We know colour can change how we feel. But can it change what's happening inside our brains? Scientists have been trying to answer that question for decades, using EEG, a test that measures the brain's electrical activity through sensors on the scalp.

A quick guide to brain waves

Your brain is always producing electrical rhythms. One of the most studied is the alpha wave, which tends to show up when you're awake but relaxed, like when you're calm, reflective or letting your mind wander. Higher-frequency beta waves tend to rise when you're alert, busy or under pressure.

Because alpha waves are linked to that calm, open state of mind, researchers have long been curious about whether colour can affect them.

Blue and green linked to calmer brain activity

In a 2009 study published in a Korean journal of aesthetics and cosmetology, researchers measured brain waves before and after exposing people to red, green and blue light. Red tended to raise high beta activity, which the researchers linked to strain and stress. Green and blue tended to increase alpha activity, which they linked to relaxation and stress relief. It was a small study, and it used coloured light rather than paper, but the pattern fits what many people feel about blue.

A twist: blue paper and attention

A 2007 study from Japan, published in the Journal of Physiological Anthropology, looked at something closer to a notebook. Participants looked at sheets of red, green and blue paper while their brain activity was recorded. People described red as feeling more exciting and warm. But by one EEG measure, blue paper was linked to a stronger state of alertness than the researchers expected.

In other words, blue may not simply relax the brain. It may help it stay calm and engaged at the same time.

Calm and alert: the ideal state for ideas

That combination matters. Creative thinking tends to happen when you feel safe enough to explore but awake enough to catch good ideas when they appear. It's the same "approach" mindset that researchers at the University of British Columbia linked to blue in their 2009 study in Science.

What we can and can't say

The brain science of colour is still young. Studies are often small, they use different methods, and their results don't always agree. So we won't tell you blue rewires your brain. What the research does suggest is that colour isn't neutral. It's linked to how we feel and think, often without us noticing.

That's why we chose blue for every Notedfy page. It's a small change to your environment, built on real research, designed to help you settle in and think.