Evolutionary biologists know why humans spend disproportionate energy on negative thoughts compared to positive: Teasing out threats, real or perceived, is a basic tool of survival.

Three a.m. isn’t the only time negative thoughts seize us. Even when we’re at ease, evolutionary instincts cause us to seek out whiffs of threat, real or imagined. Commonly called the human "negativity bias," we train our mental energy on perceived danger, releasing cortisol and triggering flight or fight instincts that have served mammals from the beginning.

Donald Trump is a master of manipulating people with negativity and fear. He built a naked tribalism movement on us vs. them vitriol, with immigration, crime, race, and “vermin” of different political views topping his greatest hits. His running mate JD Vance’s negative divisiveness is next level: Hillbilly vs. Silicon Valley, parent vs. childless, cat ladies vs. those with a proper stake in democracy. Almost overnight, Vance served up new antagonisms between voter categories we didn’t even know existed.

Stewing in frustration over Kamala Harris’ meteoric rise, Trump can hardly restrain his jealousy. In a revolting pique of petty, confirming that he would destroy America for his own personal gain, Trump insulted American hostages’ release from Russia, praising Putin instead. He then drooled giddy when the stock market tanked last week, clucking, “TRUMP CASH vs. KAMALA CRASH!”........

© Salon