Horses fear reactions can lead to problems such as accidents and injuries to horse and rider. The objective of this work was to identify factors influencing fear in riding horses. Results revealed that riders could induce nervousness in the horse by unconsciously communicating their own nervousness. Riding style also had immediate consequences for fear reactivity in horses: When horses were ridden in the more coercive, and to the horses aversive, Rollkur style, they showed stronger fear than when they were ridden in a regular riding style. In contrast, horses of genetic show-jumping lines...