Unprimed stem completion is only moderately predicted by word frequency and length

Factors that determine unprimed performance in word-stem completion were investigated. Researchers' descriptions of materials used in word-stem completion suggest that normative word frequency, number of alternative completions, and response length are believed to be important. A total of 160 students provided normative responses to each of 914 multiple-completion three-letter word stems, resulting in over 12,000 unique responses. Although the number of alternative responses made correlated well with the number possible, word frequency and length were extremely variable in their relation to response frequency across stems. Creating more precise materials for implicit memory studies appears to require consulting normative response data.