What ties return volatilities to price valuations and fundamentals?

"The relation between the volatility of stocks and bonds and their price valuations is strongly time-varying, both in magnitude and direction, defying traditional asset pricing models and conventional wisdom. We construct and estimate a model in which investors' learning about regular and unusual fundamental states leads to a non-monotonic V-shaped relation between volatilities and prices. Structural forecasts from our model predict future return volatility and covariances with R2 ranging between 40% and 60% at the 1-year horizon. The model's success stems largely from backing out the endogenous and time-varying pro (counter) cyclical weights that investors assign to earnings (inflation) news"--National Bureau of Economic Research web site.