Aphantasia Glossary

Aphantasia is the inability to voluntarily create mental images. People with aphantasia cannot visualize faces, places, or objects in their mind's eye, although they can recognize and describe them. The term was coined by neurologist Adam Zeman in 2015.

Hyperphantasia refers to the ability to form extremely vivid, photorealistic mental images. People with hyperphantasia can imagine scenes so detailed that their inner images can almost be confused with real perception.

Prophantasia refers to the projection of mental images into real visual space. People with prophantasia see their imaginations as if superimposed on their environment.

Multisensory aphantasia refers to the absence of imagery in multiple or all sensory modalities, not just the visual domain. Affected individuals also cannot imagine sounds, smells, or touch sensations.

The visual cortex is the region of the cerebral cortex that processes visual information. Located in the back of the head (occipital lobe), it is responsible for both seeing and visual imagination.

The prefrontal cortex is the foremost part of the frontal lobe and controls executive functions such as planning, decision-making, and impulse control. It also initiates and controls mental images.

The Default Mode Network (DMN) is a network of brain regions active during daydreaming, self-reflection, and mental time travel. It shows altered patterns in people with aphantasia.

Synesthesia is a neurological phenomenon where stimulation of one sense automatically triggers experiences in another sense. For example, letters may be perceived as colors.

Mental images are internal visual representations that arise without external stimuli. They enable seeing objects, scenes, or people before the "mind's eye," such as when remembering, dreaming, or planning.

The 'mind's eye' is the metaphorical term for the ability to create and view mental images. It describes the subjective experience of visual imagination.

SDAM is a memory condition where episodic autobiographical memories are severely limited. Affected individuals cannot mentally return to past experiences, although factual knowledge is preserved.

Eidetic memory refers to the ability to retain images or scenes with photographic accuracy after brief viewing. It is the opposite of aphantasia.

Image Streaming is a visualization technique where spontaneously arising inner images are described aloud. It is discussed as a possible training for people with aphantasia.

Episodic memory stores autobiographical memories of personal experiences with spatial, temporal, and emotional context. It enables "mental time travel" into one's own past.

Prosopagnosia is the inability to recognize or distinguish faces. It occurs more frequently in people with aphantasia and can be congenital or acquired through brain damage.

The VVIQ is a standardized questionnaire for measuring the vividness of visual imagery. It consists of 16 items where participants rate their ability to visualize on a 5-point scale.

Binocular Rivalry is a visual phenomenon and test procedure where a different image is shown to each eye. Perception alternates between both images, influenced by mental imagination.

The PSIQ is a questionnaire that measures imagery ability across all five sensory modalities: visual, auditory, olfactory, gustatory, and tactile. It is more comprehensive than the purely visual VVIQ.

Adam Zeman is a British neurologist and professor at the University of Exeter who coined the term "aphantasia" in 2015 and significantly advances scientific research on this phenomenon.