  Fe-K$_{\beta}$ X-ray emission spectroscopy measurements reveal an asymmetric
doping dependence of the magnetic moments $\mu_\text{bare}$ in electron- and
hole-doped BaFe$_{2}$As$_{2}$. At low temperature, $\mu_\text{bare}$ is nearly
constant in hole-doped samples, whereas it decreases upon electron doping.
Increasing temperature substantially enhances $\mu_\text{bare}$ in the
hole-doped region, which is naturally explained by the theoretically predicted
crossover into a spin-frozen state. Our measurements demonstrate the importance
of Hund's coupling and electronic correlations, especially for hole-doped
BaFe$_{2}$As$_{2}$, and the inadequacy of a fully localized or fully itinerant
description of the 122 family of Fe pnictides.
