Aphantasia
Aphantasia is the inability to form mental images; a person without a mind’s eye cannot imagine the scene of a sandy beach, for example. Approximately 1 to 4 percent of the population is estimated to experience this phenomenon.
People with aphantasia have a different way of perceiving and processing images and may not be able to visualize people, places, objects, or other images. Aphantasia was first documented in the late 1800s. It is not a clinical disorder or disability; instead, it is considered to be a neurological characteristic. People with aphantasia often do not even realize that they have it until their teenage or young adult years. A person living with aphantasia would be hard-pressed to consider what mental imagery means: You cannot see what you cannot see, so to speak.
People with aphantasia develop various alternative strategies to remember things, problem-solve, and think creatively. In 2015, research by Adam Zeman of the University of Exeter in the United Kingdom found that people without mental imagery compensate by relying on their verbal ability as well as conceptual thought.
Aphantasia as a Spectrum
Aphantasia exists on a spectrum: Some who live with it can visualize a mental image when they open their eyes; some have no mental imagery whatsoever; and others may be able to visualize an image that is dim, vague, or fuzzy. Some aphantasics see images in dreams while others don't. Some only have issues with visual imagery, while others have them in multiple sense modalities. Some have "flashbacks" or involuntary imagery; some can be induced to have visual imagery through psychedelics; and others are not susceptible to certain optical illusions.
Differences in brain structure may be involved, especially in brain regions used for mental visualization. In some individuals, the visual cortex may be less active or developed.
Aphantasia can run in families; a person with it is more likely than a person without it to have a family member with the characteristic. Genetics may influence certain brain regions that are involved in mental imagery.
Not being able to visualize a past event or something that happened may make it harder for a person to remember the event. They may remember certain aspects of what transpired, but not a mental image of it. Aphantasics may have poor episodic memory—the conscious memory of a previous experience.
People within the autism spectrum may experience aphantasia but while aphantasia and autism can co-occur, the former does not involve the challenges associated with the latter.
Developing aphantasia is relatively rare. However, damage to certain parts of the brain, such as the occipital lobe, may cause this phenomenon and so a stroke, concussion, or other brain injury could cause aphantasia.
Some people with aphantasia can have mental images during dreaming; however, they may not be as vivid or frequent as they are far others. Researchers are not sure why the ability to experience imagery during dreams is conserved in aphantasia, but it may involve the ability to visualize involuntarily, which occurs during dreaming, as opposed to consciously summoning mental imagery to mind.
Hyperaphantasia is the opposite of aphantasia; an individual with hyperaphantasia can vividly see mental imagery as if it were right before them. About 3 percent of people may have hyperaphantasia.
Health professionals may use imaging scans for testing which may include computed tomography, magnetic resonance imaging, or electroencephalograms. There are also surveys to gauge mental imagery, including the vividness of visual imagery questionnaire.
There is no reason to treat aphantasia; it is a cognitive variation in how one’s mental world is experienced. However, if aphantasia develops as the result of a health condition or brain injury, the underlying cause should be addressed.
