Is this love? Sex differences in dog-owner attachment behavior suggest similarities with adult human bonds

Sex differences in the behavioral responses of Labrador Retriever dogs in the Strange Situation Test were explored. Behaviors expressed by dogs during seven 3-min episodes were analyzed through a Principal Component Analysis (PCA). The scores of factors obtained were analyzed with a Generalized Linear Mixed Model to reveal the effects of the dog’s sex and age and the owner’s sex. In Episode 1 (dog and owner) and 5 (dog alone), the PCA identified three and two factors, respectively, which overall explained 68.7% and 59.8% of the variance, with no effect of sex. In Episodes 2 (dog, owner, and stranger), 3 and 6 (dog and stranger), and 4 and 7 (dog and owner), the PCA identified four factors, which overall explained 51.0% of the variance. Effects of sex were found on: Factor 1 (distress), with lower scores obtained by females in Episode 2 and higher in Episode 3; Factor 2 (sociability), which was overall higher in females; Factor 3 (separation-distress), with females, but not males, obtaining higher scores when left with the stranger than when with the owner. Therefore, females were overall more social but seemed more affected than males by the owner’s absence. Parallels can be traced between our results and sex differences found in adult human romantic attachment, suggesting that the dog-owner bond has characteristics that are not found in the infant-mother relationship.

Infantilizing Companion Animals through Attachment Theory: Why Shift to Behavioral Ecology-Based Paradigms for Welfare

Attachment theory, proposed in the 1950s to understand the development of parent-child relationships, is often applied to human–companion animal relationships. I argue the application of this paradigm to test nonhuman animals’ social bonds with humans infantilizes mature animals and has a detrimental impact on animal welfare. The premise is that Ainsworth’s Strange Situation Test is inappropriate to investigate the emotional ties between domestic animals and humans. Instead, I propose an alternative theory, that dogs form mature social bonds with their guardians, and that the phenomenon known as separation anxiety is the result either of the frustration of mature adult group behaviors, or an overdependency fostered by the guardian. Rather than view mature dogs as comparable to human infants in their social relationships, we should perceive them as socially and emotionally mature at adulthood and shift the focus from attachment-based paradigms to the behavioral ecology and cognition of companion animals.

Hand-reared wolves show similar, or stronger, attachment toward human caregivers compared to hand-reared dogs

Domesticated animals are generally assumed to display increased sociability towards humans compared to their wild ancestors. Dogs (Canis familiaris) have the ability to form lasting attachment, a social bond based on emotional dependency, with humans and it has specifically been suggested that this ability evolved post-domestication in dogs. Subsequently, it is expected that dogs but not wolves (Canis lupus), can develop attachment bonds to humans. However, while it has been shown that 16-weeks-old wolves do not discriminate in their expression of attachment behaviour toward a human caregiver and a stranger when compared to similar aged dogs, wolves at the age of eight weeks do. This highlights the potential for wolves to form attachment to humans, but simultaneously raises the question if this attachment weakens over time in wolves compared to dogs. Here we used the Strange Situation Test (SST) to investigate attachment behaviour expressed in hand-reared wolves and dogs toward a human caregiver at the age of 23 weeks. Both wolves and dogs expressed attachment toward a human caregiver. Surprisingly, wolves, but not dogs, discriminated between the caregiver and a stranger by exploring the room more in the presence of the caregiver compared to the stranger and greeting the caregiver more than the stranger. Our results thereby suggest that wolves can show attachment toward humans comparable to that of dogs at later developmental stages. Importantly, our results indicate that the ability to form attachment with humans did not occur post-domestication of dogs.

Differences in greeting behaviour towards humans with varying levels of familiarity in hand-reared wolves ( Canis lupus )

Socialized wolves' relationship with humans is a much debated, but important question in light of dog domestication. Earlier findings reported no attachment to the caretaker at four months of age in a Strange Situation Test, while recently attachment to the caretaker was reported at a few weeks of age in a similar paradigm. To explore wolf–human relationship, we analysed behaviours of hand reared, extensively socialized wolves towards four visitor types: foster-parents, close acquaintances, persons met once before, and complete strangers during a greeting episode. As hypothesized, in the greeting context subjects showed more intense and friendly behaviour towards foster-parents, than other visitor types, which may reflect familiarity and affinity. However, differences were more pronounced in the group situation (at six months of age) than in the individual situation (at 12 and 24 months), suggesting that unique status of foster parents may become less distinct as wolves get older, while exploration of novel social agents is expressed more with older age. Fear related behaviour patterns were only found in the individual situation, mainly displayed towards strangers. We showed that, in case of extensively socialized wolves, distinctive affiliation and affinity towards the foster parent prevails into adulthood.

Owners as a secure base for their dogs

A modified version of the Ainsworth Strange Situation Test was used to analyse 40 dog–owner pairs in order to assess whether owners can represent a secure base for their dogs. The Wilcoxon test revealed significant differences between owner and stranger for protest at separation (whining), contact maintenance effect (proximity, attention seeking and physical contact) and secure base effect (exploration, individual play and social play). The results suggest that dogs behave similarly to children towards the mothers and to chimpanzees towards human caretakers in the Ainsworth Strange Situation Test: owners are the preferred recipient of affiliative behaviours and, in their absence, dogs show behaviours indicative of distress. After reunion with the owner, dogs show an increase in social behaviours towards him/her. Dogs did not show fear of the stranger, and it was regarded as a normal behaviour for adult well-socialized dogs. Until now whether owners represented a secure base for their dogs was debated, due to controversial results. This study found that dogs play and explore more when owners were present, suggesting that owners can represent a secure base for their dogs. Therefore, according to Bowlby’s definition, dogs are linked to their owners by an attachment bond.