This is the eerily fun illusion of having the seemingly inanimate facial features on a statue or bust follow your movements across the room; up and down, side-to-side, or pretty much everywhere.
One common term for this is the Hollow Face Effect, and even though its most famous usage can be seen by millions of Disney Park visitors each year from the hallway busts in the Haunted Mansion, this effect has been used for several years in cathedrals, galleries, and science centers.
One reason it is so fascinating is it is an extremely easy concept, and it’s all about perspective.
Here’s how it works. The moving face in the hollow face effect is merely a concave sculpture, like a mold or bowl. When looked at in the right lighting, and at the right angles, it appears to be a normal, convex bust or statue. Your brain wants to see a regular statue, so it tricks your mind into thinking it is.
This is coupled with another slightly more difficult concept, called pareidolia, which is, in simple terms, the mind’s ability to see faces in patterns. A face, of course, is normally convex. For example, the tip of the nose is closer to the viewer than it’s ears and cheekbones.
When you look at a hollow face sculpture, the outer edges of the mold become hidden as you move your own head, causing your mind and eye to think the head is turning towards you, rather than being slightly covered up. A simple diagram and more detailed explanation of how the effect works can be found on BrainFacts.org.
Now, here’s the best part; you can make your own moving sculpture in a matter of minutes. Thanks to a recent viral video of a T-Rex illusion that has gathered more than 3.5 million views, people have rediscovered something called the “Gathering for Gardner” dragon, created for an event celebrating the late scientist and mathematician Martin Gardner. The pattern for this dragon can be found on several educational and science sites, such as Grand Illusion.
It’s easy, all ages can participate, and it can be a quick after-school or lunchtime project. Plus, who doesn’t want their own very, very attentive pet dragon.