I originally posted this on psychology SE but received no response, so I am cross-posting here. It seems appropriate for philosophy SE because the cultural dependence of ethics is generally a subject of interest to philosophers of ethics. But let me know if there is a more appropriate SE site.
I recently had a conversation with a friend about the psychology of ethics, and it reminded me of an anecdote that I read perhaps 10-15 years ago. The anecdote supposedly originates in the anthropology literature, but I couldn't find an anthropology SE, so I am hoping that someone here will have encountered it. I'm looking for either a reference or perhaps a similar anecdote that does have a reference. If the story can be identified, I'm also interested in how credible the story is (i.e., if there is any known criticism or dispute about it).
I just want to point out in advance that I have no formal training in psychology or anthropology and that I have only read popular literature on these subjects.
I recall picking up a book in a bookstore and reading most of a chapter that was devoted to the idea that most ethical concepts that modern westerners would consider "self-evident" are not universal and are certainly not considered self-evident in many other cultures. One big part of this is the in-group/out-group distinction, where many ethical rules are only considered applicable to the in-group.
As an extreme example, the book related the following story, which comes from an anthropologist who studied the Inuit (or perhaps another Arctic people):
There was a band of Inuit people who were out hunting in a remote area. Some tragedy occurred, and one member of the band died. (I think the tragedy was natural, not human-caused.) Everyone grieved for several hours. Then, in the night, one of the men stood up and shouted, "Shall we suffer, or shall others suffer!?" Four or five of the men got together and went off searching the wilderness for other people. They found a tiny hunting party of strangers, who were all asleep. Then they killed them all. This raised their spirits and they went back to their camp. When questioned, they did not consider this to be ethically problematic at all.
(This retelling is based entirely on my faulty memory.)
I was deeply skeptical of the story when I first read it, but I was also open-minded enough to take it seriously. It is trivial to find examples throughout history of atrocities that are committed against a dehumanized outside group, which lends credence to the argument that humans generally consider ethical prohibitions to only apply within one's own group. It's also conceivable that one's in-group could be small enough that strangers are automatically excluded.
Please let me know if you have read this (or anything similar enough) before and can provide a reference and/or criticism.