Part 2. Wired for Survival
When biology overrides our better judgment
Previous I talked about why it’s not always easy to get along with others. We might want to believe we’re rational creatures. That our thoughts are measured, our reactions reasonable, our judgments fair. But when I find myself arguing with my husband yet again despite my better intentions, or procrastinating over an email I haven’t answered, I’m reminded: evolution had other priorities.
The human brain, impressive as it is, wasn’t designed for peace of mind. It was designed for survival.
To understand why being human—and being around other humans—can feel so maddeningly difficult at times, it helps to start not with psychology or culture, but biology. We are not blank slates. We are anxious social creatures shaped by millennia of danger, scarcity, and social dependence. Our brains can feel like old mainframes running COBOL, highly dependable at running old scripts, but not able to properly respond to today’s changed demands.
Imagine, for a moment, two early humans walking the savanna. One hears a rustle in the brush and keeps strolling. The other jumps, heart pounding, adrenaline surging. Nineteen times out of twenty, the anxious one overreacts. But the one time it’s a lion? The anxious one lives.
We’re descended from the jumpy ones.
This bias toward caution is no accident—it’s a survival feature. The fight-or-flight response we associate with modern stress was once a literal lifesaver. Faced with real danger, our ancestors needed bodies ready to run or fight. Stress hormones like cortisol and adrenaline surged to redirect energy, sharpen focus, and keep them alive.
But here’s the catch: our biology hasn’t caught up to our reality.
The rustling in the bushes has been replaced by a thoughtless comment, an unanswered request for help, and the mild dread of a 3 pm meeting. The stakes are different, but the brain’s reaction is often the same. The heart races, the muscles tense, the breath quickens. Our inner alarm systems don’t distinguish between a predator and a passive-aggressive comment.
This mismatch shows up in small, persistent ways. A partner or coworker’s offhand remark loops in our minds for hours. One critical review outweighs a dozen compliments. We find ourselves inexplicably exhausted after a perfectly ordinary day.
This is what neuroscientists call the negativity bias, and it's deeply woven into our neural circuitry. In evolutionary terms, it made sense. Missing a threat could be fatal; missing something pleasant was not. So we learned to notice, remember, and anticipate the negative far more than the positive. Our brains became attuned to bad news and wary of uncertainty. That tendency didn’t fade when the lions left.
Even our social behaviors bear the imprint of survival. We evolved in small, tight-knit groups where acceptance meant safety and rejection spelled danger. Conflict, exclusion, or disapproval were not just unpleasant—they were existential threats. No wonder we are so sensitive to social cues, so reactive to perceived slights, so inclined to seek out sameness and defend against difference. Tribalism isn’t a modern invention; it’s an ancient reflex.
We like to think of ourselves as reasonable and fair, but the truth is, we’re fast to judge, slow to trust, and exquisitely alert to the smallest shifts in status or approval. We gossip to bond, compare to belong, and withdraw or lash out when stress tips us past our limit. And then, often, we judge ourselves for it.
But maybe there’s room for a little compassion here. We were shaped by a world that no longer exists—and yet we still carry its imprints in our nervous systems, our conversations, and our quietest moments of self-doubt.
It’s a not unlike how our evolutionary drive to eat for survival clashes with the abundance of food in today’s world—leading to a reality where three-quarters of us are overweight or obese.
This isn’t an excuse. But it is an explanation.
We still have a choice in how we respond, in whether we pause before reacting, in whether we offer grace—to ourselves and others. But those choices come more easily when we understand what we’re up against: not a personal failing, but an ancient pattern.
We’re wired for survival. And surviving today means learning how to live with—and sometimes gently override—those old wires.
This post is part of the “Unwiring” series on Substack, exploring how our nervous system shapes modern life—and how we can shift from reactivity to choice. Catch up on the previous posts here.