In psychology, the Stroop effect is the delay in reaction time between congruent and incongruent stimuli.

I had a practice session today for Sunday's praise and worship, and in one of the songs, the lead singer requested a key change.

Key changes mess up my flow, because I memorize a certain routine to minimize mistakes while playing.

It was just a simple one-step key change, from C to B-flat, so I could still manage.

I was looking at every chord in the old key on my printed sheet music, and then translating it to the new key in real time.

But at one point, my visual stimuli of seeing the C chord won over my brain's background process that was telling my hands to play B-flat, causing me to hit the wrong chords.

I thought about why that happens and it turns out I was experiencing the Stroop effect.

You've probably experienced this effect yourself in a certain brain teaser.

Known as the Stroop test, you're given a list of words that are printed in a different color than the meaning of the word. And your task is to name the color of the word, not the word itself, as fast as you can.

For example, when presented with the word "Red", it's easier to say red, as opposed to the color of the text (blue).

There are some theories used to explain why this effect happens.

They're all based on the idea that our brains processes relevant and irrelevant information in parallel, but they both "race" to your brain's central processor to be chosen as a response.

This neurophysiological test has different variations, and can reveal a lot about your brain and how it processes information.

Among the most important uses is in measuring a person's selective attention capacity and skills, as well as their processing speed ability.

It can also diagnose different psychiatric and neurological disorders such as ADHD, schizophrenia, and depression.

What I find most interesting is that studying this effect might help us better understand the black box that is our brain, which can allow us to overcome our fast instinctual thinking, known as System 1 in the book Thinking, Fast and Slow, helping us reach to more logical conclusions.