Our furry friends can read us like a book, according to a new study.

By Abigail Wise
Updated February 13, 2015
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There's nothing like a wagging tail to cheer you up after a bad day. Science even shows that dogs may reduce feelings of anxiety and loneliness. But our furry friends don't only contribute to our good moods—they might even be able to recognize them. New research shows that dogs may be able to tell when we're happy just by looking at our faces.

The study, published in the journal Current Biology, rewarded a group of dogs for recognizing both happy and angry faces. Each dog was individually shown only the eyes, the mouths, or the left half of the faces of smiling and angry humans. One group of animals saw the same faces they were trained with, and the others were given new faces to look at during the test. In the study, scientists rewarded half of the dogs for recognizing happy faces and the other half for recognizing angry ones.

In their results, the scientists saw one overarching trend: The dogs who were rewarded for the smiling faces learned to discriminate between the two feelings faster than the ones that were rewarded for frowning faces. The paper points out that we'd expect these outcomes if the dogs had been punished when shown the angry faces, but they were actually rewarded for both frowning and smiling faces. The bottom line? The results of the study may be a sign that dogs not only notice a difference in our facial expressions, but might even understand them to a certain extent. So next time you see your pooch wagging his tail, go ahead and smile back.