The Sequential categorization identification paradigm: A New paradigm for combined inferences

Systems factorial theory (SFT) focuses on the real-time processing characteristics of encoded representations, allowing for strong tests of hypotheses regarding architecture (serial, parallel, coactive), stopping rule (self-terminating, exhaustive), independence in rate (dependent, independent), and capacity (limited, unlimited, super-capacity). General recognition theory (GRT) focuses on the nature of the encoded representations, allowing for tests of hypotheses regarding perceptual independence, perceptual separability, and decisional separability. For the most part, these two theories have been applied separately, in no small part because the associated experimental methodologies have been distinct. However, recent work applying both approaches with the same observers has illustrated the inferential power that accrues to the combination of methodologies. The present study investigated the potential for a new experimental paradigm to provide, on a set of single trials, the data needed to test hypotheses both about real-time processing characteristics and the nature of the encoded representation. That is a true unified GRT-SFT design. A total of six participants performed 10 sessions each of the new paradigm, the sequential categorization identification paradigm. On each trial, participants first gave a categorization decision that provided the data needed for the SFT analyses. They then gave an identification decision that provided the data needed for the GRT analyses. Feedback on the two decisions was provided only on an initial practice block. Analyses of the data indicated that the new paradigm produced data that were interpretable from both perspectives. Thus, the present study provides a proof of concept that it empirically feasible to assess all the vital characteristic associated with SFT and GRT within the same study and observers.