Last week I screamed at a spider.
It was small—smaller than my thumbnail. It was sitting on the bathroom wall doing nothing. It posed no threat to me whatsoever. But when I saw it, my heart raced, my body jerked backward, and a sound came out of my mouth that I am embarrassed to describe.
An hour later, I got into my car and drove to work at 80 kilometers per hour, surrounded by other metal boxes traveling at similar speeds, separated from death by a few centimeters of painted lines on asphalt. I felt nothing. No racing heart. No jerking backward. I turned on the radio and thought about lunch.
This makes no sense.
The spider has never killed anyone I know. The car has killed thousands. In Bangladesh alone, road accidents claim over 20,000 lives every year. I do not know the statistics for spider-related deaths, but I am certain the number is close to zero. By any rational calculation, I should fear the car infinitely more than the spider.
But fear is not rational. Fear is ancient. And my ancient brain does not know about cars.
I have been thinking about this mismatch for years. About how we carry stone-age minds in a digital world. About how the things that terrify us are rarely the things that kill us.
Our ancestors lived in a world where spiders could be deadly. Not all of them, but enough. A bite from the wrong spider meant infection, fever, death. There were no hospitals in the paleolithic era. No antibiotics. A small creature with eight legs could end you. So evolution built a brain that screamed DANGER whenever it saw erratic, crawling movement. The people who feared spiders survived. The people who didn’t, died. Over millions of years, spider-fear became wired into our nervous system.
The same is true for snakes, for heights, for darkness. These were real threats for most of human history. Our brains learned to fear them automatically, without thinking, without calculation. The fear came first. Thought came later—if it came at all.
But cars are new. They have existed for barely a century. Evolution works slowly. It has not had time to build car-fear into our nervous system. When I sit in a car, my ancient brain sees nothing alarming. The seat is comfortable. The movement is smooth. I feel in control. My hands are on the wheel. My foot is on the pedal. The illusion of agency is complete.
This is the cruelest trick of modern life. The things that will actually kill us feel safe. The things that will not kill us feel terrifying.
I know a man who refuses to fly. He has turned down jobs, missed weddings, avoided entire continents because he cannot board an airplane. His fear is absolute. Yet he drives every day on highways where his odds of dying are vastly higher. The statistics mean nothing to his limbic system. His brain knows that humans are not meant to be in the sky. It does not know that humans are not meant to hurtle through space in metal boxes at 120 kilometers per hour.
The modern world is full of invisible killers that our brains cannot detect.
Air pollution kills millions every year. But we cannot see it. We cannot smell it most of the time. Our ancestors never encountered anything like it, so we have no instinct to fear it. We breathe it in without alarm.
Processed sugar damages our bodies slowly and surely. But our ancestors craved sweetness because it was rare and indicated nutrition. We have no mechanism to fear the thing we are built to desire.
Chronic stress destroys our hearts and minds. But stress responses were designed for short-term threats—the tiger that might attack, the rival who might strike. We have no defense against stress that lasts for years.
These are the real dangers. Not spiders. Not snakes. Not the darkness that frightened our great-great-grandparents. The real dangers are statistical, invisible, slow-moving. They kill through accumulation, not attack. Our stone-age brains have no category for them.
I think about my grandmother. She was afraid of many things—spirits, curses, the evil eye. She performed rituals to protect against threats that did not exist. Meanwhile, she cooked with oil that clogged her arteries and never thought twice about it. Her fears and her dangers never overlapped.
Are we any different? We install home security systems while eating ourselves into heart disease. We worry about strangers while ignoring the cigarettes we smoke. We fear plane crashes that almost never happen while driving drunk on weekends. We have inherited a threat-detection system that is worse than useless in the modern world. It is actively misleading.
What should we do with this knowledge?
I am not sure we can rewire our instincts. The spider will always make me jump. The car will always feel safe. Millions of years of evolution cannot be undone by reading statistics.
But perhaps we can build a second system on top of the first. A conscious system that knows what the instincts do not. A system that says: yes, you are afraid of the spider, and no, the spider will not hurt you. Yes, you feel safe in the car, and no, the car is not safe.
This requires effort. It requires overriding feelings with facts. It requires accepting that our gut reactions are not trustworthy guides to modern danger.
I have started doing this, in small ways. When I drive now, I try to remember that I am doing something dangerous. Not to make myself afraid—fear while driving would be counterproductive—but to make myself careful. To remind myself that the comfort I feel is an illusion. That the painted lines are not walls. That the other drivers are fallible humans, not predictable machines.
And when I see a spider, I try to let the fear pass without action. I watch my heart race and my body tense, and I wait. The spider does nothing. The fear fades. I realize, again, that my instincts lied to me.
This is the strange work of being human in the modern world. Learning to distrust the ancient voice inside that says danger and safety. Learning that the voice evolved for a world that no longer exists. Learning to think past the fear to the fact.
The spider on my bathroom wall is still there. I have decided to let it stay. It eats mosquitoes, which carry diseases that actually kill people. The spider is my ally. My brain just doesn’t know it yet.
And tomorrow I will get in my car again. I will feel safe again. But somewhere in my mind, I will hold the knowledge that the feeling is wrong.
I cannot change my instincts.
But I can learn not to trust them.
That, perhaps, is the only evolution available to us now.