The four-alternative forced choice (4-AFC) is one of a family of m-AFC tests used in Psychology. Based on a detection-theoretic model, for a given d' it is slightly more powerful than the 3-AFC and 2-AFC. Although its potential use in sensory food science is limited, there are occasions when it will be used. Accordingly, tables of d' values for given proportions of correct responses (pc) along with corresponding values of B, for computing variances, are given in this paper. Power comparisons are also made between 2-AFC, 3-AFC and 4-AFC tests.