We may think our dog wIll take a treat from any hand that offers it, but a new study by a team of Japanese researchers suggests that may not be the case. Primates engage in something called “social eavesdropping”— essentially, making judgments about others based on interactions that don’t directly affect their own interests. This study tested dogs’ ability to do the same by setting up situations in which the dogs’ owners asked for help in opening a box and were assisted (helper scenario), rejected (non-helper scenario), or ignored (control scenario) as the dogs looked on. After these interchanges, when the dogs were offered treats, they took them randomly from Helper and Control “strangers” but were biased against non-helpers. According to Kazuo Fujita, professor of comparative cognition at Kyoto university and one of the study’s authors, the ability to socially and emotionally evaluate others “is one of the key factors in building a highly collaborative society.” So, another step in the process of understanding how Canis lupus became familiaris: like humans, dogs are able to pick up clues about who to trust and who to avoid.