Have you ever noticed your body reacting to a situation before your brain has even had a chance to process what is happening? Imagine you are in a new, healthy relationship. Your mind knows this person is kind and reliable. However, the moment they are five minutes late for a text, your heart starts racing and your stomach knots up. Your cognitive mind is saying, “They’re just busy,” but your body is responding to an old pattern from a previous, volatile experience.
In the late 1980s, psychologist Pierre Perruchet identified a startling mismatch between our conscious expectations and our physical conditioning. In his experiments, participants were exposed to a tone followed by a puff of air to the eye. As the tone-puff pairings repeated, the participants’ eyeblink reflex grew stronger and more consistent. However, when asked, their conscious expectation of the puff was actually decreasing. We all have this thought sometimes: “It has happened so many times, surely it won’t happen again.” Yet, their body “learned” the pattern independently, outperforming the mind’s logic.
This is the Perruchet Effect. The disconnection between the mind’s expectations and the body’s picked-up patterns. Even when people expect an outcome, their conditioned response can still grow stronger. It suggests that we have two distinct learning systems. The cognitive system updates with new information and logic, and the automatic system reinforces patterns through sheer repetition.
And that is why “knowing” better doesn’t always lead to “doing” better. While your mind might be convinced that you are safe, your automatic system may still be reinforcing an old survival pattern simply because that pattern has shown so many times in the past.
*What is Daily Insight? An ongoing series of quick, bite-sized brain snacks. Every week, there are three research-based facts and three research-informed reflective notes.
