  Memory effects are a key feature in the description of the dynamical systems
governed by the generalized Langevin equation, which presents an exact
reformulation of the equation of motion. A simple measure for the estimation of
memory effects is introduced within the framework of this description.
Numerical calculations of the suggested measure and the analysis of memory
effects are also applied for various model physical systems as well as for the
phenomena of ``long time tails'' and anomalous diffusion.
