Data from the two sessions were represented by separate plots, each depicting the percentage of anger responses as a function of adaptation condition and morph percentage.
The point of subjective equality (PSE; the point at which the percentage of the two responses is equal) was estimated for each adaptation condition in each subject by fitting a Weibull function to each response plot
Weibull functions were fit using Sigma Plot Version 10.0 by Systat Software, Inc.
Aftereffects were defined as a statistically significant shift in the balance point (expressed as a percentage morph change) of the face adaptation condition compared to control adaptation.
The magnitude of the aftereffect for each expression condition was also obtained by subtracting the control PSE from the expression PSE.
These values are referred to as ‘difference-scores’.