Psychological Effects of Strobes

Perception of Time

• The phenomenon of the stroboscopic effect occurs when a moving object isn't perceived continuously and is incorrectly perceived to be going slower, to have stopped completely or to be going backward. A flashing strobe light reduces the number of images that a person sees in a given period of time. It can therefore create optical illusions, such as making movement look jerky or slower. The effect of a strobe light in a very dark situation can be disorienting.

Disorientation

• Another possible consequence of the stroboscopic effect has been utilized in war. Strobe lights can make people become dizzy and nauseated and to lose balance. Today the U.S. Army uses these "light-based personnel immobilization devices" to disable and disorient enemies. A more primitive version of this device was used in World War II.

Capturing Attention

• A study done by the Virginia Polytechnic Institute and State University showed that younger test subjects showed faster reaction times when exposed to a strobe light. This effect wasn't observed in older test subjects. This study suggested that the strobe light could be applied effectively as an alert in emergency systems.

Seizures and Headaches

• For people with photosensitive epilepsy, strobe lights -- as well as other flashing lights or rapidly moving patterns -- can trigger seizures. Usually, lights that flash around five to 30 times per second are the most likely to be harmful to people with epilepsy. Strobe lights themselves cannot cause epilepsy in individuals who do not have it. However, many people find that strobe lights can cause severe headaches and migraines.