Expression* is the intensity of the participants facial expressions. For this metric we are measuring how much facial movement we are detecting.
How the science works...
For the metric expression/arousal we are measuring the participants’ average expression intensity (this is based on action units - individual components of muscle movements) while watching the stimulus. This score is based on benchmark comparisons (i.e. 50% would mean that the stimulus was at the median of expressive response compared to our benchmark studies, while 90% would mean the viewers displayed more expression than 90% of other stims).
*the expression score is available once benchmarks are built. Prior to this the expression score is calculated as an average over the video for all participants.