ROC Modelling Data of the Word Frequency Effect: A Formal Model of Visual Word Recognition

Abstract

This article presents a formal statistical model for assessing the word frequency effect in recognition memory. This topic is relevant because word frequency is the best predictor of performance in recognition memory tasks. Signal Detection Theory was applied using high-frequency and low-frequency words as item-signals. Signal Detection Theory test assumes orthogonality of responses: hits, false alarms, correct rejections, and incorrect rejections. Ninety-six adult male and female students participated in two experiments: one conducted in the laboratory and the other in the class-room. The selected words for memory contained 3 to 5 letters and 1 or 2 syllables to control for length. Significant differences were found between high-frequency and low-frequency words in the number of false alarms for the two experiments. The differences were statistically significant in two experiments. The Cohen effect size was 0.6 and 0.45 respectively. The word frequency effect in first- and second-experiments was F (1, 46) = 4.13, MCE. = 2.34, p = 0.003 and F (1, 46) = 3.71, MCE. = 12.36, p = 0. 01 respectively. A formal model is presented based on the Receiver Operating Characteristic data to assess data trends for high- and low frequency words. Two differentiated models were obtained: a continuous model based on high frequency stimuli and a threshold model based on low frequency stimuli.