actions simply.

What Happened One Second Before

In the moments right before a behavior (such as smiling at a stranger), complex neurological processes occur in our brains. These processes involve action potentials, neurotransmitters, and neural circuits. The amygdala, frontal cortex, and dopamine system are the key players in determining our social behaviors. (good and bad)

The amygdala, a key limbic structure, plays a central role not only in aggression but also in fear and anxiety. It links our emotional responses to our behaviors.

The frontal cortex is the maestro of executive functions. It regulates long-term planning, emotional control, and delayed gratification. This is where the cognitive battle between immediate and delayed benefits happens. (If there is no battle and the amygdala functions without the frontal cortex’s regulation; instant gratification wins!)

Dopamine is a critical neurotransmitter in the brain’s reward circuitry. It is linked to “anticipation of rewards”, which drives goal-directed behaviors that promise pleasure. It connects the perceived value of a reward to the effort required to achieve it. This is critical because it influences the likelihood of engaging in certain behaviors.

# As you smile at a stranger, the amygdala and frontal cortex interact in real-time, balancing emotional response and social cognition.

What Happened Seconds to Minutes Before

Behaviorists and ethologists have different views on behavior. Behaviorists emphasize the role of reward and punishment in shaping actions, while ethologists value the diversity of behavioral expressions. Subtle cues and unconscious priming have a powerful influence on our preferences and judgments. (The perceived effectiveness of a painkiller can be enhanced simply by its price tag, a placebo effect influenced by subconscious associations of cost with quality)

The impact of language on our actions is significant. This demonstrates how culture and biology together shape what we do and how we perceive the world around us. (If people are given a text including the word “ocean” a few times right before they are asked to prefer a laundry detergent, they are swayed towards a particular brand)

# Right before the smile, subconscious cues (maybe the stranger's friendly look or a pleasant environment/moment) might have primed your brain for this warm gesture.

What Happened Hours to Days Before

Hormones, especially their fluctuations, have an impact on our behaviors.

Dr. Sapolsky challenges the conventional notion that testosterone directly drives aggression. Instead, he argues that aggression is more linked to social learning and pre-existing patterns. Testosterone boosts confidence and optimism, diminishes fear, and promotes impulsive actions by dialing down prefrontal cortex activity, thus reducing our inhibitory control. It does not create new aggressions but amplifies the present aggression, especially in response to social challenges or status threats.

Oxytocin, known as the “love hormone”, is linked to nurturing and bonding behaviors. (Mother's connection to her child). However, its role is complex and context-dependent (very much!). It can foster trust and prosocial behavior within an in-group. Simultaneously, it can encourage distrust and exclusion towards outsiders (its potential dark side).

Hormones like testosterone and oxytocin do not act in isolation but are highly linked to environmental and social contexts.

# Your overall mood, influenced by hormonal activites (like a recent surge in serotonin), might have made you more inclined to smile at a stranger.

What Happened Days to Months Before

Neural plasticity and long-term changes in the brain influence our behaviors. And, our experiences shape/reshape our neural circuits.

Long-term potentiation (LTP) results in prolonged increases in signal transmission between neurons triggered by high-frequency stimulation. This process is critical for learning and memory. Solidifies the connection between neurons to form the neural basis of learning. (Seems like I was doing something good, even unknowingly, by organizing my notes on the books roughly after a month I read them..)

Neurogenesis, the creation of new neurons, especially in the hippocampus, is a very dynamic process and is influenced by various factors. Learning, exercise, estrogen, and environmental enrichment contribute to this process, while stress can hinder it.

This neuroplasticity shows that our brains (and consequently, our behaviors) are not static, and can change over mere months in an adapting response to the world around us.

A “different world” indeed fosters a “different worldview”.

Brain’s flexibility shows that our experiences shape who we are (Literally in a physical and neural way)

# Recent positive social interactions or fulfilling experiences might have prepared you to feel more open and smile at a stranger.

What Happened During Adolescence

The adolescence period of life is when we are significantly more risk-taking and novelty-seeking. The ongoing maturation of the frontal cortex and the heightened sensitivity to “peer influence” drive this.

“Peer influence” is mainly driven by the need to belong and the pain of rejection (often more so than in later life stages). Rejection is felt more acutely during these years, which amplifies the need for social acceptance.

Empathy during this stage is profound. Adolescents often deeply feel with the other, sometimes too much that the line between self and other gets blurred.

During adolescence, the brain goes through a unique phase where emotions are heightened, social interactions become more important, and decision-making skills are still developing. This is a critical time for shaping behaviors that will stick with individuals into adulthood.

# The social skills learned and developed during your adolescence could make you more inclined to smile at a stranger.

What Happened During Childhood and Babyhood

Early life experiences like childhood and babyhood significantly influence our future behaviors. John Bowlby’s attachment theory emphasizes the necessity of love, warmth, affection, responsiveness, and reliability from our caregivers. The absence of these often leads to anxious, depressed, poorly attached adults. This indicates the lasting impact of early emotional environments on our adulthood.

Childhood adversity can impair learning, memory, and frontal cortex maturation by inhibiting Brain-Derived Neurotrophic Factor (BDNF) through glucocorticoids.

Witnessing violence and bullying can predict both current and future aggressive behavior.

Parenting styles (authoritative/authoritarian/permissive) not only shape behaviors but also influence how children perceive and interact with the world, as seen in differing cultural interpretations of leadership and social dynamics. (Collectivist vs. individualist cultures)

Near-term fetuses can hear, taste, and remember stimuli from outside the womb, which influence their preferences post-birth.

There is unanimous agreement in psychological literature: Childhood matters deeply! It sets the stage for who we become as adults.

What Comes from Our Genes

Genes play a pivotal role in underpinning our behaviors as well. However, their influence is limited and context-dependent. They do not dictate our future, as depicted in popular genomics.

Genes do not operate in isolation. 95% of our DNA is noncoding! A significant portion is dedicated to regulating gene expression in response to environmental factors. These environmental factors can influence gene expression over days, or even lifetimes.

As living things become more complex, a greater part of their genetic information is dedicated to how their environment affects how their genes work.

The way we behave as humans is affected by both our genes and the environment we live in. These two things work together to shape our behavior.

What Comes from Culture (Centuries to Millenia Before)

Culture matters.

How gender equality is practiced in different countries can affect how well students perform in math. Various research results support this correlation. Social and cultural factors influence capabilities.

Examination of collectivist versus individualist cultures demonstrated that societal values impact a wide range of behaviors, from problem-solving approaches to interpersonal relationships.

On the age-old debate between Hobbes and Rousseau on the nature of human society, Dr. Sapolsky suggests a reality that incorporates elements of both thinkers’ views.

Again, there is a dynamic interplay between our biology and culture. Our brains shape our cultures, which in turn shape our brains, which in turn shape our culture…so on. (Dr. Sapolsky calls it “co-development”)

# Your genetic tendencies for sociability (and if combined with a cultural background that values friendliness) likely might have influenced your inclination to smile at a stranger.

Conclusion

Human behavior is complex, and oversimplification is dangerous. Dr. Sapolsky advocates for a multi-disciplinary approach to understanding behavior, combining insights from biology, psychology, sociology, and other fields throughout the entire work. This comprehensive exploration and pov challenge us to reconsider our understanding and perceptions of our actions and behaviors, including the ones as seemingly simple as “smiling at a stranger”. This perspective is so invaluable in my opinion in an era where quick judgements and decisions are made with oversimplified approaches. Our behaviors are not one-dimensional but are results of complex interplay of multiple dimensions.

Also, as an engineer, I found Dr. Sapolsky’s “destruct-and-then-reconstruct- approach very relatable and comprehensible. It is a unique framework for dissecting and understanding the components of behavior.

I have not captured here but the book has much more, with a deeper analysis of human behavior and practical recommendations to consider in various facets of our societies and our daily lives. Dr. Sapolsky’s Behave is much more than an academic exploration of human biology, it is a compelling and enlightening narrative of our “nature”.

Kaan Demiryurek

18 January 2024

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