This dissertation examines dominance, play, affiliation and social preferences in a group of 24 domestic dogs that socialize regularly at a dog daycare facility. In Chapter 1, we analyzed the frequencies and directions of aggression, submission, and dominance displays. The distribution of submission and aggression resulted in a significantly linear hierarchy in the group, and submission was the best indicator of dominance relationships. Age was significantly correlated with dominance rank with older dogs out-ranking younger dogs. Muzzle-licking met most of the criteria for a formal display of submission in dogs, but was displayed in only 18% of relationships.

Only 29% of all possible pairs had discernable dominance relationships. In Chapter 2, we examined the relationship between agonism, play and affiliation. Twenty-two percent of all possible pairs had known dominance relationships and also exchanged friendly behaviors (formal relationships), 21% of all pairs exchanged friendly behavior but had no discernable dominance relationship (egalitarian relationships), 50% of all pairs were never observed exchanging friendly or agonistic behaviors (non-interactive relationships), and 7% of pairs had known dominance relationships but did not exchange friendly behavior (agonistic relationships). Friendly behavior was much more frequent than agonistic behavior, and we found a complex association between the two. Egalitarian relationships as well as play and affiliation were more common between males and females than between same-sex pairs. Relationship affinity (an index combining play and affiliation) did not significantly differ in formal versus egalitarian relationships, but the latter were significantly more equitable and playful.

In Chapter 3, we investigated patterns of interventions during dyadic play. Interveners directed either (1) a playful behavior at one of the dogs (the target), (2) an affiliative behavior at the target, or rarely, (3) an aggressive behavior at the target. Individual rank did not influence individual interventions rates. Rank relationships between interveners, targets and non-targets did not influence playful interventions. Dogs tended to target higher-ranking dogs during affiliative interventions and target lower-ranking dogs during aggressive interventions, but the latter were too infrequent to apply statistical analyses. Dogs tended to target their preferred partners ("friends") during play more than support them.