Phase 3: Specification of Stage 2 Processes: Validation of (Hc )

The arbitrariness of categorizing Briggs’ work on the modeling of the binary classification task into four research periods is seen most clearly in this third phase. His earliest work with Blaha led to a rechecking hypothesis to account for certain reaction time (RT) differences between positive and negative stimuli. His study with Swanson that same year introduced the possibility of a binary search process better indexed by log₂M than by (M). Swanson and Briggs developed the initial rationale for using (H_c) as an index of central-processing load in place of (M), the number of items in the positive set, or some other information measure [e.g., stimulus uncertainty (H_s) or response uncertainty (H_r)]. Work on (H_c) began with the several studies that showed a discrepancy between the match and no-match RT functions. This discrepancy was not dealt with for a period of several years during which (H_c) was proposed and developed as a measure of central-processing load.