Level of categorisation effect: A novel effect in the picture-word interference paradigm

In four experiments we explored the effects of two variables in the picture-word interference paradigm: semantic relatedness and the level of categorisation of distractors relative to pictures' names. Experiment 1 addressed whether the contrasting effects of semantically related distractors in category- and basic-level naming have a methodological origin (i.e., differences in the number of responses and the number of repetitions of responses between experiments). Experiments 2, 3 and 4 explored the effect of the level of categorisation of distractor words relative to the level of categorisation of the response, independent of semantic relatedness. Two main results are reported. First, the effect of semantically related distractors depends on the level of categorisation at which the response has to be given. Second, semantically unrelated distractors at the same level of categorisation as that of the response interfere more than unrelated distractors at a different level of categorisation. The implications of these results for the interpretation of picture-word interference effects and their implications for models of lexical access in speech production are discussed.