echoic

Meaning: Echoic memory is the auditory form of sensory memory, the first stage in the information-processing model of memory. It holds a large amount of sound in unprocessed form for a few seconds, typically cited as about 3–4 seconds. This is why you can often "replay" the last sentence someone said even when you were not listening. If the information is attended to, it passes into short-term (working) memory, where it can be rehearsed and encoded. If it is not attended to, the trace fades.

On the MCAT: Expect questions that match memory stage to sense and duration. Iconic memory is visual and lasts a fraction of a second. Echoic memory is auditory and lasts a few seconds. Short-term memory lasts longer, roughly tens of seconds without rehearsal, and has a limited capacity of about seven items, give or take two. A passage may describe a listening task, such as dichotic listening or shadowing, and ask why an unattended message can be recalled briefly or why attention decides what gets stored. Sperling's partial-report experiment is the classic study of iconic memory, so do not link it to echoic memory.

Common confusion: Students swap iconic and echoic, or treat echoic memory as short-term memory. Echoic memory is a sensory register. It is tied to one sense, it is very brief, and it does not depend on rehearsal. Sound that is not attended to is lost from it quickly.