No “Thank You!”
When beginning my fieldwork among the Dorzé of Southern Ethiopia many years ago, I thought that it would be better, at least initially, to be too polite rather than not polite enough. I would say “Thank you!” as much or more than I did in France, for minor services such as being given food, shown the way, helped to reach an object, and even at the end of a transaction, when buying something at the market for instance. I was soon made to understand that my behaviour was bizarre and indeed inappropriate. It was not that people were less cooperative or mutually helpful than in France, far from it. Nor did I have reason to think that they felt less grateful. It was that “thank you” was not expected, which I found mildly puzzling.
I speculated that it had to do with a linguistic difference: the expression that best translates “thank you” into Dorzé is far from being a perfect synonym. “Ts’os ingo!” is a proper blessing meaning “May God give you!” This blessing is used not only as an expression of gratitude for out-of-the ordinary services or gifts, but also when declining to give to a beggar (whereas saying “thank you” to European beggar when not giving would be, if anything, offensive). It is also commonly used to praise a good deed of somebody who is not present: “May God give to Girma!”
I hadn’t given much more thought to this minor ethnographic observation until now. Today, however, I have enjoyed reading “Universals and cultural diversity in the expression of gratitude”  by Simeon Floyd, Giovanni Rossi, Julija Baranova, Joe Blythe, Mark Dingemanse, Kobin H. Kendrick, Jörg Zinken, and Nick Enfield (in Royal Society Open Science). Here is the abstract:
“Gratitude is argued to have evolved to motivate and maintain social reciprocity among people, and to be linked to a wide range of positive effects—social, psychological and even physical. But is socially reciprocal behaviour dependent on the expression of gratitude, for example by saying ‘thank you’ as in English? Current research has not included cross-cultural elements, and has tended to conflate gratitude as an emotion with gratitude as a linguistic practice, as might appear to be the case in English. Here, we ask to what extent people express gratitude in different societies by focusing on episodes of everyday life where someone seeks and obtains a good, service or support from another, comparing these episodes across eight languages from five continents. We find that expressions of gratitude in these episodes are remarkably rare, suggesting that social reciprocity in everyday life relies on tacit understandings of rights and duties surrounding mutual assistance and collaboration. At the same time, we also find minor cross-cultural variation, with slightly higher rates in Western European languages English and Italian, showing that universal tendencies of social reciprocity should not be equated with more culturally variable practices of expressing gratitude. Our study complements previous experimental and culture-specific research on gratitude with a systematic comparison of audiovisual corpora of naturally occurring social interaction from different cultures from around the world.”
Excellent work, congratulation to the authors, and thank you (but not “Ts’os ingo!”) for helping me better understand why I had been overpolite.
 Universals and cultural diversity in the expression of gratitude