Have you ever wondered if you see the same colours as other people? Most people know what blue is when they see it.  It's the colour of sea, sky and sapphires. They see the colour and call it 'blue' because they were taught the word and associated it with what they saw. But how do you know what you see as blue isn't someone else's red, and vice versa?

The ability to perceive different colours is down to receptors in our eyes known as cones. Light waves hit these receptors and they react depending on which colour the light is, sending signals to the brain. The brain then decodes these signals to determine which colour light the eyes are receiving.

Some people's receptors are more developed than others. People with weaker receptors usually have colour blindness. The inability of the receptor to interpret the light waves correctly means that some people cannot distinguish between different shades of a colour.

Those with more enhanced receptors can see more shades of one colour, which is the first way in which people may see colours differently from each other. We sometimes hear people having an argument about whether something is dark blue or black. It might be because one person has stronger receptors to interpret the light than another.

In the past, most scientists would argue that everyone saw colours in the same way. However, research was conducted on monkeys, in which they were injected with a virus affecting their receptors. This enabled them to distinguish more colours than usual and brought an intriguing revelation. Normally monkeys can only see in blue and green, but the virus allowed monkeys to see red.

The neurons in their brains spontaneously adapted to be able to understand new colours, which might mean the neurons in our brains are not hardwired to automatically understand which colour is which. This implies that our brains and neurons may adapt depending on our stimulus during the developmental phase. Colour could be a very personal experience, unique to everyone.

So, the next time you talk about your favourite colour, just remember if yours is blue and your friend says red, you might actually be thinking about the same colour. What if everyone in the world has the same favourite colour, but just calls it different names?