Hormones influencing the sensitivity of the person to environmental stimuli.

Fossey, Fossey, you cranky difficult strong-arming self-destructive misanthrope, mediocre scientist, deceiver of earnest college students, probable cause of more deaths of the gorillas than if you had never set foot in Rwanda, Fossey, you pain-in-the-ass saint, I do not believe in prayers or souls, but I will pray for your soul, I will remember you for all of my days, in gratitude for that moment by the graves when all I felt was the pure, cleansing sadness of returning home and finding nothing but ghosts.

I had never planned to become a savanna baboon when I grew up; instead, I had always assumed I would become a mountain gorilla.

If I had to define a major depression in a single sentence, I would describe it as a "genetic/neurochemical disorder requiring a strong environmental trigger whose characteristic manifestation is an inability to appreciate sunsets.

The gigantic challenge is the magnitude of the individual differences in the optimal set point for "good stress." For one person, it's doing something risky with your bishop in a chess game; for someone else, it's becoming a mercenary in Yemen.

Importantly, rather than promoting aggression, testosterone promotes whatever is needed to maintain status when challenged.

There's the complex categorization of low warmth/high competence. This is the hostile stereotype of Asian Americans by white America, of Jews in Europe, of Indo-Pakistanis in East Africa, of Lebanese in West Africa, of ethnic Chinese in Indonesia, and of the rich by the poor most everywhere. It's the same low-high derogation: They're cold, greedy, clannish - -but, dang, they're sure good at making money and you should go to one who is a doctor if you're seriously sick.