Figure 5. Psychometric curves generated by a forced-choice assessment of ambiguous threat show sharpened discrimination between threat and non-threat while breathing stress-derived sweat.
For each participant, data for each condition (STRESS, EXERCISE) were fitted with the sigmoid function, where p 0 and p 0+Δp define upper and lower asymptotes, A0 is the inflection point, and σ defines slope. Significant differences between conditions were seen for slope, with individuals under the STRESS condition more closely approximating ideal perceptual discrimination, shown by the dotted line.