I get how their might be threshold effects for low hand-washing/vaccination rates, but how are seatbelts and raw-milk consumption multiplicative and rather than additive risks?

It's funny how one of the most important improvements in patient welfare in the history of medicine happened for reasons unrelated to measurement of patient welfare.

Bloodletting was sustained - at least in doctors' imagination - by a hydraulic model: good for repairing flow. But as the model of the body become influenced by thermodynamics, doctors took against things that "wasted energy": This included masturbation, shaving and bloodletting.

We find would-be caregivers are more inclined to help people who undergo treatment and that people with chronic pain + legitimacy concerns are keener on aversive treatment.

In other words: we develop signalling perspective on medical (over)use.