Mosaic world image

Illusions of light title

Much of our research is focused on understanding how and why we see illusions, since to understand how we see correctly, we need to understand why it seems that we sometimes see incorrectly. Illusions, therefore, are critical windows into the mind.

The beautiful thing about illusions is that they make us realise not only that things are never what they seem, but also that our experiences of the world shape our understanding of it.

The whole concept of an illusion is predicated on a misconception. When you see an illusion, you are entertaining two realities simultaneously. Take the first illusion on this page, for example: you see one reality (two grey squares that look different) but you also know another reality, namely that the grey squares are, in fact, physically the same. In other words, the brain causes the illusion by in that moment trying to make sense of what the eyes are seeing. You’re in the position of actually experiencing yourself having an experience.

Illusions are useful as a research tool because they tell us how the brain works, that the brain evolved NOT to see the retinal image (which is made up of meaningless, or ambiguous, patterns of light) – i.e. not the world ‘as it is’ – but to see the world in a way that proved useful in the past. It constructs what it knows by searching for useful patterns in sensory information and then associating those patterns with a past record of their behavioural relevance, and then using that information to guide behaviour. Which means that the brain is innately a creative and curious machine that evolved to continually redefine normality, a ‘normality’ that is necessarily contextual and historical.

The powerful colour, motion and shape illusions on this page have all been created in-house. Feel free to use these images, with proper accreditation.

Download our powerpoint presenter for all illusions here