Answer:
sensory memory, short term memory.
Step-by-step explanation:
Sensory memory is when you see something or an infomation, and after that thing is taken away you can still process, store and remember that thing in your memory. Sensory memory are of two kinds and they are; sound sensory memory and visual sensory memory.
Short term memory is the memory that contains information for a short time, it can be a memory or information you are currently thinking which can be for few seconds.
I won't be able to identify all the letters presented on the screen because i need enough time to transfer the letter information from sensory memory to short term memory (because I need the letters right now and not something I need to remember later).