NEW YORK (AP) — It’s the season of giving thanks — and it turns out humans have been doing it for a long, long time. “This is something that is part of our human DNA,” said Sarah Schnitker, a psychologist at Baylor University. “It is a glue, in a sense, that holds us together.”How we got gratefulPolitical Cartoons View All 1260 ImagesHumans are social animals. Some scientists think the feeling of gratitude evolved to keep the helping exchanges going. Though we can’t “speak chimp” well enough to know if they’re actually saying thanks, Suchak added, it makes sense that some form of this social debt showed up early in our lineage.

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Persons: —, they've, ”, Sarah Schnitker, Michael Tomasello, Malini Suchak, capuchin, Suchak, Jenae Nelson, ” Nelson, they’re, Amrisha Vaish, Vaish, Schnitker, Nelson, “ It’s, “ Organizations: Baylor University, Duke University, Canisius University ., Baylor, Harvard, University of Virginia, Associated Press Health, Science Department, Howard Hughes Medical Institute’s Science, Educational Media Group, AP