Proactive Interference in Short-Term Memory as a Function of Prior-Item Retention Interval

The experiment was conducted to examine the effect of prior-item retention interval on the retention of a given item in a short-term memory test series. There were five conditions. The retention interval for the fifth test of five successive tests was 15 sec. for all five conditions. The retention intervals for tests 1–4 were constant for a condition but varied across conditions. These retention intervals were 5, 10, 15, 20 and 25 sec. Five consonant trigrams constructed from the set of letters sharing the vowel sound “e” were used for all conditions. Recall on test 5 was a direct function of prior-item retention interval. The data indicate, therefore, that the availability of prior items for proactive interference is an inverse function of prior-item retention interval.