The Research Behind
the Spectrum

The first systematic study of mental imagery variation. Galton sent questionnaires asking men to describe their breakfast table from memory and found enormous variation - some described vivid pictures, others had no visual experience at all. His paper "Statistics of Mental Imagery" (Mind, 1880) is the first empirical record of what we now call the imagination spectrum. The finding was largely ignored for over a century.

The Vividness of Visual Imagery Questionnaire (VVIQ) is created by David Marks - a 16-item psychometric scale asking people to rate the vividness of mental images on a 1–5 scale. Published in the British Journal of Psychology, it becomes the gold-standard measure of imagery vividness and remains widely used today. doi:10.1111/j.2044-8295.1973.tb01322.x →

Adam Zeman at the University of Exeter publishes the case of Patient MX - a man who lost voluntary visual imagery following cardiac surgery but retained normal visual perception. Published in Neuropsychologia, this paper formally identifies voluntary imagery generation as a distinct cognitive function that can be selectively lost. It plants the seed for everything that follows. doi:10.1016/j.neuropsychologia.2009.08.024 →

The landmark paper "Lives without imagery - Congenital aphantasia" is published in Cortex. After BBC coverage of Patient MX, Zeman received over 10,000 emails from people with congenital aphantasia who had never had a name for their experience. The term aphantasia - from the Greek for "without imagination" - is introduced. The field of imagery vividness research is permanently changed. doi:10.1016/j.cortex.2015.05.019 →

A striking finding in Cerebral Cortex: people with stronger, more vivid mental imagery actually have a smaller primary visual cortex surface area, but a larger frontal cortex. The explanation is counterintuitive - a smaller V1 may be less "noisy," making top-down imagery signals from the frontal cortex stand out more clearly. This is among the first structural brain findings relevant to understanding why some people (hyperphantasics) have significantly more vivid imagery than others. doi:10.1093/cercor/bhv186 →

Rebecca Keogh and Joel Pearson at UNSW publish the first objective (non-self-report) evidence of aphantasia using binocular rivalry - a technique where different images are shown to each eye. Typical imagers can use mental imagery to bias which image they perceive; aphantasics show no such effect, confirming the absence of imagery is a genuine perceptual phenomenon, not just a reporting difference. Published in Cortex. doi:10.1016/j.cortex.2017.10.012 →

A combined fMRI study and literature review in Cortex finds that higher imagery vividness specifically correlates with greater activation of higher-order visual areas, the limbic system, and the default mode network - regions associated with emotional processing, memory, and self-referential thought. This helps explain why hyperphantasics report stronger emotional responses to imagination, more vivid autobiographical memories, and why their internal cinema feels so immersive: the brain's emotional and memory systems are recruited alongside the visual ones. doi:10.1016/j.cortex.2017.09.014 →

Joel Pearson publishes a major review in Nature Reviews Neuroscience synthesising decades of imagery research, providing a framework for understanding how mental imagery works neurally and what its failure in aphantasia reveals about the visual system. A foundational read for anyone going deeper into the science. doi:10.1038/s41583-019-0202-9 →

A large-scale study in Cortex characterises the full spectrum from aphantasia to hyperphantasia across 2,000+ participants. It formally introduces "hyperphantasia" as a term, estimates prevalence (~4% aphantasia, ~3% hyperphantasia), and identifies psychological associations - including links to scientific occupations (aphantasia) and creative professions (hyperphantasia). doi:10.1016/j.cortex.2020.04.003 →

A study in Scientific Reports provides a detailed cognitive profile of aphantasia across multiple senses - finding that aphantasia often extends beyond vision to affect auditory, olfactory, and tactile imagery. It also confirms that most aphantasics do experience visual dreams, suggesting the voluntary/involuntary imagery distinction is neurologically meaningful. doi:10.1038/s41598-020-65705-7 →

Published in eLife, this study provides the first causal (not merely correlational) evidence that visual cortex excitability controls imagery strength. Using tDCS to temporarily reduce visual cortex excitability, imagery strength measurably increased - and vice versa. Frontal cortex played the opposite role: higher frontal excitability meant stronger imagery. This is a landmark result for understanding hyperphantasia: it suggests that the hyperphantasic brain may have a particularly effective top-down frontal-to-visual pathway, with a visual cortex that responds readily to internally generated signals. Crucially, this means imagery vividness isn't fixed - it can, in principle, be modulated. doi:10.7554/eLife.50232 →

The first systematic neuropsychological and brain imaging study directly comparing aphantasia, hyperphantasia, and midrange imagery across 69 participants. For hyperphantasia specifically: participants significantly outperformed controls on autobiographical memory and imagination tasks; showed higher scores on the personality trait of Openness; demonstrated stronger resting-state connectivity between prefrontal cortex and the visual network; and showed greater anterior parietal activation during active visualisation of famous faces and places. This is the most detailed neuropsychological portrait of hyperphantasia to date. Published in Cerebral Cortex Communications (open access). doi:10.1093/texcom/tgab035 →

A study published in Cortex asks aphantasics and typical imagers to draw objects from memory. Aphantasics show significantly reduced object detail (colour, texture, specific features) but comparable spatial accuracy - suggesting that object-based and spatial memory rely on at least partially separate systems, and that aphantasia specifically disrupts the visual-object component. doi:10.1016/j.cortex.2020.11.014 →

Published in Proceedings of the Royal Society B, this study tests whether mental imagery amplifies emotional responses. Aphantasics show significantly reduced physiological fear responses to imagery-based fear induction - but comparable responses to real perceptual stimuli. This provides evidence for the "emotional amplification" theory of imagery, and has clinical implications for anxiety and PTSD treatment. doi:10.1098/rspb.2021.0267 →

A large general population study in Consciousness and Cognition refines aphantasia prevalence estimates, finding approximately 0.7–4% depending on threshold used (VVIQ score of 16 vs. ≤32). Also identifies multi-sensory aphantasia as the norm rather than the exception, and finds aphantasia is more common in males and associated with STEM occupations. doi:10.1016/j.concog.2021.103243 →

Researchers at the University of Liverpool and University of Oxford set out to replicate a highly-cited 2007 study on imagery vividness and perceptual interference - and found they couldn't. What they found instead was more significant: a new dimension of imagery they named prophantasia (from Greek: "pro" = in front of, "phantasia" = imagination). While vividness describes the intensity of mental imagery, prophantasia describes its location - whether imagery is experienced internally (in the mind) or externally (overlaid onto the visual world, like AR). Their "externalism" measure predicted perceptual interference effects far better than vividness alone, and explains why some people score unexpectedly low on the VVIQ despite having powerful imagery - they're looking for the image in the wrong place. Published in the Journal of Experimental Psychology: General. doi:10.1037/xge0001756 →

Zeman's comprehensive review in Trends in Cognitive Sciences synthesises ~50 studies published since 2015. Key conclusions: neither aphantasia nor hyperphantasia is a disorder; effects on functioning are more subtle than expected; aphantasics often retain visual dreaming; there are subtypes within aphantasia (extreme vs moderate, global vs unisensory). Acknowledged as out of date within months - a sign of how fast the field is moving. doi:10.1016/j.tics.2024.02.007 →

A provocative theoretical paper in Trends in Cognitive Sciences proposes that aphantasia may be a form of "imagery blindsight" - where visual processing occurs at a neural level without reaching conscious awareness. This challenges simple "no imagery" accounts and aligns aphantasia with broader debates about the relationship between perception and consciousness. doi:10.1016/j.tics.2024.11.002 →

A landmark neuroimaging study using ultra-high-field 7-Tesla fMRI achieves millimetre-scale resolution of visual cortex activity during imagery tasks in aphantasics and typical imagers. Provides the most detailed brain-level picture yet of where and how imagery generation differs. Published in Cortex. Represents a step-change in the precision available to imagery researchers. doi:10.1016/j.cortex.2025.01.013 →

Zeman publishes a forward-looking review in Neuropsychologia noting that over 50 new papers appeared in the year after his 2024 Trends in Cognitive Sciences review - a measure of how rapidly the field is growing. Identifies key open questions: whether imagery vividness is continuous or categorical; the relationship with SDAM; the mechanisms behind preserved dreaming in aphantasia; and the clinical potential of imagery research. View at ScienceDirect →