1 Definition
An illusion or illusionary misjudgement is a psychiatric and psychological term for a misperception that is based on a wrong interpretation of actual sensory impressions. In other words: An existent thing is perceived - but not the way it actually is.
2 Background
Contrary to a hallucination, an illusion is based on an existing stimulus. An example could be an anxious person who is walking through darkness and perceiving another human in a tree. Tiredness or states of intoxication can also cause this phenomenon.
