Horses and their owners participate in an increasingly diverse range of equestrian pursuits including such activities as racing, show-jumping, endurance riding, carriage driving, dressage, hunting, pony club games, polo and leisure trekking. The majority of owners and riders within the disciplines of equitation appear to have a general preference toward using male horses as the chosen competition animal. Although not exclusively so, stallions and geldings are quite often physically bigger and stronger than fillies and mares and may enjoy some athletic advantage as a result. However, it is known from studies involving humans and small laboratory animals (mice and rats) that some gender differences in cognitive function may also affect performance where tasks involve 3-dimensional objects and elements of depth perception (Morris, Garrud, Rawlins, and O’ Keefe, 1982). The horse has laterally placed eyes (Budiansky, 1997 and Figure 1) and therefore a stereoscopic (binocular) visual field of approximately 65-70°.