Definition
An illusion is a false interpretation or misperception of a real external stimulus.
Examples
- Rope mistaken for a snake
- Coat hanging on a wall mistaken for a person
- Rustling leaves interpreted as human footsteps
Causes
- Fear
- Fatigue
- Poor illumination
- Anxiety
- Mental illness
Delusion vs Hallucination vs Illusion
| Feature | Delusion | Hallucination | Illusion |
|---|---|---|---|
| Nature | Disorder of thought | Disorder of perception | Misinterpretation of perception |
| External stimulus | Not related to stimulus | Absent | Present |
| Basis | False belief | False sensory perception | Wrong interpretation of a real stimulus |
| Example | "People are trying to kill me." | Hearing voices when nobody is speaking | Rope mistaken for snake |
| Sensory involvement | No | Yes | Yes |