Interaction between trend followers and fundamentalists and share price dynamics

There are often thought to be two types of equity investors: Trend followers , who buy shares when share prices have recently risen; Fundamentalists, who buy shares when share prices are lower than fundamental equity values. The interaction of these two types of equity investors, which can actually be observed after shocks, can generate various share price dynamics (stable, unstable, oscillating, etc.). If we add the assumption that when share prices deviate far from fundamental equity values, the proportion of fundamentalists (who play the return towards fundamental value) increases, then we obtain a complex dynamics (increasingly large oscillations followed by a return towards fundamentals) that can resemble reality.