Why Low Fertility Rates Are a Positive Feedback Loop

LessWrong examines a demographic feedback loop: declining birth rates create conditions that reinforce themselves. When birth rates drop, fewer young people enter the workforce, inverting the age pyramid and raising the age at which people can afford to marry and have children. Simultaneously, a shrinking future population reduces investment demand—developers build fewer homes, apartments, and factories—but an aging population holds accumulated savings. This surplus capital chasing limited real investment opportunities drives up asset prices, making housing more expensive just as young people try to start families. The post also traces political consequences: as populations age, older voters gain political power and resist policies like housing construction that might ease family formation costs. Over time, cultural norms adapt to smaller families, cementing the decline. The author frames this as historically unprecedented: for the first time in tens of thousands of years, multiple advanced societies face sustained population contraction.

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