As fertility declines, it begins to be selected for. It bottoms out, then will be likely to rebound http://www.princeton.edu/~tvogl/vogl_intergen_dynamics.pdf …pic.twitter.com/uC08Ovop25
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the lower the national fertility, the stronger the selection for "intrinsic desire to complete fertility"
there will be vanishingly few hikikomori in two generations time
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