Abstract: Mental lexicon is the representation of lexical knowledge in human mind. One way to explore the organization of the mental lexicon is the use of word associations. After reviewing the paradigmatic/syntagmatic dichotomy in the classification of response words from word association tests, the authors point out that it is problematic for researchers to merely rely on their own intuition in classifying response words, which is common practice among word association researchers. The authors then suggest the possibility of applying WordNet and BNC into identifying paradigmatic and syntagmatic responses respectively and discuss such a possibility in detail.