Can’t form a mental image? No big deal.

UPDATE (23/6/15) - Carl Zimmer followed up his Discover piece with an NYT article about a recent paper in Cortex naming this non-imaging 'aphantasia'. The lead researcher is Dr Adam Zeman and he's interested to hear from people who experience this; his email is a.zeman@exeter.ac.uk (tell him we sent you :)

Discover covers a really cool Neuropsychologia article about a man, MX, who lost his ability to experience mental imagery.

Mental imagery is a divisive topic in psychology. Some (most notably Kosslyn) argue that mental images are essential to many types of cognition. According to this camp, mental images are functionally similar (but not identical to) like-modality perception (Kosslyn, 2004 summarises this view nicely). Imagining an apple and seeing an apple involve similar mechanisms. Furthermore, I can use my mental image of an apple to answer questions about its properties – is it red? is it heavier than a plum? But, many other people argue that, although we might feel like we’re using pictures in our imagination to solve various problems, the real work is done by non-depictive representations (see Pylyshyn, 2003 for a good review). When we’re asked to answer questions about an apple’s properties, we can think about what it would be like to see the apple, but this doesn’t entail that the representation is depictive, in this case, pictorial.