Glossary

Hallucination

A hallucination is a sensory perception that occurs without an external stimulus.

Overview

Hallucinations can involve sight, sound, or other senses. They may occur in neurological, psychiatric, or normal conditions such as sleep transitions.

Key Insight

Hallucinations show that the brain can generate vivid perceptual experience in the absence of external input.

Scientific Status

Well documented in neuroscience and psychiatry.

How Researchers Study It

Researchers study hallucinations through neuroimaging, clinical assessment, and sleep studies.

Quick Facts

Field
neuroscience, psychiatry
Related Concepts
perception, sleep paralysis
Typical Context
clinical and sleep research

FAQ

  • Are hallucinations always a sign of illness?

    No. Isolated hallucinations can occur in healthy people, for example during sleep paralysis or hypnagogia.