THIS optical illusion will leave you scratching your head.
Despite one pear looking darker than the other underneath the black and white lines, they're both actually the same colour.
This mechanism is an example of a brightness illusion.
Similar visual puzzles have been around for over 100 years and follow a familiar pattern.
Typically, two identical objects are placed on a striped or graded background.
The objects appear very different based on where they are placed against the background.
In June 2020, researchers at the Massachusetts Institute of Technology investigated the mechanism behind the illusions.
They showed that the phenomenon relies on a quirk in the way that our brains process what we see.
When we look at an image, we estimate the brightness of an object before visual information reaches the brain's visual cortex.
It means that objects of the same colour can appear brighter or darker than they are based on the background they're presented on.
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"All of our experiments point to the conclusion that this is a low-level phenomenon," MIT's Professor Pawan Sinha said at the time.
"The results help answer the question of what is the mechanism that underlies this very fundamental process of brightness estimation, which is a building block of many other kinds of visual analyses."
Optical illusions are often just a bit of fun, but they also hold real value for scientists.
The brain puzzles help researchers shed light on the inner workings of the mind and how it reacts to its surroundings.
Dr Gustav Kuhn, a psychologist and human perception expert at Goldsmiths University in London, told the Sun earlier this month that illusions are important to our understanding of the brain.
"We typically take perception for granted, and rarely think about the hard work that underpins everyday tasks, such as seeing a cup of coffee in front of you," he said.
"Visual illusions highlight errors in perception, and they provide important glimpses into the hidden neural processes that allow us to see the world around us."
It follows the release of a spooky illusion earlier this month that makes the viewer feel as though they are tumbling into a black hole.
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