Why You Sometimes React Before You Think

by Erica Tuminski November 07, 2025

Why You Sometimes React Before You Think

By James Porter

Have you ever mistaken a coiled rope or object for a snake, or jumped at a loud backfire thinking it was a gunshot? These moments reveal something fascinating about how the brain processes information. Long before your logical mind has time to weigh in, another part of your brain—the amygdala—has already hit the panic button.

That’s because the amygdala, a small almond-shaped structure deep in the limbic system, gets information from your senses a split second before your prefrontal cortex (PFC), the brain’s “executive center.” Neuroscientist Joseph LeDoux describes this as the difference between the brain’s “low road” and “high road.” The low road is fast and dirty—it sends raw sensory information from the thalamus directly to the amygdala. The high road is slower and more refined—it routes that same information through the sensory cortex and PFC, where it can be analyzed, interpreted, and put into context.

This tiny delay—often just a few hundred milliseconds—is the reason we sometimes react before we think. It’s an evolutionary advantage that once saved our ancestors’ lives. Better to jump back from a stick that looks like a snake than to take extra time confirming what it is. The problem is that in our modern world, this same system often backfires. We experience false alarms: a slammed door sounds like danger, or a shadow in the dark triggers an unnecessary surge of adrenaline.

I recently had a vivid reminder of this built-in lag. I was replacing a printer cartridge and pulled out what I thought was a sealed magenta ink cartridge. Unbeknownst to me, the seal had broken and it was leaking. When I felt something wet on my fingers and looked down, my hand appeared to be dripping with bright red liquid—an uncanny imitation of blood. Even though I knew intellectually that I was handling an ink cartridge, for a split second my body reacted as if I were bleeding profusely. My heart rate jumped, my breath caught, and I instinctively pulled my hand back. Then, just as quickly, the PFC caught up, reinterpreting the scene correctly: not blood, just ink.

That split-second wave of alarm was my amygdala getting the news first. The rational explanation arrived a fraction of a second later. And that small gap between reaction and understanding is where much of our stress lives.

In stress management—and especially in mindfulness training—this neural delay is crucial to understand. The goal isn’t to eliminate the amygdala’s response; we need it for survival. Instead, we train the PFC to recognize false alarms quickly and restore balance. Mindfulness meditation, breathing exercises, and similar practices strengthen the pathways between the PFC and the amygdala so that the “thinking” brain can more effectively calm the “feeling” brain.

Think of it as building a faster recovery time. You’ll still jump when a car backfires or feel a jolt of fear when you hear a loud noise in the middle of night. But instead of staying trapped in that alarmed state, your PFC will step in more quickly to reinterpret the situation and shut down the unnecessary stress response.

Awareness is the first step. Simply knowing that your emotional brain gets information before your rational brain, can help you pause when you overreact. When you feel your pulse racing or your muscles tightening, that’s your amygdala talking. Take a breath, give your PFC a chance to catch up, and let reason take the wheel.

In the next installment, we’ll look at five practical strategies for training your brain to respond more calmly and recover more quickly from those automatic overreactions. Because while you can’t change the wiring that makes you react first, you can absolutely learn to manage what happens next.