When you hear the word “apple”, do you picture a Red Delicious apple or a green Granny Smith? Or neither, because you can't conjure up a visual image of an apple (or of anything else, for that matter)?
Aphantasia is the inability to generate visual images, which can be a congenital condition or acquired after brain injury (Farah, 1984). The most striking aspect of this variation in mental life is that those of us with imagery assume that everyone else has it, while those without are flabbergasted when they learn that other people can “see” pictures in their head.
Programming prodigy Blake Ross created a sensation recently with his eloquent essay on what's it's like to discover that all your friends aren't speaking metaphorically when they say, “I see a beach with waves and sand.”
Aphantasia: How It Feels To Be Blind In Your Mind
I just learned something about you and it is blowing my goddamned mind.
. . .
Here it is: You can visualize things in your mind.
If I tell you to imagine a beach, you can picture the golden sand and turquoise waves. If I ask for a red triangle, your mind gets to drawing. And mom’s face? Of course.
. . .
I don’t. I have never visualized anything in my entire life. I can’t “see” my father’s face or a bouncing blue ball, my childhood bedroom or the run I went on ten minutes ago. I thought “counting sheep” was a metaphor. I’m 30 years old and I never knew a human could do any of this. And it is blowing my goddamned mind.
It's worth reading Ross's account in its entirety to gain insight into the vast individual variation in our internal mental lives.
Although the term aphantasia is new (coined by Zeman et al., 2015), the condition isn't; Francis Galton published a paper on the Statistics of Mental Imagery in 1880. Similar to Ross, many of Galton's s friends (male scientists) were shocked to learn that others had imagery:1
To my astonishment, I found that the great majority of the men of science to whom I first applied, protested that mental imagery was unknown to them, and they looked on me as fanciful and fantastic in supposing that the words 'mental imagery' really expressed what I believed everybody supposed them to mean. They had no more notion of its true nature than a colour-blind man who has not discerned his defect has of the nature of colour. They had a mental deficiency of which they were unaware, and naturally enough supposed that those who were normally endowed, were romancing.
The nature of mental images has been a topic of philosophical debate in cognitive science since the 1970s. Are mental images quasi-perceptual representations that activate visual areas of the brain (Kosslyn and colleagues), or non-pictorial, abstract, symbolic descriptions (Zenon Pylyshyn)? The Stanford Encyclopedia of Philosophy's entry on Mental Imagery provides an indispensable background on the philosophical, theoretical, and empirical debates in the field. As well, extensive research on individual differences in mental imagery (e.g., Kosslyn et al., 1984) can inform new studies on aphantasics.
Aphantasia and Paivio's Dual Coding Theory
To investigate the role of imagery in verbal memory, I propose a return to classic cognitive psychology experiments of the 1970s. Alan Paivio's Dual Coding Theory specifies two types of mental representations, or codes, for words and mental images (Paivio, 1971). The verbal code and imagery code are both activated by pictures, which can account for the picture superiority effect: pictures are better remembered than their verbal referents (i.e., words). The picture superiority effect should be abolished in those who cannot generate visual images.2
Even more interestingly, words that are highly imageable (concrete nouns like elephant) are better remembered than words that are rated low in imageability (abstract nouns like criterion). The original ratings from 1968 and the expanded 2004 version (concreteness, imageability, meaningfulness, familiarity) are available online: Clark and Paivio (2004) Norms. Lists of high and low imageable nouns that are carefully matched on other lexical factors (e.g., number of letters, word frequency, complexity) can be presented in a memory test. The recognition memory (or free recall) advantage for concrete, highly imageable words should be diminished or abolished in relation to self-reported imagery abilities.
I believe this experiment would address the objection of psychogenic aphantasia (“refusing to imagine”), because the concreteness advantage (using imagery during encoding) could not be mobilized as an explicit (or perhaps implicit) strategy. Given the hundreds (if not thousands) of Aphantasics who have made blog comments, joined Facebook groups and other communities, taken surveys, and of course contacted Dr. Zeman, the sample size might be quite respectable.
Quick poll (please RT!): Can you draw up an image in your mind's eye...?— Kevin Mitchell (@WiringTheBrain) May 3, 2016
Mental images poll. Is 'mental image' a misnomer? Pls RT, this stuff is weird. (CC: @WiringTheBrain; @blakeross).— Ed Berry (@ed_berry) May 3, 2016
1 Aphantasia seems bizarrely overrepresented in Galton's cronies. Here's his explanation:
My own conclusion is, that an over-readiness to perceive clear mental pictures is antagonistic to the acquirement of habits of highly generalised and abstract thought, and that if the faculty of producing them was ever possessed by men who think hard, it is very apt to be lost by disuse. The highest minds are probably those in which it is not lost, but subordinated, and is ready for use on suitable occasions.2 Of note here, some with aphantasia report severe deficits in autobiographical memory.
ADDENDUM (May 16 2016): see this website on Severely Deficient Autobiographical Memory (SDAM) - research conducted by Dr. Brian Levine.
Farah MJ. (1984). The neurological basis of mental imagery: A componential analysis. Cognition 18:245-72.
GALTON, F. (1880). I.--STATISTICS OF MENTAL IMAGERY Mind, os-V (19), 301-318 DOI: 10.1093/mind/os-V.19.301
Kosslyn SM, Brunn J, Cave KR, Wallach RW. (1984). Individual differences in mental imagery ability: a computational analysis. Cognition 18:195-243.
Paivio A. (1969). Mental imagery in associative learning and memory. Psychological Review 76: 241-263.
Paivio A. (1971, 2013). Imagery and verbal processes. Holt, Rinehart & Winston / Psychology Press.
Zeman, A., Dewar, M., & Della Sala, S. (2015). Lives without imagery – Congenital aphantasia Cortex, 73, 378-380 DOI: 10.1016/j.cortex.2015.05.019
ADDENDUM (May 7 2016): via @vaughanbell, a new review article by the University of Exeter group (part of their project, The Eye's Mind):
MacKisack M, Aldworth S, Macpherson F, Onians J, Winlove C, Zeman A. (2016). On Picturing a Candle: The Prehistory of Imagery Science. Front Psychol. 7:515.
Not only Galton, Paivio, Kosslyn, and Pylyshyn but also Aristotle, Plato, Thomas Aquinas, and more.
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