Psychologist Baffles TikTok Viewers With 'Trippy' Optical Illusion

A psychologist has posted an image on TikTok that has left viewers baffled. Dr. Julie Smith shared the illusion with her 2.8 million followers in a video that has been viewed more than 400,000 times.

In the video, Smith explains to her viewers that they're "about to experience a negative afterimage," telling them, "I'm going to trick your brain into seeing color where there is none."

At this point, Smith is in black and white and has a white cross on her forehead, but she tells her viewers that when they watch it back, the video will be in "full color."

The video becomes contrasted, and Dr. Smith tells her audience to "keep focusing on the cross on my head," explaining that: "By focusing on the cross your brain is going to do something incredible. Overexposing the receptors in your eyes to certain colors causes the brain to see inverted colors when the black and white image appears.

She instructs her viewers to keep focusing on the cross when the video reverts to black and white. When the video played on a loop for the second time, as Dr. Smith predicted, the video appeared to be in color.

In the caption of the video, Smith asks her viewers, "Did you see color? How long for and what stood out most?" and told them to "Try it with the brightness turned up for max effect!"

TikTok viewers were understandably taken aback by the optical illusion as they shared their experiences in the comments.

@drjuliesmith

🤔 Did you see colour? How long for & what stood out most? Try it with the brightness turned up for max effect! ##learnontiktok ##illusion ##psychology

♬ Say So (Instrumental Version) [Originally Performed by Doja Cat] - Elliot Van Coup

One user said: "That was very trippy... My brain didn't want to believe it, even when I saw it happen," while another said: "That freaked me you so bad! As long as I kept focusing on the X I saw color for almost the entire black and white part."

So how is this optical illusion possible?

"Negative afterimages occur when the rods and cones, which are part of the retina, are overstimulated and become desensitized," according to the Charlotte Eye, Ear, Nose, and Throat Associates.

"This desensitization is strongest for cells viewing the brightest part of the image but is weakest for those viewing the darkest. When you look away, the least depleted cells react strongest, and vice versa, and you see an image with colors that are the reverse of how the image originally appeared. Many optical illusions take advantage of negative afterimages."

Newsweek has contacted Smith for comment.

Close-up of an eye
Stock image of an eye. A psychologist has baffled her TikTok followers with a "trippy" optical illusion. monkeybusinessimages/Getty