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TITLE Blind Mind's Eye

AUTHORS Zeman, A

JOURNAL American Scientist Magazine

DEPOSITED IN ORE 08 June 2021

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People with aphantasia cannot visualize imagery, a trait that highlights the complexities of imagination and mental representation.

Adam Zeman

hich is darker: the green “hear” the sound of distant thunder, a map that we have memorized, we of grass or the green of a “feel” the touch of velvet, or imagine answer more swiftly if they lie close to- pine tree? Does a squir- running for a bus by engaging audi- gether rather than far apart, as if we rel have a short or a long tory, tactile, and motor imagery, respec- were scanning the map with our eyes Wtail? Is a walnut larger than a hazelnut? tively. Olfactory imagery is more elu- before we respond; in deciding whether Do Labradors have rounded ears? To sive, but many of us can relish the scent one object is a rotated version of the oth- answer questions such as these, you of a rose or shrink from the smell of er, the timing of the decision depends probably summoned up images of the sewage. To some degree, we can evoke on the extent of the rotation. A beau- mentioned items to inspect them in absent emotions, imagining a breath tifully simple observation epitomizes your “mind’s eye.” When you enjoy of sadness or a sudden jolt of surprise. work along these lines: If visualizing is a novel, you likely come away with Although this article focuses on visual really like seeing, visualizing something a visual impression of the characters imagery, the broad principles seem to bright should cause a constriction of the and scenes described—which can apply to imagery of all types. pupil, as would occur when looking lead to that familiar disappointment Experiences of imagery are ubiqui- at something bright. Bruno Laeng at if the book is turned into a movie: “He tous. They contribute to our recollection the University of Oslo has shown that, looked nothing like I’d imagined him!” of the past (think of your last holiday) indeed, if we switch our mental image Most of us can conjure images to and our anticipation of the future (how from a bright sky to a night sky or a order: Visualize the Sun rising above will you spend next weekend?). They cloudy one, the pupil duly dilates (see the horizon into a misty sky—or your figure in our daydreams and our night figure at the top of page 112). kitchen table as you left it this morn- dreams. They have been implicated in But there is more to imagery than it ing. But it turns out that 1 to 3 per- creative work in both the sciences and being simply “weak perception.” Let’s cent of the population entirely lack the the arts. Albert Einstein wrote: “I very say that I ask you to imagine a tulip, ability to visualize—a condition called rarely think in words at all,” relying and you succeed—what color was it, by aphantasia—whereas others have hyper instead on “more or less clear images the way?—you engage a whole team of phantasia and experience imagery as which can be voluntarily ‘reproduced’ more basic cognitive abilities: You must vivid as actual sight. These imagery and combined. . . .” The novelist Joseph be awake and attentive, you require vividness extremes are prime examples Conrad emphasized the importance of your command of the English language of invisible differences that are easily imagery to his craft: “My task . . . is, by to decode the instruction, you need overlooked but are salient features of the power of the written word to make your memory to retrieve your knowl- the inner lives of those concerned. Un- you hear, to make you feel—it is, before edge of tulips and their appearance, derstanding how such differences arise all, to make you see.” you need to use your executive function can help us learn about the many ways Research over the past century has to orchestrate the whole process, and the mind can implement imagination taught us much about the psychology you use your perceptual system to gen- and mental representation. of imagery generally and its basis in the erate the sense of “looking at” a tulip. brain. An impressive series of experi- This description reminds us that, like The Science of Imagery ments by Stanford University psycholo- any cognitive act, forming an image is Imagery involves the sensory experi- gist Roger Shepard, Harvard University a process rather than an instantaneous ence of items in their absence: When neuroscientist Stephen Kosslyn, and event. A measurable amount of time we visualize a pine tree or the rising others showed that imagery is indeed, passes between receiving the instruc- Sun, most of us have an experience that as intuition might suggest, an echo of tion to “visualize a tulip” and becom- is a bit like seeing. But we can form im- perception. If we are asked to shift our ing able to inspect and manipulate its agery in other sense modalities too: We mental gaze between two objects on image in the mind’s eye. On the basis

QUICK TAKE A condition called aphantasia affects 1 to A survey about imagery vividness from Aphantasia does not imply a lack of imagi- 3 percent of the population. Aphantasics lack 1880 was the first to document the condition, nation, which indicates that the brain has a the ability to visualize imagery—a term that but it remained a little-studied phenomenon wide range of methods for cognitive represen- includes all the senses, not just sight. until the past few decades. tation, some more abstract than experiential.

110 American Scientist, Volume 109 © 2021 Sigma Xi, The Scientific Research Honor Society. Reproduction with permission only. Contact [email protected]. It is now almost half a century since one other fascinating line of evidence began to illuminate the science of imagery. Functional brain imaging relies on the simple principle that the brain is like muscle: When it becomes active in a task, the blood flow to activated regions ramps up. We can observe this change in several ways, most com- monly using magnetic resonance imaging that is sensitive to local changes in oxygen concentrations. Two years ago my colleague Crawford Winlove identified 40 studies that had examined brain activation during imagery tasks. The regions he and others have identified (see figure at the bottom of page 112) are in keeping with the cognitive processes required to call a tulip to the mind’s eye—areas in the frontal and parietal lobes linked to cognitive control, atten- tion, and eye movements; areas linked to language processing; areas involved with memory; and visual cortices in the occipital and temporal lobes. The leading edge of such research is now focused on “mind reading,” which is the effort to decode the contents of the mind’s eye using brain-imaging data. Studies examining the time course of acts of visualization in the brain high- light another, intuitively obvious, difference between imagery and perception. When we see, information streams in from the eyes to the brain, driving activity that spreads through the visual system and deep into the brain, allow- ing us, among other things, to recognize what we see. Visualization is “vision in reverse”: The brain begins with a decision or instruction—”imagine a tulip”—and uses its stored knowledge of appearances to drive activity within the visual system that leads to the experience of imagery. Imagery, in brief, allows us to simu- Artefact/Alamy Stock Photo late sensory experience “offline,” en- Wonderland by Adelaide Claxton (1841–1927) depicts the mental imagery (here, a smoky imag- abling at least a partial reenactment of inary figure) that our brains regularly conjure up while reading or while doing any other task our past encounters with the world. where we are asked to visualize. People with aphantasia cannot create these mental images. The usual explanation for why we have imagery is that it ultimately enhances of a series of behavioral experiments images tend to fade rapidly, probably our ability to predict the future and act like those described above that he and because the visual brain is designed effectively within it. This purpose may his team undertook in the 1980s, Koss- to deal with rapidly changing scenes. be true, but recent findings somewhat lyn described four key processing steps Keeping an image in mind requires complicate this story. in our engagement with images. First, maintenance, Kosslyn’s second process- images must be generated: This step in- ing step. If we want to use an image to Rediscovering Aphantasia volves mobilizing information about answer a specific question—does your Sir Francis Galton was a Victorian sci- how things look and using it to create tulip have a long stem?—we need to entist with a passion for measurement, a representation of the visualized item inspect it, which is the third step; if we which was misapplied in his role in in what he called the “visual buffer,” want to manipulate the image, such as the development of eugenics. But his a broad description for relevant, visu- twirling our tulip, some transformation “breakfast table questionnaire,” pub- ally oriented regions of the brain. These is called for, the final step. lished in 1880, was probably the first www.americanscientist.org © 2021 Sigma Xi, The Scientific Research Honor Society. Reproduction 2021 March–April 111 with permission only. Contact [email protected]. .8 circulated his questionnaire to 100 colleagues, mostly scientists, classifying .6 their responses into those where “the faculty is very high,” mediocre, or “at the lowest.” To his astonishment, many .4 of these “men of science” protested that “mental imagery was unknown to them . . . they had no more notion of its true .2 nature than a colour-blind man, who has not discerned his deficit, has of the true nature of colour.” When he began 0 to sample persons “in general society,” however, he found “an entirely different –.2 disposition to prevail. Many men, and a yet larger number of women, and many pupillary change (pixels) boys and girls, declared that they ha- –.4 bitually saw mental imagery, and that it was perfectly distinct to them and full of colour.” There were also some notable –.6 exceptions to the rule among his scientific friends. A certain Charles Darwin, Galton’s much esteemed cousin, re- –.8 sunny night cloudy face in face in dark sponded that his image of the breakfast day sky sky sunlight shade room table included some objects “as distinct type of scene as if I had photos before me.” Adapted from B. Laeng et al., 2014. Galton’s questionnaire spawned Imagery studies show that imagination can cause physical responses, demonstrating that visu- many descendants. We have used psy- alization is connected to vision. In this case, data show that people’s pupil dilation will change chologist David Marks’s Vividness of as they visualize brighter or darker imagery. Visual Imagery Questionnaire (VVIQ) systematic attempt to measure the to it this morning—and consider care- in our own work (see figure on page 113). vividness of imagery. The question- fully the picture that rises before your This questionnaire asks for vividness naire invited participants to “think mind’s eye.” They were asked to com- judgments about images of 16 scenes of some definite object—suppose it is ment on its degree of illumination, that are rated from “no image at all, you your breakfast table as you sat down definition, and coloring. Galton initially only ‘know’ that you are thinking of the object,” scoring 1/5, to “perfectly clear and as vivid as real seeing,” scoring full marks. Galton’s intriguing observation that for some the “power of visualization was zero” was almost entirely neglected over the following century, despite a great flowering of research on imagery more generally. A single Amer- ican psychologist, Bill Faw, researched the topic in the past few decades, esti- mating that around 2 to 3 percent of his undergraduate students, like Faw him- self, were “wakeful non-imagers.” Oc- casionally neurologists, starting in 1883 with Jean Martin Charcot, the father of French neurology, encountered patients who lost the ability to visualize following brain injuries or strokes, and a few psychiatrists, such as Jules Cotard in 1882, recognized that mood disorders could cause a dimming of imagery and sometimes its disappearance. But most research examining imagery vividness Adapted from C. Winlove et al., 2018. focused on people with mid-range viv- Combined results from hundreds of individuals show the brain areas consistently activated while visualizing. Those in the frontal and parietal lobes are linked to cognitive control, at- idness scores. It suggested that these tention, eye movements, language processing, and memory, whereas areas in the occipital scores were reasonably consistent over and temporal lobes are visual. The mesh at lower left allows standardized mapping of brain time, but they showed rather modest, regions. The arrow at top left indicates the insula, an area involved in sensation that normally unexciting correlations with other psy- would be obscured by other brain regions. chological abilities.

The Vividness of Visual Imagery Question- naire (VVIQ) asks responders to visualize a number of unfolding scenes, such as: The Sun rises above the horizon into a hazy sky, the sky clears and surrounds the Sun with blueness, clouds form and a storm blows up with flashes of lightning, then a rain- bow appears. Responders are then asked to rate their imagery from 1 to 5, with 5 being perfectly clear and as vivid as real seeing, 4 being clear and reasonably vivid, 3 being moderately clear and lively, 2 being vague and dim, and 1 being no image at all, just an awareness that you are thinking about 2 1 this subject. Barbara Aulicino

The first time I knowingly encoun- correlate for the subtle but distinctive lack of wakeful imagery. About half of tered a person without the ability to change in experience that he reported. them told us that they lacked imagery create imagery was in 2003. Identi- I found MX’s case fascinating but in all sense modalities, not just the vi- fied only by the code MX for research did not anticipate what followed. The sual. Some described affected relatives. purposes, he was a delightful retired science journalist Carl Zimmer wrote Oddly, all but two were men. surveyor in his mid-60s. Not long be- an accessible account of our research I felt that this phenomenon de- fore I met him, he had undergone a in Discover magazine in 2010. Over the served an appropriate name. The cardiac procedure. Shortly afterward next few years, my colleagues Sergio terms used in the neurological litera- he realized that he could no longer vi- Della Sala and Michaela Dewar and ture, such as defective revisualization sualize: He had previously relished his I were contacted by 21 people who and visual irreminiscence, were un- active mind’s eye, for example, call- recognized themselves in Zimmer’s wieldy. I consulted a colleague trained ing to mind images of friends, family, and places he had visited as he settled down to sleep. His dreams became avisual after the procedure, and he Aristotle’s name for the mind’s eye was found that when he read, the novel would no longer create a visual world. phantasia, so we prefixed ana, denoting His vision, by contrast, appeared entirely unaffected. absence, to coin the term aphantasia. MX’s account of his unusual symp- toms was so compelling that we ultimately studied his brain activation in description of MX—with the key dif- in classical philosophy, David Mitchell a visualization task using functional ference that they had never been able of the New College of Humanities in magnetic resonance imaging (see figure to visualize. Their accounts were quite London, who suggested that we bor- on page 114). When MX looked at fa- consistent. They usually became aware row from Aristotle, one of the Greek mous faces, his pattern of brain activ- of this idiosyncrasy in their psycho- fathers of philosophy. Aristotle’s name ity was normal, but when he tried to logical makeup in early adulthood. It for the mind’s eye, in his work De visualize them, he failed to activate vi- intrigued rather than dismayed them. Anima (Of the Soul) was , or sual brain regions that came into play Most respondents described rather phantasia. We prefixed an a, denoting in our control participants. This dif- poor autobiographical memory. Most absence, to coin the termφαντασία aphantasia, ference suggested a satisfying neural still dreamed visually despite their the lack of a mind’s eye. Words are

1 2 3

A patient who lost the ability to visualize after a surgery underwent functional magnetic resonance imagery of his brain activation during a visualization task. When he visualized faces, he activated visual brain regions less than normal (above), but he activated more strongly brain areas that likely broadly indicate more mental effort (below). 1

Adapted from A. Zeman et al., 2010. powerful tools. To my surprise, this transcendent warmth I’ve only known Vividness Extremes simple coinage, published in a letter once before, when a dorky high school Our first finding echoed Galton’s obser- describing our 21 aphantasic contacts, outcast in Florida stumbled on a group vations about his scientific colleagues. triggered an avalanche of interest. of California programmers who just Although there are many exceptions to Widespread press coverage of the seemed to ‘get him.’ It’s the feeling of this rule, aphantasia is associated with a word and the phenomenon that it de- finding your people.” We had connect- bias toward mathematical and scientific scribes has since led around 14,000 peo- ed with an unmet need. occupations, whereas hyperphantasia ple to get in touch by email. The ma- Our flooded email inbox created a is associated with more traditionally jority have described various forms of unique opportunity for further re- creative trades. Next, we identified two aphantasia. Fewer people reported ex- search. With the help of a team of stu- areas of difficulty for many people with periences from the opposite end of the dent interns from the University of Ex- aphantasia: Approximately one-third vividness spectrum, with exceptionally eter, I responded to the emails pouring report poor autobiographical memo- vivid imagery; we termed this hyper in with a request to complete the VVIQ ry, whereas a (partially overlapping) phantasia. We were struck by the strong and another imagery questionnaire ex- third report a problem in recognizing emotion expressed in many of the mes- ploring a range of related topics. These faces; these complaints are rare among sages: “This is unbelievable. I’ve gone questions asked, for instance, how and people with hyperphantasia (see figure my entire life attempting to explain that when people recognized their “differ- at the top of page 115). These findings I cannot picture things in my head”; ence,” whether they dream in images, from the far extremes of imagery viv- “. . . a phenomenon that feels like a se- and whether they have trouble recall- idness harmonize with reports from cret I’ve been keeping my whole life”; ing episodes from their personal past. other researchers that, in general, hav- “so much of the world now makes This exercise has allowed us to give a ing more vivid imagery predicts richer, sense”; “the craziest thing is knowing preliminary description of the psycho- clearer, and less effortful recollection that I’m not alone.” The cofounder of logical significance of imagery extremes of autobiographical events. Similarly, Mozilla Firefox, Blake Ross, posted a from an analysis of 2,000 questionnaire a previous study of people with con feisty account of his self-discovery as pairs from people with lifelong aphan- genital prosopagnosia—a lifelong failure aphantasic that went viral: “I felt that tasia and 200 with hyperphantasia. to recognize faces—had indicated that

114 American Scientist, Volume 109 © 2021 Sigma Xi, The Scientific Research Honor Society. Reproduction with permission only. Contact [email protected]. 80 100 70 aphantasia 90 aphantasia hyperphantasia 80 hyperphantasia 60 controls 70 controls 50 60 40 40 30 50 30 20 20 percentage frequency percentage 10 frequency percentage 10 0 0 good bad normal unsure poor normal autobiographical memory type face recognition ability Adapted from A. Zeman et al., 2020. their visual imagery tends to be faint. A About a third of people with aphantasia report poor autobiographical memory, whereas fourth association kept cropping up in a partially overlapping third report problems recognizing faces; these complaints are rare our correspondence, although we had among people with hyperphantasia. not specifically asked about this trait in our questionnaire: Many people with extreme imagery report that other fam- but if they exist, their genetic back- aphantasia reported they were on the ily members are similarly affected, al- ground may well vary. autistic spectrum. At the opposite end lowing us to calculate a roughly tenfold of the spectrum, hyperphantasia ap- increase in risk compared with the gen- The Task of Triangulation peared to be linked to synesthesia —the eral population. It is too soon to judge The story I have told you so far has re- process by which some quality of expe- whether this increase has a genetic ba- lied on first-person evidence: what our rience, such as the sound of a vowel, is sis. We hope to find out, but this effort participants have told us about their accompanied by an involuntary, unre- will probably be hampered by a com- imagery and other aspects of their men- lated, secondary experience, such as a plexity that may well have occurred tal lives. This evidence is consistent: color (see “Synesthesia’s Altered Senses” to you. Aphantasia is almost certainly At around the time that we published in the July–August 2020 issue). not a single entity: It is a variation in our description of the psychological These associations were both intrigu- experience that can occur in a range features of imagery extremes, anoth- ing, raising questions about the under- of settings—for example, in associa- er research group, led by imagery relying mechanisms involved, and reas- tion with face recognition difficulty—or searcher Joel Pearson of the University suring: They suggested that rather than with lack of imagery in other senses. Its of New South Wales in Sydney, Austra- being isolated oddities, visual imagery subtypes have yet to be clearly defined; lia, described very similar findings. But extremes are part of a bigger psychological picture. Our hundredfold larger sample gave us an opportunity to ex- amine two other hints from our previous study of 21 participants. Around 60 percent of people with aphantasia reported visual dreams. This apparent discrepancy makes neurological sense, because the processes within the brain leading to dreaming and wakeful imagery are very different, so it is quite plau- sible that they should dissociate. People with aphantasia who dream avisually give fascinating descriptions of narra- tive, conceptual, and emotional dreams. Much as in our smaller study, around half of those with extreme imagery, both high and low, told us that all their senses were affected; for the remainder, some or all the other modalities of imagery were of normal vividness. This disparity suggests that both factors common to all Wilma Bainbridge at the University of Chicago and her colleagues took the approach of sense modalities and factors specific to quantifying aphantasia with drawing. Their study found that aphantasics lack object memory, but do not lack spatial memory. When the participants were shown a photograph each influence the vividness of imagery. of a real scene for 10 seconds and then asked to draw it from memory, aphantasics recalled Our estimates for the rates of ex- fewer objects in the scene, but had lower incidence of mistakenly adding objects not in the treme imagery in the community are photograph. However, when aphantasics were then asked to pick out the image of the scene about 1 to 3 percent for aphantasia, and they had been shown from a set of scenes, they did as well as controls, or people with aver- 3 to 11 percent for hyperphantasia, de- age imagery vividness. When the aphantasics were asked to copy that scene while looking pending on the threshold chosen for di- at the image, there was also no difference from controls. agnosis. Many of our participants with Bainbridge et al., 2021. W. Adapted from www.americanscientist.org © 2021 Sigma Xi, The Scientific Research Honor Society. Reproduction 2021 March–April 115 with permission only. Contact [email protected]. you may be skeptical about first-person than in people with aphantasia. Other people with aphantasia and hyperphan- evidence altogether. People are not en- candidate explanations include dif- tasia prompts some general reflections. tirely reliable witnesses of their mental ferences in the area of visual cortices, First, are aphantasia and hyper- lives. Descriptions of experience seem a which Pearson has shown to be related phantasia “disorders”? In general, I good point of departure for psychologi- to differences in the strength and ac- think not. They are intriguing varia- cal research. But if imagery extremes curacy of imagery using his weak- tions in human experience, analogous are significant, it should be possible to perception technique. There is also evi- to synesthesia, which, like aphantasia, triangulate these first-person reports dence that variation in the excitability affects around 2 percent of the popula- with more objective measurements, ap- of visual regions can influence imagery tion. Both extremes of imagery viv- plying both behavioral tests and neural, strength. These possibilities are not mu- idness have interesting psychological brain-based approaches. tually exclusive, and more than one of associations, but neither is a barrier to This work is underway. Pearson had these hypotheses may prove correct. leading a rich, creative, and fulfilling previously used the idea that imag- life. I suspect that the two extremes of ery is like weak perception to devel- Imagery Versus Imagination the vividness spectrum will prove to op an ingenious measure of imagery Imagination—defined as our ability have balanced advantages and disad- strength. Briefly, his method uses the to represent, reshape, and reconceive vantages. They are, however, occasion- finding that a visual image formed in things in their absence—is one of the ally symptomatic of disorder: Aphan- the mind’s eye can influence subse- defining powers of the human mind. tasia, for example, can sometimes quent perception in much the same Its central importance contributes to the result from a stroke, a head injury, or way as a faint visual stimulus pre- interest in imagery extremes, as imagery an episode of depression. So if some- sented externally. The extent of this is, for most of us, a prominent ingre- one who has previously had imagery influence can be measured to provide dient of our imaginings. The fortunate suddenly loses it, it’s reasonable to try a relatively objective estimate of imag- opportunity to study large numbers of to find out why. ery strength. In people with aphantasia, the influence is undetectable, sug- gesting that, indeed, they are failing to form visual images at all. control A second elegant experiment from 0.8 aphantasic Pearson’s lab is also telling. His team asked people with and without aphantasia to read a series of scary descriptions, such as a swimmer’s view of an approaching shark, which would evoke 0.4 vivid imagery in most of us. They found that people with aphantasia failed to show the marked change in skin conductance observed in control partici-

SCL shift from baseline ( microseconds) from SCL shift 0.0 pants without aphantasia (see figure at 20 40 60 80 100 right). This difference was not because of mean SCL an overall reduction in emotion, as the time (seconds) aphantasic participants showed a normal reaction to photos of scary scenes. My team has recently used standard 2.4 psychological tests to measure memory control and imagination in people with aphan- aphantasic tasia, average imagery, and hyperphantasia. Tests examining memory for ver- 1. 6 bal and visual material over intervals of half an hour did not distinguish the groups. But there were marked differences when we compared the richness of the description of personally signifi- 0.8 cant past and imagined events. This result meshes well with the accounts given by some—though not all—people with aphantasia of relatively scant autobio- ) baseline ( microseconds from SCL shift 0.0 graphical memory (see figure on page 117). 20 40 60 mean SCL Neural studies of aphantasia are also time (seconds) at an early stage. We have preliminary Adapted from M. Wicken et al., 2019. evidence that neural connectivity be- When viewing a progression of scary images, people with or without aphantasia showed a tween frontal and posterior visual re- physiological fear response, measured as a change in their skin conductance level (SCL) that gions of the brain is stronger in the rest- indicates autonomous nervous system arousal (bottom). But when read a description of a scary ing brain in people with hyperphantasia scene, only people with aphantasia lacked a physiological fear response (top).

116 American Scientist, Volume 109 © 2021 Sigma Xi, The Scientific Research Honor Society. Reproduction with permission only. Contact [email protected]. 400 seem to be essential. It seems that people 60 350 with aphantasia, especially those lacking all forms of sensory imagery, must either 50 300 use more abstract representations—such 40 250 as those of language—in their thinking 200 or unconsciously draw on imagery. We 30 need more research to tease apart these 150 20 alternatives. 100 composite score composite It has been a privilege to share so mean internal details 10 50 many insights from our participants’ inner lives. I keep a few favorites pinned 0 0 atemporal future recent remote to my board. “I’m in the dark here,” imagination task autobiographical task wrote one contributor, quoting a famous line from Scent of a Woman; another aphantasia control hyperphantasia mused, “There are lots of ways of being human,” surely one of the key messages Adapted from F. Milton et al., 2020. https://psyarxiv.com/j2zpn from this work; a third wrote poignantly, Violin plots, named for their shape, show both the range and frequency of data (thick horizontal “I’m learning to love without images.” lines show median scores). For a task in which people are asked to describe imaginary scenes, either in an imagined future (for example, next New Year’s Eve) or without any specific temporal location, the plots show the richness of the narratives produced by people with aphantasia, Bibliography hyperphantasia, and average imagery vividness (left). Differences also arise when the same Aldworth, S., and M. MacKisack, eds. 2018. groups are asked to recollect recent or remote episodes from their personal past (right). Extreme Imagination: Inside the Mind’s Eye. Exhibition Catalogue. Exeter: University of Exeter Press. Second, does aphantasia imply an aphantasia for whom this description is Bainbridge, W., Z. Pounder, A. F. Eardley, and absence of imagination? The answer is true, but for several reasons I am now C. I. Baker. 2021. Quantifying aphantasia a clear no. Among those people who doubtful that this hypothesis about through drawing: Those without visual im- contacted us because our description of aphantasia is generally applicable. For agery show deficits in object but not spatial aphantasia matched their own experi- one thing, many people with aphanta- memory. Cortex 135:159–172. ence were the prolific neurologist Oliver sia love the visual world, and some of Dawes, A. J., R. Keogh, T. Andrillon, and J. Pearson. 2020. A cognitive profile of multi- Sacks, the pioneering geneticist Craig them, aphantasic artists, devote their sensory imagery, memory, and dreaming in Venter, Pixar President Ed Catmull, and lives to depicting it. For another, about aphantasia. Scientific Reports 10:10022. Mozilla Firefox cocreator Blake Ross. 50 percent of people with extreme im- Kosslyn, S., W. Thompson, and G. Ganis. 2006. In an unexpected twist, over the past agery report that all modalities of im- The Case for Mental Imagery. New York: Ox- five years more than 100 aphantasic vi- agery, including imagery of sounds, ford University Press. sual artists have been in touch with us, are vivid in the case of hyperphantasia Laeng, B., and U. Sulutvedt. 2014. The eye pupil adjusts to imaginary light. Psychological Science 25:188–197. Pearson, J. 2019. The human imagination: The cognitive neuroscience of visual mental im- For some of us, thought is closer to agery. Nature Reviews Neuroscience 20:624–634. Wicken, M., R. Keogh, and J. Pearson. 2019. sensory experience, and for others, The critical role of mental imagery in human emotion: Insights from aphantasia. it’s more remote. bioRxiv doi:10.1101/726844 Winlove, C., et al. 2018. The neural correlates of visual imagery: A co-ordinate-based meta-analysis. Cortex 105:4–25. which has allowed my colleagues, artist or dim to absent in the case of aphan- Zeman, A. 2020. Aphantasia. In The Cambridge Susan Aldworth and cultural historian tasia. This result suggests that a more Handbook of the Imagination, A. Abraham, Matthew MacKisack, to mount an exhi- relevant distinction than verbal versus ed., pp. 692–710. Cambridge: Cambridge bition of aphantasic and hyperphantasic visual may be abstract versus experien- University Press. art. Imagination is a much richer and tial: For some of us, thought is closer to Zeman, A., et al. 2020. Phantasia: The psychological significance of lifelong visual imag- more complex capacity than visualiza- sensory experience, and for others, it’s ery vividness extremes. Cortex 130:426–440. tion. Aphantasia illustrates the wide va- more remote. But it’s possible that no Zeman, A., M. Dewar, and S. Della Sala. 2015. riety of representation available to hu- single distinction is sufficient to capture Lives without imagery: Congenital aphan- man minds and brains; visual imagery the contrast between aphantasia and tasia. Cortex 73:378–380. is by no means the only one. hyperphantasia, not least because it is Zeman, A., S. Della Sala, L. Torrens, V. Goun- Third, does aphantasia imply a ver- unlikely that either is a single entity. touna, D. McGonigle, and R. Logie. 2010. Loss of imagery phenomenology with intact visual bal cognitive style? This connection Finally, what is imagery for? Aristotle imagery performance: A case of “blind imagi- seemed likely to me when I first be- wrote, “The soul never thinks without nation.” Neuropsychologia 48:145–155. gan to think about this topic. If you a phantasm.” He was wrong; aphanta- lack a mind’s eye, I mused, presum- sia contradicts this view. That is not to Adam Zeman is a professor of cognitive and behav ably you will tend to be more interested say that imagery does not play a part in ioral neurology at the University of Exeter College in sounds and words than visual im- the thinking of those of us who have it. of Medicine and Health in the United Kingdom. ages. There may be some people with But conscious imagery, at least, does not Email: [email protected] www.americanscientist.org © 2021 Sigma Xi, The Scientific Research Honor Society. Reproduction 2021 March–April 117 with permission only. Contact [email protected].