Previous studies evaluating the behavioral responses of horses to different types of bridles found that horses perform at least as well, if not better, with a bitless bridle than a jointed snaffle.

To probe deeper into the issue, Robert Cook, FRCVS, PhD, and Daniel Mills, BVSc, PhD, IL TM, CBiol MIBiol, MRCVS, tested their hypothesis that a horse’s behavior would change–for the better–when ridden with a bitless bridle, compared to a bridle with a bit. (Cook developed and patented the cross-under Bitless Bridle in the United States.)

Four riding school horses, none of which had ever been ridden in a crossunder bitless bridle, were included in the study. The four riders were Certified Horsemanship Association riding instructors and the judge was a CHA Master Clinic Instructor, a Centered Riding Instructor, and a member of the American Judging Association, with 25 years experience. The test was performed during the Certified Horsemanship Association’s International Conference at the Kentucky Horse Park in 2008.

Horses and riders completed a four-minute, 27-phase exercise test first with a bitted then bitless bridle. Each phase was judged using a 10-point scale