Quotes from Robert M. Sapolsky

If their heart rate increases a lot (a peripheral indicator of anxious, amygdaloid arousal), they are unlikely to act prosocially in the situation. The prosocial ones are those whose heart rates decrease; they can hear the sound of someone else's need instead of the distressed pounding in their own chests.fn9,48

For starters, circulating oxytocin levels are elevated in couples when they've first hooked up. Furthermore, the higher the levels, the more physical affection, the more behaviors are synchronized, the more long-lasting the relationship, and the happier interviewers rate couples to be.

A critical realization roared through the research community: the physiological stress-response can be modulated by psychological factors. Two identical stressors with the same extent of allostatic disruption can be perceived, can be appraised differently, and the whole show changes from there.

THE DELAYED MATURATION of the frontal cortex suggests an obvious scenario, namely that early in adolescence the frontal cortex has fewer neurons, dendritic branches, and synapses than in adulthood, and that levels increase into the midtwenties. Instead, levels decrease.

Neuropsychologists are coming to recognize that there is a specialized subset of long-term memory. Remote memories are ones stretching back to your childhood—the name of your village, your native language, the smell of your grandmother's baking. They appear to be stored in some sort of archival way in your brain separate from more recent long-term memories. Often, in patients with a dementia that devastates most long-term memory, the more remote facets can remain intact.

The picture is complicated further—AIS individuals raised female have higher-than-expected rates of being gay, and of having an other-than-female or neither-female-nor-male-sex/gender self-identification.

The subject is also fascinating because of the nature of the revisionism—neuroplasticity radiates optimism. Books on the topic are entitled The Brain That Changes Itself, Train Your Mind, Change Your Brain, and Rewire Your Brain: Think Your Way to a Better Life, hinting at the "new neurology

Young humans are like chimps—six-year-olds not only prefer to be with kids like themselves (by whatever criteria) but readily say so. It isn't until around age ten that kids learn that some feelings and thoughts about Thems are expressed only at home, that communication about Us/Them is charged and contextual.60

Greene calls "the Tragedy of Commonsense Morality" is shown by the fact that most intergroup conflicts on our planet ultimately are cultural disagreements about whose "right" is righter.

What's a heritability score? "What does a gene do?" is at least two questions. How does a gene influence average levels of a trait? How does a gene influence variation among people in levels of that trait?

These are crucially different. For example, how much do genes have to do with people's scores averaging 100 on this thing called an IQ test? Then how much do genes have to do with one person scoring higher than another?

the fetal brain generates far more neurons than are found in the adult.

Thus, oxytocin and vasopressin facilitate bonding between parent and child and between couples.fn10 Now for something truly charming that evolution has cooked up recently. Sometime in the last fifty thousand years (i.e., less than 0.1 percent of the time that oxytocin has existed), the brains of humans and domesticated wolves evolved a new response to oxytocin: when a dog and its owner (but not a stranger) interact, they secrete oxytocin.

When a rat wins a fight, the number of testosterone receptors increases in the ventral tegmentum and accumbens, increasing sensitivity to the hormone's feel-good effects.10

But in reality the brain is about circuits, about the patterns of functional connectivity among regions. The growing myelination of the adolescent brain shows the importance of increased connectivity.

the logical strategy in one-round Prisoner's Dilemma is to defect. Cooperation flourishes when games have an uncertain number of rounds, and with the capacity for our reputations to precede us. Groups, by definition, have multiple-round games and the means to spread news of someone being a jerk.

An emptiness comes from this combination of over-the-top nonnatural sources of reward and the inevitability of habituation; this is because unnaturally strong explosions of synthetic experience and sensation and pleasure evoke unnaturally strong degrees of habituation.

our frequent human tragedy is that the more we consume, the hungrier we get.

For the vast majority of beasts on this planet, stress is about a short-term crisis, after which it's either over with or you're over with. When we sit around and worry about stressful things, we turn on the same physiological responses—but they are potentially a disaster when provoked chronically

What was an unexpected pleasure yesterday is what we feel entitled to today, and what won't be enough tomorrow.

Moving beyond mere correlation, if you lesion the amygdala in an animal, rates of aggression decline. The same occurs transiently when you temporarily silence the amygdala by injecting Novocain into it. Conversely, implanting electrodes that stimulate neurons there, or spritzing in excitatory neurotransmitters (stay tuned), triggers aggression.4

Stick recording electrodes into numerous species' amygdalaefn9 and see when neurons there have action potentials; this turns out to be when the animal is being aggressive.fn10 In a related approach, determine which brain regions consume extra oxygen or glucose, or synthesize certain activity-related proteins, during aggression—the amygdala tops the list.

If genes strongly influence average levels of a trait, that trait is strongly inherited. If genes strongly influence the extent of variability around that average level, that trait has high heritability.

contemporary studies show that the worst stress-related health typically occurs in middle management, with its killer combo of high work demands but little autonomy—responsibility without control.