Three tricky optical illusions show how images can deceive the eye

Optical illusions can be hotly debated - who could forget the infamous white and gold/blue and black dress in 2015? Now a new set of images are showing again how colours and shapes can trick the eyes.

To support the launch of its new TV ad, highlighting how we all put our own unique spin on everyday things, Gala Spins has produced a series of optical illusions, designed to challenge Brits on how they see things.

These were then put to the test, with Brits polled on what they could see depending on their unique vision. Gala Spins also partnered with Bhavin Shah, Behavioural Optometrist at Central Vision Opticians, to explain how and why we see different images and colours.

What shape do you see?

More than seven in ten (71%) see a yellow butterfly in this image, while 29% see two faces looking at each other.

On the findings, Bhavin comments: “Many people will see the butterfly first, before zeroing in on the detail of the faces. Humans have a propensity to human faces and are always drawn to them. There are parts of the brain that respond specifically to faces so once we’ve seen it in the illusion, we’ll tend to see that more.”

Which spots move the most?

When looking at these images, different coloured spots appear to move more than others, and for some, the spots don’t move at all.

Nearly three quarters of people (71%) shown these images said that the orange spots on a purple background are moving for them. Meanwhile, over half (57%) said that the blue spots on a green background appeared to be moving.

On the other hand, only three in ten (29%) of people said that the purple spots on a blue background seemed to be in motion.

Bhavin says: “The rotating motion is caused by signal processing of the complex image, especially in parts of the retina that are just outside the central part of the vision, as well as very tiny movements of the eyes. The brain assumes that the eyes are stable and not-moving, therefore it has to assume that the pattern must be moving instead, so the pattern starts to move. Some people have more of these tiny eye movements than others and some are more sensitive to contrast in the pattern, so there will be some variation in the appearance of movement.”

What colour is the handbag?

Nearly two thirds (63%) of people see a green handbag, while 37% of participants see it as blue.

Bhavin comments: “In this case, there isn’t enough information or context about the object available, so the brain has to apply its own processing and create a reality that it feels is correct. Some people will process the colour as if its indoor lighting and others as if it’s outdoor, which is why people see different colours.”

Bhavin adds: “Most optical illusions work because our eyes take in optical information from the light and our brains have evolved to create a reality based on that information. However, there are lots of potential sources of error that can result in the brain interpreting something differently.

“The brain has lots of ways that it fills in missing information based on experience, learned visual responses and understanding of the world and context. Optical illusions occur when there isn’t enough information or context about the object, so our brain has to fill in the gaps, meaning different people see different things.”