Learning new meanings for known words: Perturbation of original meanings and retention of new meanings.

Learning a new, unrelated meaning for a known word faces competition from the word's original meaning. Moreover, the connection of the word with its original meaning also shows a subtle form of interference, a perturbation, when tested immediately after learning. However, the long-term effects of both types of interference are unclear. The present study paired both high and low frequency words with new unrelated meanings, testing the fate of new and original meanings on three different days over one week as a function of word familiarity. The results were that learners maintained memory for new meanings of high frequency words better than the new meanings of low frequency words over one week. Following learning, meaning decisions on high frequency words that required the original meaning of the trained word were delayed relative to decisions on control words - but only when testing was immediate and the stimulus-onset asynchrony (SOA) between the trained word and its original meaning probe was 200 ms. When the SOA was 500 ms or when the test was delayed by one day or one week, no effect occurred. The findings indicate that in the learning of new meanings for known words, word familiarity benefits long-term retention of new meanings. The facilitation effect occurs along with a perturbation effect, in which the original meaning of a familiar word is made momentarily less accessible immediately after learning.