Blue objects feel warmer to the touch than red ones of the same temperature, a new study has found.
Researchers at the Nippon Telegraph and Telephone Corporation in Japan led participants into a pitch-dark room with a temperature-controlled plate lit up in either blue or red.
The participants placed their hands on the surface and were asked to state whether it felt warm.
The study found that red-coloured surfaces needed to be about 0.5 degrees Celsius hotter than blue ones before they felt at all warm to the touch, 'Scientific American' reported.
"I was very surprised. I think as most people, our expectation is that red objects should feel warm and blue objects should feel cold. We get a totally reversed result," said Hsin-Ni Ho, the study's lead author.
Researchers then hypothesised that when it comes to touch, what we feel might be strongly influenced by our expectations.
Since our minds anticipate a warm red object, it takes a higher temperature for us to believe that the object is unusually hot.
To confirm the idea, Ho's team conducted another experiment. Instead of colouring the heated surface, they projected red or blue light onto participant's hands.
This time, red hands made surfaces feel warm at lower temperatures than blue hands. The reason, said Ho, is that our brain expects a red hand to already be warm, so when we touch a slightly hot object we interpret it as being warmer than it is.
The study is published in the journal Scientific Reports.