This is when someone experiences detailed mental images. Nikola Tesla was a genius, as he had photographic memory. He spoke eight languages, including: Serbian, English, Czech, German, French, Hungarian, Italian, and Latin. He could memorize entire books and recite them at will. He could visualize devices entirely in his head and then build then without ever writing anything down. He suffered from a peculiar affliction in which blinding flashes of light would appear from his eyes, often accompanied by visions.

He developed forms of obsessive compulsive disorders: a hatred for jewelry, and round object could not touch hair, did not like to shake hands, became obsessed with the number 3 and cleanliness, and if he read one of an author's books, he felt compelled to read all of their books.

Finally he lived to be 86 and was celibate his entire life, he claimed that his chastity was very helpful to his scientific abilities.