Table 2.

Ethogram of puppy behaviors used to score their behavioral response to each step of the stranger-approach test [2].

Stage	Response	Definition
Orientation	Orientation	The puppy acknowledges the experimenter (i.e., makes eye contact/ is oriented toward) within 7 s.
	No Orientation	The puppy does not acknowledge the experimenter’s presence within 7 s (or the duration of the step).
Approach	Approach	The puppy moves toward the experimenter (i.e., takes steps toward him/her or leans toward him/her if he/she cannot step any closer).
	Ambivalent Approach	The puppy approaches and retreats or approaches but then stops before reaching the experimenter [38].
	No Approach	The puppy does not approach (i.e., does not move toward the experimenter) [38].
Behavior	Affiliative Behavior	Any behaviors exhibited by the puppy that are intended to facilitate the establishment or reinforcement of a social bond. Examples include approaching the experimenter while maintaining eye contact and/or making physical contact (e.g., licking and touching) with the experimenter. Outgoing The puppy jumps up or “scrambles” at the front of cage and/or attempts to cross/crosses the front barrier of cage and/or exhibits repeated physical contact with the experimenter (e.g., repeatedly licking, jumping on hands, etc.) and/or approaches the experimenter while exhibiting intense tail wagging.
	Undisturbed	The puppy is engaging in an active behavior (e.g., sniffing, eating, etc.) when the step begins, then acknowledges the experimenter’s presence and returns to the same behavior [38].
	Avoid	The puppy avoids the experimenter (i.e., moves away from them and turns its head in the opposite direction) [38].
	Stationary	The dog is in a static posture (i.e., sitting and lying). There may or may not be visual orientation toward the environment. The dog may change posture in place but does not show any displacement [41]
Posture	Normal	“Normal posture under neutral conditions” for specific breed and age [42]
	Low	“Back rounded and/or legs bent…, head lowered” [42].
Additional	Fight/ Aggression	The puppy exhibits aggression (e.g., lunging, growling, teeth baring, etc.) [38].
	Bark	Negative affect Barking associated with avoidance, aggression, frustration, etc. Positive affect Barking associated with play, greeting, excitement, etc.
	Stereotypic Behavior	The puppy performs a pattern of behavior repeatedly (e.g., pacing, circling, etc.) [38].