Comment by draw_down

Answer: social pressure/coercion.

> Even just showing a smidgen of frustration or irritation was considered weak and childlike, Briggs observed.

Because it's so unacceptable to show anger or frustration, I would suspect there is some release valve for it which is kept under wraps. I don't believe that these things magically disappear just because they're not acceptable.

These researchers who have lived among populations inevitably come away with a perception of that population which reflects what those people wanted to show. Like, if you lived among Catholics for a year in 1974, how much would you learn about the conspiracy to protect priests who abused children? You'd probably learn a hell of a lot more about how they celebrate Christmas or whatever. Nobody wants to talk about the underbelly of their community, people mostly don't even want to acknowledge it to themselves.