Fig. 1.

Three polymorphic equilibria (two stable, one unstable) can exist with $n=5$ role models. $p\prime -p$ is plotted as a function of $p$ (Eq. 7) for $n=5$, $D\left(3\right)=1.9$, $D\left(4\right)=-0.7$, and $s=0$, shown in blue. The same plot, but with $s=0.05$ (Eq. 13), is shown in red. The black horizontal line illustrates $p=p\prime$, and the equilibria, i.e., solutions to Eq. 10, occur when the colored lines cross the black line, shown with circles. Open circles mark unstable equilibria, and filled circles mark stable equilibria. Arrows point away from unstable equilibria and toward stable equilibria. In the $s=0$ case, there are five equilibria total, with the stable ones at $\widehat{p}=0.1927$ and $1-\widehat{p}=0.8073$. In the $s=0.05$ case, there are also five equilibria, with the stable ones at $\widehat{p}=0.2263$ and 0.8331. Type $A$ is favored if $s>0$, and, in this case, the stable frequency of $A$ is higher than with $s=0$.