Appendix E: Accessibility index: Responses ranked by how many normed words produce them as associates.

Copyright © Nelson, McEvoy & Schreiber


  1. General Accessibility (0.1 MB)

Format. Appendix E presents all of the responses produced by two or more subjects, their rank in terms of how many normed words produced them as associates, and printed frequency values (Kucera & Francis, 1967). The text file contains three columns separated by commas. It can be opened in StatView or Excel to preserve the separation, or in Word, BBEdit.

Data. Appendix E in the electronic file reports what we call the accessibility index which consists of all the responses in the database ranked by how many normed words produced them as associates. The accessibility index is related to the data presented in Appendix B, but instead of presenting the responses alphabetically followed by the cues that produce them, they are presented by rank. For example, responses of FOOD, MONEY and WATER, were produced as associates, respectively, by 324, 302 and 276 of the normed words appearing in the database. We refer to these values as an accessibility index because they provide a measure of the ease with which a given word comes to mind in free association to a variety of different cues. The assumption is that some words, such as FOOD, are more generally accessible in memory because they are produced by a greater of variety of other words (e.g., Howes, 1957; Rubin & Friendly, 1986). The accessibility index is, in some ways, similar to measures of printed frequency, and we have added frequency values from Kucera & Francis (1967) for the sake of comparison.

Any estimate of accessibility is bound to be biased because it will depend to a great extent upon its source. Kucera and Francis selected 2,000 paragraphs of 500 words resulting in a sample of one million words, whereas the present norms were based on a semi-random sample of 5,019 words producing about 600,000 free association responses by two or more subjects. Despite these differences, the two measures are strongly related, r= .76, n = 10, 470 (this correlation was computed on the log10 of each index, with zero values replaced with 1 before the logs were taken). Rubin and Friendly (1986) report similar results using other free association databases. Although our experience with cued recall suggests that printed frequency and production frequency appear to have similar effects (Nelson & Xu, 1995), Rubin and Friendly (1986) have shown that free recall is better predicted by production frequency or what we call accessibility. Regardless of the high correlation between these two measures, they may be capturing different aspects of experience.