Pirouette Silhouette

Stare at the animated dancer. Within a few moments most will see her moving clockwise, then counterclockwise, and back and forth. If you are having trouble seeing her spin in the opposite direction, concentrate on a different part of her body, or trace her projected foot with your finger and tell yourself she is moving in the opposite direction. The power of suggestion works wonders—as does the power of assumption, which is so strangely (and fascinatingly) demonstrated here.

How It Works

In this optical high created by Japanese designer Nobuyuki Kayahara, some people see the spinning dancer on her right leg spinning to the left; others see her on her left leg spinning to the right. If gazed at long enough, most will see her change direction, spin left for few moments, then right, and back.

The dancer is able to switch directions in our brains because she has no depth cues. The details defining the swinging direction of her arms, legs, and torso are too ambiguous for our visual system to understand. The brain, having such little information, starts making assumptions. It takes the information with which it is immediately presented and assumes a certain direction. However, if we concentrate on other details of the dancer that counter this assumed direction, the brain corrects the previous assumption and spins her in the opposite direction. Some people see her changing directions every few moments; for others it takes minutes. Some claim to never see it.

An interesting side note: People with bipolar disorder will be slower to see the dancer change direction as their reversal rates in perception are generally more tightly fixed.