What information might be in the facial expressions of ridden horses? Adaptation of behavioral research methodologies in a new field

Horses being ridden when in pain is a welfare concern, which deserves investigation. Transfer of behavior-based pain evaluation systems developed for clinical science to ridden horses must be done with caution, since research methods specific for evaluation of pain in equitation science have not been validated. In this commentary piece, we present some concerns about the study designs of two recent studies evaluating facial expressions in ridden horses.