Could our ancestors see blue?

But it's not just about lighting conditions or optical illusions - evidence is mounting that until we have a way to describe something, we may not see its there.

Ancient languages, for instance, didn't have a word for blue and scientists believe as a result our ancestors didn't notice the colour even existed.

According to Business Insider's Kevin Loria, in 'The Odyssey,' Greek poet Homer famously describes the 'wine-dark sea.'

In 1858 William Gladstone, who later became the British prime minister, counted the colour references in the Homer's Odyssey and found blue wasn't mentioned at all.

Black is mentioned nearly 200 times and white about 100. Red, meanwhile, is mentioned fewer than 15 times, and yellow and green fewer than 10.

It wasn't just the Greeks. Blue also doesn't appear in the Koran, ancient Chinese stories, and an ancient Hebrew version of the Bible, according to a German philologist named Lazarus Geiger.

Egyptians, who were the only culture that could produce blue dyes, were the first ancient civilisation to have a word for the colour blue.

Once this product spread, other civilisations picked up on the colour, which doesn't readily appear in nature.   

Today, there remain tribes who don't have a colour for blue, such as the Himba people in Namibia. 

Several years ago, researchers showed some of the Himba tribe a circle with 11 green squares and one blue.

The study found they could not pick out which one was different from the others, or took much longer to make sense of it. 

However, the same tribe has many different words for green. When they were shown squares with one green a different shade, they could pick it out immediately.  

Another study focused on how Russian speakers have separate words for light blue (goluboy) and dark blue (siniy).

(dailymail.co.uk)