The effect of the human attachment style of 32 at-risk adolescents on the frequency of avoidance behaviours by therapy horses (n = 9) during the riding component of a 10-week equine-facilitated learning program (mean). The green, red, and blue lines refer to adolescents with a secure, preoccupied, or fearful attachment style, correspondingly. Different letters refer to significant mean differences in the behaviour of therapy horses ridden by adolescents with a secure attachment style across the week of the program (p < 0.05). Differences over time were not significant for the behaviour of horses ridden by adolescents with an insecure attachment style (preoccupied and fearful).