Neurodivergence & Imagery Related Terms

Acquired Aphantasia

The  inability to voluntarily generate mental images, resulting from brain injury, illness, or other neurological changes. Defined in 2015 by Adam Zeman. This condition can affect not only visual imagery but also any or all five sensory modalities. Individuals with acquired aphantasia typically rely on conceptual thinking rather than sensory-based mental representations.

Alexithymia

A personality trait characterised by difficulty identifying and describing one's feelings and emotions. Defined in 1972 by Sifneos & Nemiah. People with alexithymia may struggle with emotional awareness and introspection. Estimates suggest 10-15% of the population experiences some degree of alexithymia, with higher rates in neurodivergent individuals.

Anauralia

A proposed term for the absence or significant reduction of auditory imagery, defined in 2021 by Lambert & Perdy, similar to aphantasia but specific to the "mind’s ear." There are currently no prevalence statistics available. It is noted by some that lack inner sound that they possess inner speech. As this is a new term, its recognition and adoption may vary among researchers and practitioners.

Anendophasia

The absence of an inner speech or inner monologue, defined in 2023 by Nedergaard & Lupyan. Some individuals experience silent inner speech or experience thought as abstract concepts rather than in verbal form. Research suggests a wide variability in inner speech frequency across individuals, but exact statistics are unknown. As this is a new term, its recognition and adoption may vary among researchers and practitioners.

Aphantasia and Multisensory Aphantasia

The inability to voluntarily generate mental imagery, first recognised by Galton in the 1800's, it was formally recognised and defined in 2015 by Adam Zeman. Now understood as the opposite of hyperphantasia, revealing mental imagery occurs on a spectrum. The definition has changed since the discovery and is no longer limited to visual imagery alone, encompassing any of the five sensory modalities currently recognised; sight, sound, smell, taste and touch. It is referred to as multisensory aphantasia when more than one sensory modality is aphantasic. People with aphantasia typically rely on conceptual thinking in the abscense of sensory imagery.

Attention-Deficit/Hyperactivity Disorder (ADHD)

ADHD is a neurodevelopmental condition affecting attention, impulse control, and activity levels. First recognised by Crichton in 1702, and formally defined by the American Psychiatric Association (APA) in 1968.  It involves fast-paced thinking, intuitive insights and difficulty regulating focus, making individuals highly creative but prone to distraction and impulsivity.

Autism Spectrum Disorder (ASD)

A neurodevelopmental condition affecting communication, social interaction, and sensory processing, discovered by Bleuler in 1911, and popularised by Asperger in 1944. It involves deep focus, pattern recognition, and a unique way of perceiving the world, with the mind processing details and sensory input in a structured yet sometimes overwhelming manner—similar to how analytical thinking organises information into distinct categories.

Blindsight

Blindsight, defined by Weiskrantz in the 1970's, is a neurological condition in which a person with damage to the primary visual cortex can respond to visual stimuli without conscious awareness of seeing them. Despite being unable to perceive objects consciously, they can still detect motion, navigate obstacles, or guess visual properties at a higher-than-chance level, suggesting that some visual processing occurs outside of conscious awareness.

Cognition or Cognitive Thought

The mental process of acquiring knowledge and understanding through experience, sensory input, and thought. Cognition includes functions such as perception, memory, reasoning, problem-solving, learning, decision-making, and imagination—key components of intelligence and adaptive behaviour. Cognitive thought, as a specific aspect of cognition, involves the flow of ideas, reasoning, and mental activities, which can occur consciously or unconsciously.

Cognitive Intelligence or Intelligence

Cognitive intelligence is the ability to learn, reason, problem-solve, and adapt to new situations using memory, attention, and logical thinking. It enables individuals to process information, make decisions, and apply knowledge effectively in various contexts.

Congenital Aphantasia

The congenital inability to voluntarily generate mental imagery, present from birth. It was formally recognised and defined in 2015 by Adam Zeman. However, the definition has changed slightly since then, as more is understood by researchers. The term covers those that are born lacking imagery, excluding those with acquired or progressive aphantasia, which my result from injury, illness or disease. This is not limited to visual imagery and can encompass any or all five sensory modalities recognised. 

Consciousness

Consciousness is the state of being aware of and able to perceive one’s thoughts, emotions, and surroundings. It involves the ability to experience sensations, reflect on oneself, and respond to external stimuli. Consciousness can vary in depth and clarity, from full wakefulness to altered states like dreaming or meditation.

Conscious Perceptual Experiences or Thoughts

A deliberate and aware mental process involving perception, reasoning, decision-making, or mental imagery. It includes actively experiencing sensory input, generating mental images, and engaging in cognitive tasks with focused attention and awareness. This contrasts with unconscious or automatic processes, which occur without intentional effort.

Double Empathy Problem

The double empathy problem described by Dr Daimian Milton in 2012, describes the mutual misunderstandings between people with different neurocognitive perspectives, especially autistic and non-autistic individuals. It emphasises that communication difficulties are shared rather than one-sided, requiring awareness and effort from both parties.

Dyslexia

A specific learning difference that primarily affects reading, spelling, and writing skills, often linked to difficulties with phonological processing, working memory, and rapid naming. Dyslexia is not related to intelligence and can occur across a range of intellectual abilities. Individuals with dyslexia may also show strengths in problem-solving, creativity, and visual thinking. Recognised as a neurodivergent condition, dyslexia reflects a different cognitive profile rather than a deficit.

Emotional Blindness

Emotional blindness isn’t a clinical term but is sometimes used informally to describe an inability to recognise emotions in others, which is different from alexithymia—difficult recognising feelings and emotional in oneself. This trait is more directly associated with conditions like autism or certain neurological impairments. The MIR would differentiate them as potential types of introspective imagery and emotional imagery, respectively.

Emotional Intelligence

Emotional intelligence is the ability to recognise, understand, and manage one’s own emotions while also being able to perceive, interpret, and influence the emotions of others. It involves skills such as empathy, self-awareness, emotional regulation, and effective interpersonal communication, which contribute to personal and professional success.

False Awakening

A dream in which the sleeper believes they have woken up, often because the dream environment closely resembles reality and sensations feel extremely vivid. Defined in around 1960. This can create a loop where the person "wakes up" multiple times within the dream before actually regaining consciousness. False awakenings are commonly linked to lucid dreaming, sleep paralysis, and vivid dreaming states.

Eidedic Memory

An eidetic memory is the rare ability to vividly recall an image with high precision for a brief period after seeing it only once. The detailed image fades within a few minutes. It is most common in childhood, with studies suggesting that 2–10% of children between the ages of 6 and 12 may possess this ability. 

Empathy Deficit

Empathy deficit describes a reduced ability to recognise, understand, and share the emotions of others. While "empathy deficit disorder" (EDD) is not a formal medical diagnosis, the concept is used by mental health professionals to describe a pattern of behaviour that can affect social interactions. The trait is often associated with other conditions, including personality disorders, and overlaps significantly with alexithymia.

Extra Sensory Perception (ESP)

The ability to acquire information beyond the five known senses, often referred to as "sixth sense." ESP includes phenomena such as telepathy (mind-to-mind communication), clairvoyance (perceiving distant events), precognition (foreseeing the future), and psychometry (gaining information through touch). While widely debated, ESP remains a key topic in parapsychology and psychic research.

Global or Total Aphantasia and Dysikonesia

Global or Total aphantasia, formally termed Dysikonesia, (Monzel 2022), is a specific type of multisensory aphantasia that was defined by the Aphantasia Network in 2025, referring to the inability to generate mental imagery across all five recognised sensory modalities—visual, auditory, tactile, olfactory, and gustatory. Individuals with global aphantasia make up a small percent of those with aphantasia. 

Hallucination

An involuntary perception-like experience that occurs without an external stimulus, making it feel real despite having no basis in reality. Hallucinations can affect any sense, including visual, auditory, tactile, olfactory, and gustatory perceptions, and are often associated with conditions like schizophrenia, sleep disorders, or substance use.

Highly Sensitive Person (HSP)

A term describing individuals with heightened sensitivity to sensory stimuli, emotions, and social interactions. Defined in 1996 by Aron & Aron, HSPs process information and emotional imagery more deeply and are thought to make up 15-20% of the population.

Hyperempathy

The opposite of empathy deficit, hyperempathy describes an extremely intense, and often overwhelming, ability to perceive and absorb the emotional states of others. Though not a formal psychiatric diagnosis, the phenomenon is recognised by mental health professionals and researchers. People with hyperempathy may experience others' emotions so intensely that it can be difficult to distinguish between their own feelings and someone else's. While specific population estimates vary, some sources suggest that a significant number of individuals on the autism spectrum report experiencing hyperempathy.

Hypermnesia

Hypermnesia is an abnormally vivid and precise memory or recall of past experiences, often occurring under specific conditions like hypnosis, mental disorders, or moments of trauma. It represents an extreme enhancement of memory function, where previously forgotten or inaccessible information is vividly remembered with unusual clarity. 

Hyperthymesia / Highly Superior Autobiographical Memory (HSAM)

People with hyperthymesia, also known as Highly Superior Autobiographical Memory (HSAM), possess an extraordinary ability to recall vast amounts of personal life experiences in vivid detail. This rare condition is specific to autobiographical memory, meaning these individuals have average or even below-average ability to memorise new information or impersonal facts, unlike other forms of exceptional memory. It is considered a distinct subtype of autobiographical hypermnesia. 

Hyperphantasia

The opposite of aphantasia, hyperphantasia describes an ability to form extremely vivid mental imagery. Defined by Francis Galton, it has been recognised since 1880. Iriginally encompassing visual imagery, it is now applied across all mental imagery modalities. People with hyperphantasia may experience imagery as intensely as real perception. Around 10-15% of the population is estimated to have visual hyperphantasia.

Hypnagogic Hallucination

A sensory experience that occurs during the transition from wakefulness to sleep. These hallucinations can involve visual, auditory, tactile, or other sensory perceptions and often feel vivid and realistic. Unlike dreams, hypnagogic hallucinations happen while a person is still partially awake and aware. They are commonly associated with sleep disorders like narcolepsy but can also occur in healthy individuals.

Hypophantasia

A mild or reduced ability to form mental images, falling between aphantasia and typical mental imagery abilities. Defined by the Aphantasia Network in 2025. There are no exact prevalence statistics, but it is considered more common than aphantasia. Newly defined by the aphantasia researchers in 2025.

Imageless Seeing

Imageless seeing is the experience of seeing (of looking at, of visually apprehending) in inner experience, except that the thing seen (usually called the image) is not itself directly in awareness. Instead, there is a sense of visual perception or knowing without a distinct or structured mental imag

Imagery Vividness

A spectrum describing how clear, detailed, and intense mental images appear, ranging from no imagery (aphantasia) to highly detailed and immersive imagery (hyperphantasia). This is applied across all types of mental imagery, both those scientifically defined and those acknowledged by the MIR.

Imagination

The phenomenon of mentally generating images, ideas, or concepts beyond immediate sensory input, varying in vividness and frequency among individuals. Some people experience highly detailed and immersive mental imagery, while others have a more abstract or faint sense of visualisation. Imagination is considered a key component of creativity, problem-solving, and future planning by researchers.

Inner Hearing or Inner Ear

The phenomenon of internal sound, which varies in intensity and frequency among individuals. Some people experience a rich inner auditory world, including internal dialogue, music, or imagined sounds, while others have little to no auditory imagery. Those who lack an inner ear entirely experience a condition termed anauralia.

Inner Voice, Covert Speech or Verbal Thinking

The phenomenon of internal dialogue or self-talk, which varies in intensity and frequency among individuals. Some people experience a constant inner monologue, a few detail their inner voice to be silent, while others rarely, if ever, think in words. A lack of an inner voice is term anendophasia. The inner voice is considered Intraphonic Imagery by the MIR.

Integrated Intelligence Theory (IIT)

A theoretical framework that attempts to explain the nature of consciousness. It proposes that consciousness arises from the integration of information within a system—meaning a system is conscious if it contains a high level of both information differentiation (complexity) and integration (unity). According to IIT, the more interconnected and unified the information processing, the higher the level of consciousness. This theory has been applied to understanding brain activity, particularly in altered states of consciousness such as dreams, anesthesia, and near-death experiences.

Intelligence or Intelligences

The ability to acquire, apply, and adapt knowledge and skills across various contexts. According to Gardner’s theory of multiple intelligences, 1983, intelligence is not a single general ability but a set of distinct types. These include linguistic, logical-mathematical, spatial, musical, bodily-kinesthetic, interpersonal, intrapersonal, and naturalistic intelligences. Each type reflects a different way of processing information and solving problems, contributing to a more holistic understanding of human behaviour.

Instinct and Intuition

The active process of instinct and intuition, as defined by the MIR. Instinct is the body’s automatic and immediate response to stimuli, while intuition—such as aha moments—are a subconscious or immediate understanding of something without conscious reasoning. It is the intuitive imagery that represents those instinctive processes, just as visual imagery arises from visual perception.

Involuntary Imagery

Mental imagery that comes to conscious awareness spontaneously without conscious control. These can include flashbacks, daydreams, intrusive thoughts, or hallucinations, often triggered by emotions, memories, or external stimuli. Involuntary imagery plays a role in creativity, PTSD, and various neurological conditions.

Lucid Dream

A type of dream in which the dreamer becomes aware of that they are dreaming while still asleep, defined in 1913 by van Eeden. This awareness can range from a faint recognition of the dream state to full control over the dream’s events, environment, and characters. Lucid dreams typically occur during REM (rapid eye movement) sleep and can be influenced by techniques such as reality testing or meditation. 

Mental Feeling

Mental feeling is the direct, nonverbal sense of awareness or knowing that arises without words or concrete imagery. It is the subtle, felt experience of meaning, recognition, or realisation—distinct from emotion—often accompanying intuition, understanding, or cognitive shifts.

Mental Imagery or Imagery

The ability to create imagined experiences in the mind without direct external input. It is a complex and little-understood system, with five recognised types: visual, auditory, motor, olfactory, and gustatory imagery. Mental imagery plays a key role in cognition, with significant variation between individuals. 

Mind’s Eye

A metaphorical term for the ability to experience mental imagery, often associated with visual imagery specifically, even in the absence of actual visual input. While most people can access some degree of mental imagery through their mind’s eye, its clarity and vividness vary widely from person to person.

Multisensory Aphantasia

The inability to generate mental imagery across multiple sensory modalities, including visual, auditory, motor, olfactory, and gustatory imagery. This condition affects the ability to create imagined experiences in the mind, impacting memory, creativity, and cognitive processing. Mental imagery varies significantly among individuals, and multisensory aphantasia remains an area of ongoing research.

Near-Death Experience (NDE) or Out-of-Body Experience (OBE)

A near-death experience is a profound psychological event that occurs when an individual is close to death or in a life-threatening situation. These experiences often involve sensations such as detachment from the body, feelings of peace, visions of light, or encounters with otherworldly beings. Studies suggest that NDEs share similarities with Out-of-Body Experiences (OBEs) during lucid dream states, deep meditative states and psychedelic experiences. Research indicates that altered brain activity during these events may contribute to heightened consciousness and vivid sensory perceptions.

Neurodiverse vs Neurodivergent

Neurodiverse is a descriptive term used to refer to a group of people who include individuals with different types of neurocognitive functioning—such as those who are autistic, ADHD, dyslexic, and neurotypical. A group can be neurodiverse; a single person is not described as "neurodiverse." 

Neurodivergent refers to an individual whose cognitive functioning differs from what is considered typical or "neurotypical." Coined by Kassiane Asasumasu, it is an identity-affirming term used by individuals with conditions like autism, ADHD, dyslexia, and others. While “neurodiverse” highlights group variation, “neurodivergent” recognises individual differences from the neurological norm.

Neurodiversity

The concept that variations in cognitive functioning, such as differences in perception, thinking, learning, and sensory processing, are natural and valuable aspects of human diversity. Defined by Singer in 1998. Neurodiversity promotes the acceptance and inclusion of diverse neurological experiences, recognising that no single way of thinking or processing information is inherently superior.

Nonverbal Thinking or Thought

Nonverbal thinking or thought refers to thinking that occurs without the use of words or language. It can take the form of images, emotions, sensations, or abstract intuitions, often seen in activities like visualising a concept, feeling an idea instinctively, or solving problems through patterns rather than verbal reasoning.

Perception or Perceptual Experience

The process of experiencing and interpreting sensory information to construct our reality. It is deeply rooted in direct perceptual experience—what we see, hear, touch, taste, and smell—while also being shaped by cognitive factors such as attention, memory, and expectation. Emotions, past experiences, and subconscious processes influence how we perceive and make sense of the world around us.

Phantom Limb Syndrome (PLS)

Phantom Limb Syndrome (PLS) is the sensation that a missing or amputated limb is still present, often accompanied by feelings of movement, pressure, or pain. PLS involves the brain’s persistent representation of the missing limb, leading to vivid sensory experiences. Mental imagery techniques, such as visualising movement or engaging in mirror therapy, can help rewire neural pathways, reduce phantom sensations, and alleviate pain by reshaping how the brain interprets signals from the absent limb.

Phantasia

A term referring to the normal range of mental imagery, where individuals can voluntarily generate images with moderate clarity and control. People with phantasia can visualise objects, scenes, or events to varying degrees but do not experience the extreme ends of the imagery spectrum.

Post Traumatic-Stress Disorder (PTSD)

Post-traumatic stress disorder (PTSD) was first defined in 1980 in the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III).  PTSD is an injury affecting the areas that regulate the "fight or flight" response, caused by prolonged or extreme stress or trauma. It alters neural function, particularly in the amygdala, hippocampus, and prefrontal cortex, leading to heightened threat responses, intrusive imagery, emotional dysregulation, and physiological changes. 

Precognition or Premonition

The ability to perceive or gain knowledge of future events that could not be known through normal means. This form of extrasensory perception (ESP) allows an individual to foresee or describe occurrences before they happen, without any logical basis or prior indication (retrospective imagery). The first formal studies of precognition were conducted in the late 1800s by the Society for Psychical Research, UK.

Progressive Aphantasia

A 2022 commentary by Sitek and Konieczna proposes that progressive aphantasia—a gradual decline in the ability to create mental images—may serve as an early indicator of neurodegenerative diseases, such as dementia. They suggest that changes in mental imagery capabilities could precede other cognitive symptoms, highlighting the potential importance of monitoring such changes in clinical assessments.

Prosopagnosia or Face Blindness

Prosopagnosia, also called face blindness, is a condition where you have difficulty recognising people's faces. German neurologist Joachim Bodamerr coined the term "prosopagnosia" in 1947 to describe the inability to recognise faces. The term comes from the Greek words prosopon, meaning "face", and agnosia, meaning "lack of knowledge.

Quasi-Perceptual Conscious Experience

A mental experience that resembles perception but occurs without direct sensory input. These experiences include mental imagery, dreams, hallucinations, and visualizations, where the mind generates sensations similar to real perception. Unlike actual perception, quasi-perceptual experiences are internally constructed and can vary in vividness and control.

Quintessence

In the context of the mind, quintessence could refer to the purest or most fundamental aspect of consciousness, thought, or intellect. It might represent the essence of wisdom, awareness, or the highest form of mental clarity. Philosophically, it could be seen as the ultimate truth or the core of human cognition beyond fleeting thoughts and emotions.

Retrocognition or Postcognition

The ability to perceive or gain knowledge of past events that could not have been learned through normal means (prospective imagery). This form of extrasensory perception (ESP) allows an individual to experience or describe historical events, personal past experiences, or unknown past occurrences without prior exposure.  The first studies of precognition were conducted in the late 1800s by the Society for Psychical Research, UK.

Schizophrenia

Schizophrenia can involve hallucinations and disruptions in mental imagery, leading to intrusive, involuntary visual or auditory hallucinations that feel as vivid as real perceptions. While some individuals may experience hyperactive and uncontrollable mental imagery, others may have impaired voluntary imagery, struggling to visualise or recall mental pictures. These distortions in internal perception contribute to difficulties in distinguishing imagination from reality.

Sense or Sensory Experience

A sensory experience refers to the perception of stimuli through the five primary senses: sight, hearing, touch, taste, and smell. Modern theories suggest humans may have up to 20 or more senses, including balance (vestibular), body awareness (proprioception), internal sensations (interoception), pain perception (nociception), temperature detection (thermoception), and time perception. These senses allow individuals to interpret and respond to both external and internal environments.

Sensorimotor Dreaming or Tactile Dreaming

When dreams feel physically real, it is often referred to as sensorimotor dreaming or somatosensory dreaming. This occurs when sensations such as touch, pain, temperature, pressure, or movement are vividly experienced in a dream. Can be associated with lucid dreams and false awakenings.

Severely Deficient Autobiographical Memory (SDAM)

A condition characterised by difficulty recalling personal memories in detail, despite having intact factual memory. McKinnon discovered and defined  SDAM in 1977. SDAM is linked to aphantasia in some cases, though not all individuals with SDAM have aphantasia. The prevalence is currently unknown.

Spatial Intelligence

Spatial intelligence refers to the ability to manipulate, and understand the spatial relationships between objects in three-dimensional space. Central to this ability is mental imagery—the process of generating and transforming mental representations in sensory form, often described as using the "mind’s eye." Mental imagery enables tasks such as mentally rotating an object to view it from different angles or navigating a complex environment using a mental map. Individuals with aphantasia perform just as well as the general population on spatial and mental rotation tasks. This suggests that while mental imagery is a common mechanism for spatial reasoning, it may not be the only one, and spatial intelligence can operate through alternative cognitive strategies.

Synesthesia

A neurological condition where stimulation of one sensory or cognitive pathway leads to involuntary experiences in another (e.g., seeing colors when hearing music). Recognised by Galton in 1880 and defined by Millet in 1892. It is estimated to occur in 4% of the population, though some forms may be more common.

Unconscious Imagery

Mental imagery that occurs without conscious awareness or direct sensory input but without feedback from the main mental senses. It is not an experience that is functionally perceived in the "mind's eye". Research suggests that even in individuals who report no conscious imagery, such as those with aphantasia, the brain's visual cortex may still process imagery-related information unconsciously. This implicit processing can influence a person's behavior, but it does not become a part of their conscious experience.

Unconsciousness

Unconsciousness is the state of lacking awareness of one’s thoughts, emotions, or surroundings. In this state, an individual cannot perceive or respond to external stimuli, and mental processes occur automatically without deliberate control. It can result from sleep, anesthesia, or medical conditions. Unlike consciousness, which involves active awareness and reflection, unconsciousness involves passive, automatic functions essential for basic survival, such as breathing and heart regulation.

Unconscious Perceptual Experiences or Thoughts

Imagery without deliberate awareness or intentional control. These include automatic perception, intuitive decision-making, mental imagery, and implicit thought processes. Unlike conscious cognition, these experiences shape behaviour, emotions, and judgments without requiring focused attention.

Unworded Speech or the Silent Inner Voice

Unworded speech refers to the formation of thoughts in a speech-like structure but without actual words. It might involve abstract linguistic patterns, rhythmic flows, or a sense of verbal intention without inner phonetic articulation.

Voluntary Imagery

Mental images that are deliberately generated and controlled by conscious effort and awareness. This includes visualising scenarios, recalling memories, or imagining future events, often used in problem-solving, creativity, meditation, and sports performance. Voluntary imagery is essential for planning, learning, and mental rehearsal.

Worded Thinking or Verbal Thought

Verbal thought, or worded thinking, is the process of thinking in clearly formed words and sentences, either as an internal monologue or structured linguistic reasoning. It involves the use of language to shape, analyze, and express thoughts within the mind.

Wordless Thinking or Unsymbolised Thought

Wordless thinking is the process of cognition occurring without inner speech, encompassing unsymbolised thought—also called intuitive imagery. Intuitive imagery is the direct, nonverbal experience of meaning through subtle mental impressions, patterns, or feelings rather than structured representations. It is a form of pure knowing, where understanding arises without words, images, or any defined sensory form.

Yedasentience or 'Knowing'

Yedasentience is a term given to the 'knowing and feeling' mind. It is the internally generated feeling of knowing, signaling when a thought process or action has reached completion. It plays a crucial role in decision-making, memory confidence, and regulating information-seeking. Yedasentience helps determine when to stop seeking information or pursuing a task—as defined by Szechtman & Woody in 2002.