Saturday, August 20, 2016

Are there differences in people's ability to form mental images?




This is post no.3 on mental imagery.  Post no. 1 is here

In 2005, a 65 year old retired building inspector approached neurologist Adam Zerman with the complaint that following coronary angioplasty he no longer could form mental images.  Dr. Zeman could not find any description of such a phenomenon in the literature.  He tested this man with a series of tests.  Apparently, this man had good memory for his age, and good performance in a variety of cognitive tests.  The only problem he had was his inability to form mental images.
 
Dr Zeman and his team showed the man pictures of well known people and asked him to identify them.  He did that easily and when doing so, he had activation in the same brain areas that are activated during visual processing in most people.  But when he read names of known people and was asked to form a visual image of their faces, he said he couldn't do it.  The areas in the brain that are usually activated during visual imagery were not activated in his brain during this task.

Thus, beyond the subjective report of that man about his loss of the ability to form mental images, researchers saw that brain areas normally activated during the formation of mental images were not activated in his brain.  Nevertheless, he was able to perform tasks that allegedly require the formation of mental images.  He could state the color of the eyes of a well known person.  He could say which letters in English have downward "tails" (like the letters "g" or "j").  Apparently, he performed these tasks in a different way, without mental imagery. 

Journalist Carl Zimmer wrote about this research in the New York Times in 2015.  Following his article, people approached Dr.  Zeman and reported having the same phenomenon (without the coronary angioplasty).  Some of these people discovered for the first time that they were different in this respect from most people.
 
Blake Ross, a writer and programmer, a former Director of Product at Facebook, and the cofounder of Firefox,  wrote this in his facebook page: 

"If you tell me to imagine a beach, I ruminate on the “concept” of a beach. I know there’s sand. I know there’s water. I know there’s a sun, maybe a lifeguard. I know facts about beaches. I know a beach when I see it, and I can do verbal gymnastics with the word itself."
"But I cannot flash to beaches I’ve visited. I have no visual, audio, emotional or otherwise sensory experience. I have no capacity to create any kind of mental image of a beach, whether I close my eyes or open them, whether I’m reading the word in a book or concentrating on the idea for hours at a time—or whether I’m standing on the beach itself".
  
Ross writes that he does not usually remember dreams, and when he does, there is no visual or sensory component to them.  He has difficulties navigating directions.  When he reads a book, he skips the descriptions.  He has trouble remembering events from his own past (retrieving episodes from his episodic memory).
Apparently, people who cannot form mental images (a condition named APHANTASIA) are at one end of a spectrum.  Galton, the great 19th century scholar, who was one of the founding fathers of the study of intelligence, noticed the existence of individual differences in the ability to form mental images.  Contemporary researchers argue these differences encompass three aspects:
 1) Imagery Vividness. Mental Imagery vividness relates to the clarity of the mental images evoked by an individual   or the liveliness and similarity to the actual percept.

2) Imagery Control. This is the extent to which one can manipulate, transform, and hold images in mind at will.  Imagery control is the individual’s ability to self-generate a mental image or to perform certain manipulations, such as mental rotation.

2) Imagery Processing Style. Some people form detailed images of objects.  Others tend to form images of relations between objects in space (for example, a mental map).  People who tend to form object images tend to form relatively static mental pictures, which are detailed and highly vivid.  People who tend to create images of relations between objects in space tend to form dynamic images.

These differences (in the general ability to form mental images and in these three aspects) are usually measured with questionnaires, like the ones in this paper.

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What are the possible implications of this to the functioning of a child in school? To be discussed in the next post.

Zeman, A. Z., Della Sala, S., Torrens, L. A., Gountouna, V. E., McGonigle, D. J., & Logie, R. H. (2010). Loss of imagery phenomenology with intact visuo-spatial task performance: a case of 'blind imagination'. Neuropsychologia, 48, 145-155. 
 
D’Argembeau, A., & Van der Linden, M. (2006). Individual differences in the phenomenology of mental time travel: The effect of vivid visual imagery and emotion regulation strategies. Consciousness and cognition, 15(2), 342-350.  

Woojin Lee, Ulrike Gretzel.  Individual Differences in Mental Imagery Ability: Implications for Online Media Consumption.   




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