The Cultural Evolution of Medical Technologies: A Model of Sequential Treatments in the Medical Setting

When people get ill, they naturally want to restore health through medical interventions. Here I model a situation in which individuals can psychologically entertain multiple potential treatments at once: when illness occurs, individuals would attempt one treatment first, and if it fails to produce an observable effect within a particular time period, a second treatment is attempted, and the eventual recovery is attributed to the treatment that is temporally closer. This creates population dynamics wherein the therapeutic power of the superior/effective medical treatments is misattributed to inferior/ineffective treatments. Through both analytic formulation and agent-based simulation, I show that the equilibrium frequencies of different treatment variants depend on their natural variability in the effect timing, the level of individual patience, and the number of cultural models sampled by the naive individual. Both ineffective and effective medical treatments may stably coexist in the population under a range of parameter settings.