Roles of Semantic Similarity and Category Size on Semantic Effect in Picture-Word Interference Paradigm

Abstract

One of the workhorses in studying spoken word production is the picture-word interference paradigm (PWI). In this paradigm, speakers are instructed to ignore superimposed written distractor words while fulfilling the picture-naming task. An essential finding in picture - word interference paradigm is that people spend more time in naming pictures when distractor word is of the same category as the picture naming (semantic related word) than when the distractor is unrelated. That effect is often referred to as semantic interference effect (SIE). A reversed finding is that pictures naming latency is shorter in condition of related words than in condition of unrelated words. That effect is referred to as semantic facilitation At present, there are several theories about the nature and level of effects in picture - word interference paradigm. Lexical selection by competition hypothesis assumes that SIE is the result of competition between the representations of related distractor word and the target word and then arises at lexical level. Conceptual selection model interprets the effects as the result of competition between the representations of distractor conception and the target conception. As a result, effect should arise at level. Response selection account proposes that there is a single-channel output buffer in word production and the non –target response would occupy the buffer earlier than the target. It will take some time to exclude the non-target response from the buffer and induces SIE. So SIE arises at the post-lexical stage in word production. Each account has its experimental evidence and each has its difficulty in explaining some phenomenon. In the present study, 2 experiments were conducted to investigate the universality of current theories and to explore the roles of similarity and category size on effect in PWI. In Experiment 1, subjects were asked to name pictures accompanied by words with high similarity or words with low similarity at either basic level or at category level. Results showed a shorter picture - naming latency in condition of high similarity distractor words than in condition of low similarity words, leading to significant similarity effect. Nevertheless, similarity effect occurred in basic - level naming rather than in category - level naming and the effect was stronger for low familiar pictures than for high familiar ones. Experiment 1 also showed that latency of category - level naming was shorter than that of basic-level naming and high familiar pictures were named faster than low familiar ones. Combining previous studies, these results suggested that the intensity of relationship between pictures and words would affect the direction of effect in the PWI. Semantic facilitation effect will be foundwhen there is strong relationship between pictures and words. Otherwise, interference will be found. In Experiment 2, subjects were asked to name pictures accompanied by related words or by unrelated words. Thirty pictures from large size of category and another thirty pictures from small size of category were chosen for this experiment. Results showed that related words had rather different influences on pictures naming in different condition. They would promote pictures category-level naming, thus giving rise to facilitation effect. However, they would interference pictures basic-level naming, thus causing interference effect. Category size had a prominent influence on these effects. Semantic interference effect would be stronger for large size of category pictures in basic-level naming and facilitation effect also would be stronger for big size of category pictures in category-level naming. Combining previous studies, the experiment suggested that the range of relationship between pictures and words affects the size of effect. When there is wide range of relationship, the effect will became stronger. Otherwise, the effect will be weaker. Single current theory of effect couldn’t give a proper explanation for the findings in this study. Results in this study were discussed with reference to the equilibrium between conceptual priming and lexical competition. If the conceptual priming overweight the lexical competition, facilitation effect would be found, otherwise interference would be found.