Quotes About Biology

There were two sets of encyclopedias that had sections on rats. From them we learned that we were about the most hated animals on earth, except maybe snakes and germs. That seemed strange to us, and unjust. [...] But people think we spread diseases, and I suppose possibly we do, though never intentionally, and surely we never spread as many diseases as people themselves do.

And at the root of this mental transformation are two simple biological traits—the visual and the social—that primitive humans leveraged into power.

Essentials of Physical Anthropology

the connecting fibers of the corpus callosum;

Oxytocin, the luv hormone, makes us more prosocial to Us and worse to everyone else. That's not generic prosociality. That's ethnocentrism and xenophobia. In other words, the actions of these neuropeptides depend dramatically on context—who you are, your environment, and who that person is.

Males who do extreme amounts of exercise, such as professional soccer players and runners who cover more than 40 or 50 miles a week, have less LHRH, LH, and testosterone in their circulation, smaller testes, less functional sperm. They also have higher levels of glucocorticoids in their bloodstreams, even in the absence of stress. (A similar decline in reproductive function is found in men who are addicted to opiate drugs.)

Look at systematic patterns of cultural variation as they pertain to the best and worst of our behaviors. Explore how different types of brains produce different culture and different types of culture produce different brains. In other words, how culture and biology coevolve.3 See the role of ecology in shaping culture.

In a typical study, higher testosterone levels would be observed in those male prisoners with higher rates of aggression. But being aggressive stimulates testosterone secretion; no wonder more aggressive individuals had higher levels.

The shape of women's faces changes subtly during their ovulatory cycle, and men prefer female faces at the time of ovulation.

Thus transcription factors regulate genes. What regulates transcription factors? The answer devastates the concept of genetic determinism: the environment.

in general, major stressors make people of both genders more risk taking. But moderate stressors bias men toward, and women away from, risk taking. In the absence of stress, men tend toward more risk taking than women; thus

Why else evolve the fusiform? The shape of women's faces changes subtly during their ovulatory cycle, and men prefer female faces at the time of ovulation.

Did destruction of the human amygdala lessen aggression? Pretty clearly so, when violence was a reflexive, inchoate outburst preceding a seizure.

In other cases the challenge is to appreciate how, though human physiology resembles that of other species, we use the physiology in novel ways.

Knowledge emerged about synapses, neurotransmitter-ology was born, and this idea was modified—a new memory requires the formation of a new synapse, a new connection between an axon terminal and a dendritic spine.

I think like an academic egghead, believing that if I write enough paragraphs about a scary subject, give enough lectures about it, it will give up and go away quietly. And if everyone took enough classes about the biology of violence and studied hard, we'd all be able to take a nap between the snoozing lion and lamb. Such is the delusional sense of efficacy of a professor.

Ask not what a gene does. Ask what it does in a particular environment and when expressed in a particular network of other genes

Your heart does roughly the same thing whether you are in a murderous rage or having an orgasm. Again, the opposite of love is not hate, it's indifference.

Crucially, the brain region most involved in feeling afraid and anxious is most involved in generating aggression.

It is never really the case that stress makes you sick, or even increases your risk of being sick. Stress increases your risk of getting diseases that make you sick, or if you have such a disease, stress increases the risk of your defenses being overwhelmed by the disease.

The explains why basal levels of testosterone have little to do with subsequent aggression, and why increases in testosterone due to puberty, sexual stimulation, or the start of mating season don't increase aggression either.

John Archer in a definitive 2006 review, "There is a weak and inconsistent association between testosterone levels and aggression in [human] adults, and … administration of testosterone to volunteers typically does not increase their aggression." The brain doesn't pay attention to fluctuations of testosterone levels within the normal range.

glucocorticoids in

In other words, the more genomically complex the organism, the larger the percentage of the genome devoted to gene regulation by the environment.