The prescribed time courses of BrAC(t) in the 2-session design of the slopes experiment. In a 2-segment session (dark dashed line), an individual’s exposure to alcohol was prescribed to rise at a constant rate of 6.0 mg%/min until it reached 68 mg% (11.3 min, then to descend at a constant rate of −1.0 mg%/min. In the 1-segment session, the constant rate of rise was 3.0 mg%/min. These two time courses intersect (“crossover”) at a BrAC of 60mg%, 20 min after the infusions begin. At the crossover point, only the slope of the exposure differs.