“Just think positive!” – ever heard that? Sounds simple, but somehow it doesn’t work. Why? Because our brain doesn’t operate by Instagram mantras; it operates by laws shaped by millions of years of evolution. It’s like an ancient guard dog, primed to sniff out danger. It’s wired to scan the horizon for sabre-toothed tigers, rival tribes, or a mammoth that might trample you. And if there’s no tiger, but there’s a utility bill or future uncertainty, it will perceive it as a threat.

Imagine you’re in the savanna. Your life depends on how quickly you spot danger. It’s advantageous for the brain to be paranoid, to have a negative bias. It’s better to make ten false alarms and run from a harmless bush than to make one mistake and miss a predator. This bias towards negative information is called the negativity bias — an evolutionary mechanism that helped our ancestors survive.

It’s the 21st century; there are no tigers. Yet, our brain, this unique machine, evolved over thousands of years, while civilization is just a few hundred. So, it continues to operate on old algorithms. It scans news, social media, your internal dialogue — looking for threats everywhere. And it finds them! Negative thoughts about work, the future, your health — these are all the same “sabre-toothed tigers,” just in modern packaging. The brain doesn’t distinguish between a real threat and a threat you conjured in your head. For it, whether it’s a bear in the forest or an unpaid bill, it’s a reason to activate the “fight or flight” system.

The cost of such “protection” is high. Constant activation of the stress response depletes the body. It’s like keeping your foot on the accelerator even when stuck in traffic. Fuel is consumed, the engine wears out, but there’s no movement. Cortisol (the stress hormone) and adrenaline, produced in response to these negative thoughts, find no outlet because there’s no real “flight” or “fight.” Instead, they attack your cardiovascular system, immune system, digestion — your entire body. You feel drained, even though you haven’t done anything physically.

Have you ever wondered why, if you start thinking about something bad, that “bad” doesn’t just disappear but sprouts new details, scenarios, and fears? This is not a coincidence. This is another trap our brain falls into, or as we call it, an amplification loop.

Imagine your brain has two metaphorical “departments”: the prefrontal cortex, responsible for rational thought and planning, and the limbic system (where the amygdala is located), responsible for emotions and instincts. Ideally, they work in balance. But when you constantly “feed” yourself negative thoughts, the limbic system takes “command.”

Each negative thought, like a drop of water, lands on the scales of the limbic system. The more such drops, the more intensely the system activates, and the more stress hormones are produced. These hormones not only cause physical tension but also affect the function of the prefrontal cortex, reducing its ability for rational analysis and emotional control. This is called stress-induced cognitive impairment. Under stress, the brain starts to function less effectively, and this is not because you “gave up”, but because it’s biochemically logical.

It’s like a horse being spurred: the more you prod it, the more it panics and the less it thinks clearly. As a result, you get caught in a real cycle: negative thought → limbic system activation → stress hormone release → impaired prefrontal cortex function → even more negative thoughts.

The effect of accumulating negative experiences, or “learned helplessness” (though “conditioned helplessness” is more accurate, as shown by Martin Seligman in his 1960s experiments), also plays a role. If you’ve had an experience where negative thoughts led to unpleasant consequences (for example, you over-stressed before an exam and everything went awry), your brain remembers this connection. Next time, facing a similar situation, it starts generating negative thoughts, predicting failure and activating the stress response even before anything has happened. This is not because you are “weak“, but because your brain is very good at learning — including how to harm itself.

The brain, in essence, becomes a hostage to its own attempts to protect you. It has become so engrossed in searching for threats that it starts generating them itself, even where none exist. And in this loop, negative thoughts don’t just pass by; they linger, take root, and begin to control your state.