There is broad agreement between many theories that spoken word recognition is a parallel process of competition between multiple lexical candidates. The ability to take part in this competition can be thought of as the defining characteristic of a lexical representation. Four experiments examined the effects of exposure frequency and time on the acquisition of novel spoken words, as measured by their ability to enter into lexical competition.
Participants were familiarised with a set of nonsense words that diverged from real words in the final segments (e.g., cathedruke, derived from cathedral) over the course of a week. Immediately after initial exposure, subjects showed familiarity with the form of the novel words, as tested in a two-alternative forced choice task. The effect of this exposure on lexical competition was examined by presenting the real words (e.g., cathedral) in a lexical decision test. If the novel items had developed lexical representations then the effect on the real words should have been inhibitory, due to lexical competition. In fact the immediate effect of the exposure was facilitatory, suggesting that the novel words had activated the representation of the closest real word (Experiment 1). However, over the course of the week, inhibitory lexical competition effects emerged, while familiarity effects remained largely constant (Experiment 2). Experiment 3 replicated this effect, and showed that the competition effect was restricted to word-initial rather than word-final overlap, as models of spoken word recognition would predict. Finally, Experiment 4 compared two explanations of the previous effects, one based on the number of times a novel word is encountered and the other based on the amount of time elapsed from first encounter with the novel word. The results lent support to both explanations: high frequency words (encountered 60 times in one session) generated lexical effects quickly, whereas low frequency words (encountered 12 times in one session) showed lexical effects only after a week's delay.
These findings suggest that representations of novel words transform over
time and across levels of exposure. Initially, words are encoded in a
short-term, possibly episodic, memory system, and seem to be linked to
similar items in the lexicon. If these words are encountered sufficiently
often, and/or after a sufficient amount of time, the novel items become
integrated into the mental lexicon and develop their own representations,
which are able to participate in the normal lexical competition
process.