Comparison Of Pairwise Dissimilarity And Projective Mapping Tasks With Auditory Stimuli

Two methods for undertaking subjective evaluation were compared: a pairwise dissimilarity task (PDT) and a projective mapping task (PMT). For a set of unambiguous, synthetic, auditory stimuli, the aim was to determine the following: whether the PMT limits the recovered dimensionality to two dimensions; how subjects respond using PMT's two-dimensional response format; the relative time required for PDT and PMT; and hence, whether PMT is an appropriate alternative to PDT for experiments involving auditory stimuli. The results of both Multi-Dimensional Scaling (MDS) analyses and Multiple Factor Analyses (MFA) indicate that, with multiple participants, PMT allows for the recovery of three meaningful dimensions. The results from the MDS and MFA analyses of the PDT data, on the other hand, were ambiguous and did not enable recovery of more than two meaningful dimensions. This result was unexpected given that PDT is generally considered not to limit the dimensionality that can be recovered. Participants took less time to complete the experiment using PMT compared to PDT (a median ratio of approximately 1:4), and employed a range of strategies to express three perceptual dimensions using PMT's two-dimensional response format. PMT may provide a viable and efficient means to elicit up to 3-dimensional responses from listeners.