Table 1. Ethogram of behaviors recorded in the novel object test

Behavioral parameter	Definition
Behavioral score	Rated behavioral reactivity by the experimenter during the test according to the behavioral reactivity scale Table 2.
Escape duration (s)	The time from stimulus initiation to the end of escaping responses. The end point was decided as the point in time when the test horse first stood still, and did not exhibit physical signs of fearfulness over 15 s (e.g., stiff neck muscles and head moving along with the stimulus).