Memorizer was the first rank of the mentat training program. The final test involved absorbing a series of 2 x 104 numbers or letters and reproducing them in correct sequence, duplicating the same timing or spacing as the original. The fully prepared Memorizer was capable of retaining both related and unrelated information.
Memorizers were able to repeat entire books from recall or replicate spatial configurations, such as the layout of a city after having seen the place (or plans of it) only once, and even repeat conversations word for word from start to finish, mimicking the cadence and vocal inflection of each participant.
CHOAM directors especially appreciated the record-keeping ability of Memorizers, since the Butlerian Jihad had destroyed the most efficient means of storing the voluminous records of interplanetary commerce, but they were not exploited commercially because Gilbertus Albans insisted that the minimum rank required before a Mentat could be sold (even for routine CHOAM use), was that of Hypothesist, even in the hardest, poorest early years. He insisted that "a public representative of our Order must be able to do more than just sponge up data, chew on it, and blat it out in unhelpful chunks "'
Albans also worked hardest to help young Memorizers avoid what he called the "Babble Problem"-becoming overwhelmed by the minutiae of data. The best defense against Babble was farther training to categorize the data.