Behave

by [Robert Sapolsky]

Full notes

Causes of our behavior

• Brain
  • Hippocampus
  • Amygdala
    • most involved when feeling afraid / anxious and in generating aggression
    • default is to trust, amygdala learns vigilance and distrust (which have to be unlearned actively)
    • stress makes it easier to learn smth associated with fear
    • help to remember details, which triggers aggression
  • Neuroplasticity
    • experience, health, and hormone fluctuations can change the size of parts of the brain in a matter of months. Experience can also cause long-lasting changes in the numbers of receptors for neurotransmitters and hormones, in levels of ion channels, and in the state of on/off switches on genes in the brain
    • neuron influence trade-off - its “potential” is constant, it can be spread across more target neurons (but weaker)
• Hormones
  • Testosterone
    • does not create aggression directly, it amplifies and exacerbates preexisting tendencies
    • (primates) rise when a dominance hierarchy is initially formed or being reorganized
    • (humans) rise during sports challenge (individual or team competitions), increases among winners
    • even watching your “team” - it is about dominance, group identification
    • when rises after a challenge, it activates behaviors needed to maintain status (not necessary aggression)
  • Oxytocin
    • (female mammals) central to nursing (to want to nurse a child and remember which one is theirs)
    • activates prosocial behaviors & released when experiencing prosocial behavior
• Genes
  • Genes are relevant to .. basically everything. They regulate hormones, neurotransmitters, and their receptors. Genes are a low-level layer of configuration and orchestration
  • not all of the DNA form genes, only 5% of it represents coding genes. Rest is inactive, however, it is like meta code, which decides which genes should be activated or deactivated; before each gene there is a promoter (on/off switch) which activates given transcription factor.
  • The later a particular brain region matures, the less it is shaped by genes and the more by environment
  • Genes can work in a particular environment, .. don’t ask what a gene does; ask what it does in a particular environment, see MAO-A - Having the low-activity version of MAO-A tripled the likelihood (of antisocial behavior) but only in people with a history of severe childhood abuse
  • there is something like epigenetically mediated mechanisms of inheritance - after all, Jean-Baptiste Lamarck wasn’t so wrong about his famous heredity claims (this is still very controversial subject)
• Aspects of behavior
  • Risk-taking
    • major stressors make people of both genders more risk-taking
    • moderate stressors bias men toward, and women away from, risk-taking
    • In the absence of stress, men tend toward more risk-taking than women
    • adolescence is mostly about taking a risk and seeking new experiences
  • Us / Them
    • Oxytocin exaggerates Us/Them-ing (forgiving Us more readily than Them)
    • most exquisitely happy moments of my life have come from feeling like an Us, feeling accepted and not alone, safe and understood, feeling part of something enveloping and larger than myself, filled with a sense of being on the right side
    • “Belonging is safety”
• Children
  • when experiencing childhood adversity amygdala can develop the ability to inhibit frontal cortex
  • exposure to violent media can increase aggression levels soon after
  • heavy childhood exposure to media violence predicts higher levels of aggression in young adults HOWEVER there are no evidence that extremally violent people (mass shooters) are because of media aggression
• Culture
  • individualism / collectivism
    • US/Europe vs East Asian: Americans are more likely than East Asians to remember times in which they influenced someone; conversely, East Asians are more likely to remember times when someone influenced them and mesolimbic dopamine systems activate in European Americans when looking at excited facial expressions; in Chinese, when looking at calm expressions
    • correlation of individual (northern China) vs collective farming with individualist vs collectivist culture markers
    • (Ruth Benedict, 1946), collectivist cultures enforce with shame, while individualitic cultures use guilt
  • inequality
    • stratified cultures might be a good survival strategy: when times are tough, the unequal access to wealth becomes the unequal distribution of misery and death (another strategy: hunter-gatherers pick up and move)
    • it is feeling poor (comparing to other people) what’s predicts poor health
    • beeing exposed on social inequality raises violence levels within your (lower) class
  • population density
    • it exaggerates preexisting social tendencies, high-density makes aggressive individuals more aggressive (similar to testosterone, alcohol, media violence), it also makes unaggressive individuals more shy and fearful
  • politics
    • people become more conservative when tired, in pain or distracted with a cognitive task, or when blood alcohol levels rise.
    • “rightists” statistically are more likely to respect hierarchy, don’t like new ideas, take given circumstances as a threat
    • “conservatism” associated with an enlarged amygdala (threat perception)
    • “liberalism” associated with larger amounts of gray matter (empathy) and higher amygdala activation for disgust and taking risk
• Religion
  • desert cultures -> monotheistic religions, rain forest cultures -> polytheistic religions
  • once cultures get large enough that anonymous acts are possible, they start inventing moralizing gods
• Evolution
  • is not gradual (S. J. Gould) - there is some buffer require for changes to start occurring, after some events it goes faster
• Moral judgments
  • we detect better violations of social contracts, which results in bad outcome. We also search harder for causality in such “bad” cases
  • different brain regions are used for own moral failings than in those for other people
  • we judge ourselves by motives vs others by results (actions)
  • gossip - we use it in 2/3 of all conversations, mostly in a negative way - can be viewed as a way for weak to fight against powerful
  • we do “right” things because it is easier (lying requires more energy and thinking)
  • ACC is about error detection Feeling someone else’s pain can be more effective for learning than just knowing that they’re in pain. At its core the ACC is about self-interest, with caring about that other person in pain as an add-on
• Language
  • a metaphor might trick the brain because of literal “understanding” As a result, we are actually pretty lousy at distinguishing between the metaphorical and literal, at remembering that “it’s only a figure of speech”—with enormous consequences for our best and worst behaviors.