The production and comprehension lexicons: What is shared and what is not

One of the long-standing questions in psycholinguistics has been the relationship between comprehension and production. Theories of language production and comprehension typically propose that word retrieval involves the selection of at least two levels of lexical information, semantic representations and word-forms (phonological and orthographic representations). The results from five experiments tested whether semantic and word-form representations are shared between production and comprehension or separate. The experiments used a variation of the standard priming task, with word-pairs as the primes and pictures as the probes. The same probe pictures were used in all of the experiments. The word-pair trials consisted of one word which was produced and the other ignored. The logic was that produced words were both comprehended and produced, but ignored words were only comprehended. If lexical representations are shared, then both produced and ignored related primes should result in priming of the pictures on the probe trials. Experiment 1 demonstrated repetition priming for both produced and ignored primes, demonstrating that the ignored primes were processed. Experiments 2 and 3 demonstrated that taxonomically related primes slowed probe picture naming for both produced and ignored primes, supporting a model in which semantic representations are shared by production and comprehension. Experiments 4 and 5 used phonologically related primes and demonstrated that produced primes slowed picture naming but ignored primes did not. These results support a model in which the word-forms retrieved by ignored primes are represented separately from the word-forms retrieved for naming the probe pictures.