TABLE 2.

Canine attachment style definitions (adapted from Schöberl et al., 2016 and Thielke et al., 2017).

Attachment Style	Definition
Secure	Dog’s greeting behavior is active, open, and positive. Little or no resistance to contact or interaction with the human participant. Seeks proximity and is comforted upon reunion, returning to exploration or play.
Insecure Ambivalent	Dog shows exaggerated proximity-seeking and clinging behavior (but may struggle if held by human participant). Exhibits a mix of persistent distress with efforts to maintain physical contact with the human participant and/or physically intrusive behavior toward the human participant (Dogs who the judges agreed seemed essentially secure but with ambivalent tendencies were categorized as secure).
Insecure Avoidant	Dog shows little or no visible response to the human participant’s return. Ignores or turns away from human participant but may not resist interaction altogether (e.g., laying, sitting, or standing without physical contact with, out of reach of, or at a distance from human participant).
Insecure Disorganized	Dog exhibits evidence of a strong approach-avoidance conflict or fear upon reunion (e.g., circling human participant, hiding from sight, rapidly dashing away upon reunion, or “aimless” wandering around the room). A lack of coherent strategy is shown by contradictory behavior. Dog may show stereotypies upon reunion (e.g., freezing or compulsive grooming). “Dissociation” may be observed, that is, still or frozen posture, staring into space without apparent cause, for at least 20 s (in a non-resting, non-sleeping dog).
Unclassifiable*	Judges were unable to reach consensus on the attachment style categorization of the dog. Unclassifiable dogs were excluded from further analysis on dog attachment.

*No dogs in the current study were unclassifiable.