Age of acquisition effects on word generation

An early demonstration of the impact of when words were learned was found by Loftus and Suppes (1972). They showed that children's vocabulary had a significant effect on adult word generation times. However their stimuli were not explicitly rated for age of acquisition (AoA). Two experiments in the current study used an adaptation of their methodology but made use of explicit AoA ratings and implemented a matched list design. Stimuli consisted of a category followed by an initial letter of a category member, e.g., Vegetable: C. In the first experiment two groups of early and late acquired words were selected. These groups were balanced on all of the relevant independent variables. Results showed that the earlier acquired target words were produced significantly faster than the later acquired target words. In the second experiment two groups of high and low frequency words were selected. These groups were balanced for AoA and on other relevant variables. There was no significant effect of frequency on word generation tasks. A third experiment employed a delayed word naming task, to eliminate any confounding effects of the initial phoneme onset of the stimuli used.