Short‐term Memory and the Limited Capacity Hypothesis

Murdock has shown that the immediate free recall of a list of words is adversely affected by a concurrent card‐sorting task, with degree of impairment increasing with the number of sorting alternatives. He interprets this in terms of a limited capacity STM mechanism. The present study repeats Murdock's study with the addition of an STM control, a condition in which recall was delayed for 30 sec. by a rehearsal‐preventing task. Card‐sorting load influenced the long‐term component (measured by delayed recall), but not the short‐term component (measured by subtracting delayed from immediate recall). It is suggested that the limited capacity system affects input into LTM rather than STM.