In this study we present the results of a lexical decision experiment where the variables manipulated are Base frequency and Affix productivity. The results show significant main effects for both variables for the first time in Spanish, as well as for the interaction between the two. However, pair analysis shows that the Base Frequency effect is not significant when the Affix Productivity is low, while the Affix Productivity effect is produced regardless of the Base Frequency. The results for the main effects show a morphological representation in the lexicon, whilst the results of pair comparisons suggest a different representation of stems and affixes in the lexicon. These results support the idea that complex words incorporating unproductive affixes are processed differently from words incorporating productive affixes. The results are finally explained in terms of a hierarchical model of morphological processing.
