Related topics: brain

Why people tend to believe UFOs are extraterrestrial

Most of us still call them UFOs—unidentified flying objects. NASA recently adopted the term "unidentified anomalous phenomena," or UAP. Either way, every few years popular claims resurface that these things are not of our ...

Curious comet's rare close approach

Comet C/2022 E3 (ZTF) today makes its closest approach to Earth before likely leaving our solar system forever. At billions of years old and not seen since Neanderthals roamed, the green comet continues to intrigue as it ...

Moral illusions may alter our behavior

Just as optical illusions can fool the eye to present a distorted image of reality, moral illusions can fool our decision-making ability, making us more selfish. This is the conclusion of a newly presented doctoral thesis ...

New, highly tunable composite materials—with a twist

Watch for the patterns created as the circles move across each other. Those patterns, created by two sets of lines offset from each other, are called moiré (pronounced mwar-AY) effects. As optical illusions, moiré patterns ...

A solar illusion: Coronal loops may not be what they seem

Many coronal loops—ropey strands of plasma that scientists have long thought existed in the Sun's atmosphere—may actually be optical illusions, according to a new paper that challenges prevailing assumptions of what we ...

Guppies found to be susceptible to optical illusions

A team of researchers working at the University of Padova, in Italy, has found that like humans and many other animals, guppies are susceptible to optical illusions. In their paper published in the journal Biology Letters, ...

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Illusion

An illusion is a distortion of the senses, revealing how the brain normally organizes and interprets sensory stimulation. While illusions distort reality, they are generally shared by most people. Illusions may occur with more of the human senses than vision, but visual illusions, optical illusions, are the most well known and understood. The emphasis on visual illusions occurs because vision often dominates the other senses. For example, individuals watching a ventriloquist will perceive the voice is coming from the dummy since they are able to see the dummy mouth the words. Some illusions are based on general assumptions the brain makes during perception. These assumptions are made using organizational principles, like Gestalt, an individual's ability of depth perception and motion perception, and perceptual constancy. Other illusions occur because of biological sensory structures within the human body or conditions outside of the body within one’s physical environment.

The term illusion refers to a specific form of sensory distortion. Unlike a hallucination, which is a distortion in the absence of a stimulus, an illusion describes a misinterpretation of a true sensation. For example, hearing voices regardless of the environment would be a hallucination, whereas hearing voices in the sound of running water (or other auditory source) would be an illusion.

Mimes are known for a repertoire of illusions that are created by physical means. The mime artist creates an illusion of acting upon or being acted upon by an unseen object. These illusions exploit the audience's assumptions about the physical world. Well known examples include "walls", "climbing stairs", "leaning", "descending ladders", "pulling and pushing" etc.

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