The magnitude of perceptual asymmetry (PA) on a CVC fused dichotic words test and on VCV and CV fused nonsense syllables tests were compared. In each test the set of distinguishing phonemic cues was the same; the six English stop consonants, b,p,d,t,g,k. Although test-retest reliability was very high on all three tests there was no correlation across individuals between the degrees of PA on different tests. Moreover, the magnitude of PA on the VCV nonsense test increased as field dependence (FD) increased on the field dependence index (FDI) of the WAIS while there was no relationship between FD and the magnitude of PA on the CVC words test. In addition, concurrent visual tasks increased PA on the VCV nonsense test and decreased it on the words test. In order to facilitate the use of such data, Kimura's classical model of the physiological basis of PA is modified by including components of primary receptive and secondary and tertiary associative function. Comparison of highly similar PA measures, that differ in specific ways, is discussed as a means of collecting data for mapping cerebral functional space and exploring brain-behavior relationships.