Hi There!

Skittish is incorrect for the first blank.

The art of memory often resulted in amazing displays of (i)_____ data, from the recall of long complicated word sequences to the recital of epic poems such as The Odyssey. The apparatuses of memory that developed were referred to as 'the artificial memory', distinct from its opposite, the (ii)_____ and less regulated 'natural memory'. These categories are akin to Marcel Proust's notions of voluntary and involuntary memory, with the difference that Proust found authenticity in 'the natural' or involuntary memory rather than in the more (iii)_____ recall of the automatic or voluntary memory.


Reading the sentence carefully will easily lead you to find obvious clue. Refer the above highlighted part for the clues.

First blank: The author talks about recalling data and reciting old poems and the only word similar to this part is recollected, skittish means nervous, excitable or easily scared. And this is completely tangential to the point of discussion. Even if you don't find a clue refer the context it might atleast give you some help to negate the completely wrong answer.
Recollected

Second Blank: Then the author talks about artificial memory and says is opposite i.e. natural memory and describes it as less regulated and the word that is similar is untutored. Studied is not supported by the context and is 180 opposite similarly for imposing.
Untutored

Third blank: Lastly, the author says the these categories are akin i.e. similar to MP's notions and describes the difference between authenticity in natural and artificial memory. Using the previous sentence we know natural memory is untutored thus, artificial memory is more tutored i.e. organized.
Organized


IMO A E I

Hope this helps!