Seeing red where it isn't: how a stunning optical illusion tricks the brain (video).

There are numerous optical illusions in the world: from a cigar embedded in brickwork to the "dress" that went viral online, in recent years, an increasing number of optical illusions have captured people's attention. Now, a scientist has explained yet another optical illusion that makes us perceive strawberries as red, even though that's not the case, according to Daily Mail.

Biologist and BBC presenter, Dr. Dean Jackson, shared a peculiar illusion on his TikTok channel that deceives the human brain into thinking that strawberries are red. The video starts with Dr. Jackson displaying an image of a red strawberry on a white plate.

He then adds a blue filter to the video and asks again what color the strawberry is. Initially, it seems that the berries are red, but according to Dr. Jackson, this is not true — at this stage, the strawberry in the photo is actually gray.

Interestingly, at this moment, there is simply no red color in the photo, as it does not pass through the blue filter. This strange optical illusion arises because our brain is confused by what our eyes see.

The researcher notes that the back of the human eye contains two types of photoreceptors that allow us to respond to light. While "rods" are sensitive to motion, "cones" are sensitive to light, and each responds to its own color.

In the video shown by Dr. Jackson, the blue filter only allows blue light to pass through — meaning everything else should appear gray. However, when our brain recognizes that strawberries are typically red, it can interpret the gray light to make it seem that way. Simply put, we have a singular experience of perceiving strawberries as red, so the brain fills in the details for us.

Still, in the picture shown by Dr. Jackson, the strawberry is indeed gray, regardless of the mind games our brain plays.

To prove this, Dr. Jackson continues to mask the strawberry by adding stripes around it. This helps to illustrate that with the addition of the blue filter, the strawberry has turned gray.

Dr. Jackson's video has been viewed over 3.4 million times on TikTok, and several puzzled viewers took to the comments to discuss the illusion. Some users noted that this illusion has driven them crazy for several years, while most still consider it one of the best.