TORONTO - We all have our colour preferences, but two Canadian researchers argue all colours are not of the same value.

The colour blue inspires creativity while the colour red improves attention to detail, they report in a study published online Thursday by the journal Science.

Ravi Mehta and Rui Zhu of the University of British Columbia say their conclusions could have a wide range of implications for daily life, from the use of colour in educational settings to its use on street signs or warning labels.

The scientists undertook the 18-month study to resolve conflicting theories on the effects of red and blue on people's performance, Zhu told The Canadian Press in a telephone interview.

"Some people had found that red colour will enhance performance (more) than blue and others had found exactly the opposite."

Mehta and Zhu tested people with a variety of mental tasks performed on computers, including solving anagrams and memorizing lists of words. The tasks took place in front of either a blue, red, or neutral background.

"The things that come to people's mind when they think about red colour is stop sign, red light, blood, ambulance and emergency," Zhu said.

Those images trigger an avoidance motivation and when people are in what Zhu called an "avoidance mindset," they're likely to be vigilant and careful.

But the researchers found blue to be entirely different.

Zhu said the most salient association people link to blue is ocean and sky. That means open, free and peaceful, and if the environment is safe people are more likely to use exploratory strategies in their decision making, she said.

The researchers said different colours may be used to enhance cognitive performance in a number of ways.