What Is the Ganzfeld Experiment?

Medically Reviewed by Dan Brennan, MD on June 02, 2021
3 min read

‌The ganzfeld effect happens when you undergo sensory deprivation for some time and your brain tries to make sense of what is happening. Everyday life is full of sights and sounds. So, without sensory stimulation, your brain will fill in the gaps, which often causes visual hallucinations and auditory hallucinations. ‌

The ganzfeld effect may cause an altered state of consciousness or extrasensory perception — also called the sixth sense or psi. While scientists are still debating these possible results, you can experience the above hallucinations by doing a ganzfeld experiment at home.

‌The word “ganzfeld” in German translates to “whole field,” which describes the purpose of the experiment. To experience the ganzfeld effect, your whole field of vision must be filled with a uniform color, with no changes in brightness, no moving objects, no color variation, or no changes in depth detection ability. 

After your vision is completely filled by this wall of color, it only takes a couple of minutes for your brain to start changing your perception. You may feel a slow drop in brightness even though you know the light in the room isn’t changing. Shortly after, you may see different colors, eye tracers, blood vessels, or fading colors. ‌

If you stay in this state for much longer, you may start seeing vivid hallucinations — similar to those created by some drugs. Your brain has nothing to make sense of, so it starts boosting the small amount of information coming in.

‌The hardest part about performing the ganzfeld experiment is getting the visual conditions right. This is achieved by cutting a ping pong ball in half and placing each half over your eyes. The balls have to be spotless and shouldn't let any light in through the corners. A tape is placed around the edges of the balls to account for this and to ensure that the balls don't fall off during the experiment.

Another widely used method includes making a face mask out of paper and taping the edges. The paper mask lets in just the right amount of light and provides a uniform viewing area. 

The room should be filled with a specific color of light, preferably red light. The light shouldn't flicker, and nothing in the room should be able to induce visual disturbance. To get the full effect there shouldn't be any auditory disturbances in the room. You'll also be instructed to listen to white noise throughout the experiment.

‌The ganzfeld experiment is usually a safe way to feel the subconscious without any lasting effects. But, this experience can be unsettling depending on how long you are in it and on which hallucinations you see. You may feel disoriented for a while after finishing the experiment and might not be able to make sense of what you just saw. If you have a mental health condition like schizophrenia, engaging in this experiment could be a very negative experience. 

For years, parapsychologists and other academics have used the ganzfeld experiment to try and find evidence for the sixth sense. This is the ability of your brain to know future events or predict things without any sensory input. Although often considered pseudoscience, parapsychology is the study of psychic abilities, precognition, and telepathy. The ganzfeld experiment was thought to be the link between this field and the scientific community. 

Researchers have tried to test this link by placing a person — called the receiver — in a room in the same conditions described above. Another person — called the sender — is placed in a separate room and is told to focus on a single target — usually a photograph. At the same time, the receiver describes their hallucinatory experience in as much detail as possible. 

If the receiver’s experience matches the sender’s target, the test is considered a success. But, the results from this test have never fully proven a connection between the minds of two different people. This is partly due to inconsistencies across a large number of studies and a variety of mistakes within the experiment itself. 

In general, the ganzfeld experiment can put a person into a different state of consciousness — somewhere in between being asleep and awake. While in this state, there is a noticeable change in awareness and you may tend to feel like time has passed more quickly.