Date of Award

Spring 1984

Project Type


Program or Major


Degree Name

Doctor of Philosophy


Four auditory lexical decision experiments were run to assess the effects of word frequency, word length, and word repetition. Experiment I examined the effects of word length, word frequency, and stimulus repetition on RT. The results demonstrated a significant main effect for length and frequency and a significant length by frequency interaction. Long words showed the greatest frequency effect. There was no significant repetition effect. In this experiment the repeated stimuli were separated by at least seven minutes. Experiment II examined the effect of stimulus repetition with the repeated stimuli separated by 0-15 stimuli. This experiment demonstrated a significant repetition effect, but no frequency effect. Experiment III treated word length as a continuous variable and word frequency as a dichotomized variable. Here it was demonstrated that word length accounted for 10% of the variability. Word frequency accounted for 4.6% of the variance of polysyllables and 6% of the variance of monosyllables. Further, it was found that there was a frequency effect only for monosyllables under 500 msec long. Experiment IV treated word length and word frequency both as continuous variables. Word length accounted for 9% of the variance in this Experiment. Word frequency accounted for 3.4% of the variance of polysyllables and 4.8% of the monosyllables under 500 msec. Finally, Experiments I, II, and IV included the subject's verbal ability as a predictor of RT. In all three experiments verbal ability was negatively correlated to false positive responses. In Experiment I only, subjects with high verbal ability scores responded faster to stimuli than subjects with low verbal ability scores (mean difference = 158 msec).