The role of the image of a conspecific in the regulation of stereotypic head movements in the horse

Weaving was significantly less when the horses were provided with the image of a horse's face (mean percentage of observations ± S.E.M.; 5.56 ± 1.57), compared to both the pixilated (14.85 ± 3.06) and white (20.52 ± 4.12) images. Nodding was significantly less when provided with the true image of a horse (0.45 ± 0.15) compared to the pixilated image (2.15 ± 0.67). The pattern of weaving throughout the day differed from that of nodding, and together these results suggest that the two behaviours are not analogous. The presence of the image of the horse's face was associated with a significant increase in alertness (F112,2 = 11.31, p < 0.001) and recorded time spent looking at the poster(F112,2 = 3.46, p < 0.05). The timing of stereotypic head movements in the horse in this study suggests that they are not associated with boredom, or lack of stimulation but rather acute frustration.