Somewhat low-effort answer:
I know Doing Good Better mentions the logarithmic relationship between income and wellbeing in one of its earlier chapters.
Relevant posts/articles:
https://ourworldindata.org/happiness-and-life-satisfaction#looking-across-and-within-countries
https://forum.effectivealtruism.org/posts/PPNgQSvKrcKvsM2ZN/the-effect-of-cash-transfers-on-subjective-well-being-and
Somewhat low-effort answer:
I know Doing Good Better mentions the logarithmic relationship between income and wellbeing in one of its earlier chapters.
Relevant posts/articles:
https://ourworldindata.org/happiness-and-life-satisfaction#looking-across-and-within-countries
https://forum.effectivealtruism.org/posts/PPNgQSvKrcKvsM2ZN/the-effect-of-cash-transfers-on-subjective-well-being-and