LOOKING INWARDS: Imagination lost: In search of the elusive mind’s eye

In 2005, the  British  neurologist  saw  a  patient  who  said that a minor surgical procedure had taken  away  his  ability  to  conjure  images.  Over  the 16 years since that first patient, Dr. Zeman and  his  colleagues  have  heard  from  more  than  12,000  people  who  say  they  don’t  have  any  such  mental  camera.

The  scientists  estimate that tens of millions of people share the condition,  which  they’ve  named  aphantasia,  and millions more experience extraordinarily  strong  mental  imagery,  called  hyperphan-tasia.In their latest research, Dr. Zeman and his colleagues   are   gathering   clues   about   how   these  two  conditions  arise  through  changes  in the wiring of the brain that join the visual centers  to  other  regions.

And  they’re  beginning  to  explore  how  some  of  that  circuitry  may  conjure  other  senses,  such  as  sound,  in  the  mind.  Eventually,  that  research  might  even   make   it   possible   to   strengthen   the   mind’s eye — or ear — with magnetic pulses. “This is not a disorder as far as I can see,” said Dr. Zeman, a cognitive scientist at the University  of  Exeter  in  Britain.  “It’s  an  intriguing  variation in human experience.

” The patient who first made Dr. Zeman aware of aphantasia  was  a  retired  building  surveyor  who  lost  his mind’s eye after minor heart surgery. To protect  the  patient’s  privacy,  Dr.  Zeman  refers to him as M.X.When M.X. thought of people or objects, he did  not  see  them.  And  yet  his  visual  memories  were  intact.  M.X.  could  answer  factual  questions   such   as   whether   former   Prime   Minister  Tony  Blair  has  light-coloured  eyes.

(He  does.)  M.X.  could  even  solve  problems  that required mentally rotating shapes, even though he could not see them. In a 2015 report on  those  findings,  Dr.  Zeman  and  his  colleagues   proposed   that   those   readers   all   shared  the  same  condition,  which  the  researchers called aphantasia. To better understand  aphantasia,  Dr.  Zeman  and  his  colleagues  invited  their  correspondents  to  fill  out questionnaires.

One described the condition  as  feeling  the  shape  of  an  apple  in  the  dark.  Another  said  it  was  “thinking  only  in  radio.”  The  vast  majority  of  people  who  reported a lack of a mind’s eye had no memory of  ever  having  had  one,  suggesting  that  they  had been born without it. Yet, like M.X., they had  little  trouble  recalling  things  they  had  seen. When asked whether grass or pine tree needles are a darker shade of green, for example, they correctly answered that the needles are. On the other hand, people with aphantasia don’t do as well as others at remembering details of their own lives.

It’s possible that re-calling our own experiences — known as episodic memory — depends more on the mind’s eye  than  does  remembering  facts  about  the  world.  To  their  surprise,  Dr.  Zeman  and  his  colleagues were also contacted by people who seemed  to  be  the  opposite  of  M.X.:  They  had  intensely  strong  visions,  a  condition  the  scientists named hyperphantasia.The strength of the mind’s eye may exert a subtle  influence  over  the  course  of  people’s  lives.  Dr.  Zeman’s  questionnaires  revealed  that people with aphantasia were more likely than  average  to  have  a  job  that  involved  science or math. The genome pioneer Craig Venter even asserted that aphantasia had helped him as a scientist by eliminating distractions.