Any theory of information processing must address both what is processed and how that processing takes place. Most studies investigating variables which alter physical dimension utilization have ignored the large individual differences in selective attention or cue utilization. A paradigm was developed using an individual focus on information processing. The purposes of this paper were to: (1) review the essential features of this paradigm, and (2) discuss its use as a beginning step in the investigation of double-aspect, human vs. nonhuman stimuli. Ten double-aspect, human vs. nonhuman stimuli were presented to a heterogeneous sample of 520 first, third, fifth, ninth, eleventh graders, college students, and state hospital patients classified as neurotics, schizophrenics, or sociopaths, for identification. An individual-differences multidimensional scaling analysis resulted in a four-dimensional stimulus space used to subgroup like perceiving people. Characterization of the responses to the double-aspect stimuli by each subgroup demonstrated the value of the approach in studing selective information processing. (Author/BJG)