Lives without imagery - Aphantasia PDF

c o r t e x 7 3 ( 2 0 1 5 ) 3 7 8 e3 8 0 Available online at www.sciencedirect.com ScienceDirect Journal homepage: www.elsevier.com/locate/cortex Letter...

c o r t e x 7 3 ( 2 0 1 5 ) 3 7 8 e3 8 0 Available online at www.sciencedirect.com ScienceDirect Journal homepage: www.elsevier.com/locate/cortex Letter to the Editor Lives without imagery e Congenital aphantasia Adam Zeman a,*, Michaela Dewar b and Sergio Della Sala c a University of Exeter Medical School, College House, St Luke's Campus, Exeter, UK b Department of Psychology, School of Life Sciences, Heriot-Watt University, Edinburgh, UK c Human Cognitive Neuroscience, University of Edinburgh, Edinburgh, UK article info agnosia and imagery loss, and ii) ‘imagery generation’ deficits selectively disabling imagery (Farah, 1984). Article history: In 2010 we reported a particularly ‘pure’ case of imagery Received 3 March 2015 generation disorder, in a 65 year old man who became unable Reviewed 5 May 2015 to summon images to the mind's eye after coronary angio- Revised 18 May 2015 plasty (Zeman et al., 2010). Following a popular description of Accepted 20 May 2015 our paper (Zimmer, 2010), we were contacted by over twenty Published online 3 June 2015 individuals who recognised themselves in the article's ac- count of ‘blind imagination’, with the important difference that their imagery impairment had been lifelong. Here we blue highlight -- person describe the features of their condition, elicited by a ques- yellow -- important tionnaire, and suggest a name e aphantasia e for this poorly green -- detail recognised phenomenon. pink -- interesting 1. Introduction 2. Results Visual imagery is, for most of us, a conspicuous ingredient of everyday experience, playing a prominent role in memory, 21 individuals contacted us because of their lifelong reduction daydreaming and creativity. Galton, who pioneered the of visual imagery. We explored the features of their condition quantitative study of visual imagery with his famous ‘break- with a questionnaire devised for the purpose and the Vivid- fast-table survey’, reported a wide variation in its subjective ness of Visual Imagery Questionnaire (VVIQ) (Marks, 1973) (see vividness (Galton, 1880). Indeed, some participants described Supplementary Material for further details). Participants ‘no power of visualising’. This phenomenon has received little typically became aware of their condition in their teens or attention since, though Faw reported that 2.1e2.7% of 2,500 twenties when, through conversation or reading, they realised participants ‘claim no visual imagination’ (Faw, 2009). that most people who ‘saw things in the mind's eye’, unlike The experience of voluntary imagery is associated with our participants, enjoyed a quasi-visual experience. 19/21 activity in fronto-parietal ‘executive’ systems and in posterior were male. 5/21 reported affected relatives. 10/21 told us that brain regions which together enable us to generate images on all modalities of imagery were affected. Our participants rat- the basis of our stored knowledge of appearances ing of imagery vividness was significantly lower than that of (Bartolomeo, 2008). The relative contributions of lower and 121 controls (p <.001, Mann Whitney U test e see Fig. 1). higher order visual regions to the experience of visual imagery Despite their substantial (9/21) or complete (12/21) deficit in are debated (Bartolomeo, 2008). Clinical reports suggest the voluntary visual imagery, as judged by the VVIQ, the majority existence of two major types of neurogenic visual imagery of participants described involuntary imagery. This could impairment: i) visual memory disorders, causing both visual occur during wakefulness, usually in the form of ‘flashes’ (10/ * Corresponding author. University of Exeter Medical School, College House, St Luke's Campus, Exeter EX1 2LU, UK. E-mail addresses: [email protected] (A. Zeman), [email protected] (M. Dewar), [email protected] (S. Della Sala). http://dx.doi.org/10.1016/j.cortex.2015.05.019 0010-9452/© 2015 Elsevier Ltd. All rights reserved.  c o r t e x 7 3 ( 2 0 1 5 ) 3 7 8 e3 8 0 379 prosopagnosia is associated with unusually low (Gruter et al., 2009), and synaesthesia with unusually high (Barnett & Newell, 2008), VVIQ scores. The participants described here were self-selected and some of our findings, such as the male predominance, may reflect the readership of a science magazine like Discover. There is a need, therefore, for further study in a more repre- sentative sample. The existence of lifelong ‘aphantasia’ raises numerous additional questions. How commonly does congenital aphantasia occur? Existing data suggest a fre- quency of around 2% but there is no fully reported large scale study. The evidence of familial occurrence should be investi- gated further. Does congenital aphantasia have objective neuropsychological associations? Correlations between im- agery vividness and cognitive functioning have been elusive in the past, but recently developed measures of autobiographical memory (Levine, Svoboda, Hay, Winocur, & Moscovitch, 2002), imaginative thinking and ‘visual-object intelligence’ Fig. 1 e Distribution of Vividness of Visual Imagery (Blazhenkova & Kozhevnikov, 2010) open up new avenues for Questionnaire (VVIQ) scores in participants with exploration. Personality and mood may also be relevant vari- aphantasia and control participants (VVIQ range extends ables. Are there subtypes of congenital aphantasia? The de- from 16, lowest imagery score to 80, highest imagery scriptions given by our participants suggest that in some cases score). visual memory is preserved even if visual imagery is absent, while others may rely entirely on non-visual representations 21) and/or during dreams (17/21). Within a group of partici- in memory tasks; the relationship between aphantasia and pants who reported no imagery while completing the VVIQ, congenital prosopagnosia also deserves further study. If, as 10/11 reported involuntary imagery during wakefulness and/ we hypothesise, the absence or reduction of visual imagery or dreams, confirming a significant dissociation between has neural correlates, can we discover these? We are opti- voluntary and involuntary imagery (p <.01, McNemar Test). mistic that modern structural and functional brain imaging Participants described a varied but modest effect on mood and may help to answer questions about the nature of visual im- relationships. 14/21 participants reported difficulties with agery that were first posed in ancient Greece and first quan- autobiographical memory. The same number identified tified at Sir Francis Galton's breakfast table over a hundred compensatory strengths in verbal, mathematical and logical years ago. domains. Their successful performance in a task that would normally elicit imagery e ‘count how many windows there are in your house or apartment’ e was achieved by drawing on what participants described as ‘knowledge’, ‘memory’ and Supplementary data ‘subvisual’ models. Supplementary data related to this article can be found at http://dx.doi.org/10.1016/j.cortex.2015.05.019. 3. Discussion 4antası́a, phantasia, is the classical Greek term for imagina- references tion, defined by Aristotle as the ‘faculty/power by which a phantasma [image or mental representation] is presented to us’ (Aristotle, translated Hamlyn, 1968). We propose the use of Aristotle. (1968). De Anima. Books II and III (with certain passages the term ‘aphantasia’ to refer to a condition of reduced or from Book I) [Hamlyn, D.W., Trans.]. Oxford: Clarendon Press. absent voluntary imagery. Terms used previously in related Barnett, K. J., & Newell, F. N. (2008). Synaesthesia is associated with enhanced, self-rated visual imagery. Consciousness and contexts include ‘defective revisualisation’ (Botez, Olivier, Cognition, 17, 1032e1039. Vezina, Botez, & Kaufman, 1985) and ‘visual irreminiscence’ Bartolomeo, P. (2008). The neural correlates of visual mental (Nielsen, 1946). imagery: an ongoing debate. Cortex, 44, 107e108. Sceptics could claim that aphantasia is itself a mere fan- Blazhenkova, O., & Kozhevnikov, M. (2010). Visual-object ability: a tasy: describing our inner lives is difficult and undoubtedly new dimension of non-verbal intelligence. Cognition, 117, liable to error (Hurlburt & Schwitzgebel, 2007). We suspect, 276e301. Botez, M. I., Olivier, M., Vezina, J. L., Botez, T., & Kaufman, B. however, that aphantasia will prove to be a variant of neuro- (1985). Defective revisualization: dissociation between psychological functioning akin to synaesthesia (Barnett & cognitive and imagistic thought case report and short review Newell, 2008) and to congenital prosopagnosia (Gruter, of the literature. Cortex, 21, 375e389. Gruter, Bell, & Carbon, 2009). Indeed, aphantasia may have Farah, M. J. (1984). The neurological basis of mental imagery: a some specific relationship to these disorders, as congenital componential analysis. Cognition, 18, 245e272. 380 c o r t e x 7 3 ( 2 0 1 5 ) 3 7 8 e3 8 0 Faw, B. (2009). Conflicting intuitions may be based on differing episodic from semantic retrieval. Psychology and Aging, 17, abilities - evidence from mental imaging research. Journal of 677e689. Consciousness Studies, 16, 45e68. Marks, D. F. (1973). Visual imagery differences in the recall of Galton, F. (1880). Statistics of mental imagery. Mind, 5, 301e318. pictures. British Journal of Psychology, 64, 17e24. Gruter, T., Gruter, M., Bell, V., & Carbon, C. C. (2009). Visual mental Nielsen, J. (1946). Agnosia, apraxia, aphasia: Their value in cerebral imagery in congenital prosopagnosia. Neuroscience Letters, 453, localisation (2nd ed.). New York: Hoeber. 135e140. Zeman, A. Z., Della Sala, S., Torrens, L. A., Gountouna, V. E., Hurlburt, R. T., & Schwitzgebel, E. (2007). Describing inner McGonigle, D. J., & Logie, R. H. (2010). Loss of imagery experience: Proponent meets sceptic. Cambridge, Massachusetts: phenomenology with intact visuo-spatial task performance: a MIT Press. case of 'blind imagination'. Neuropsychologia, 48, 145e155. Levine, B., Svoboda, E., Hay, J. F., Winocur, G., & Moscovitch, M. Zimmer, C. (2010). The brain: Look deep into the mind's eye. Discover, (2002). Aging and autobiographical memory: dissociating March Issue (pp. 28e29).