Learning rules of a forgetful memory generate their synaptic efficacie
s through iterative procedures that operate on the input data, random
patterns. We analyse invariant distributions of the synaptic couplings
as they arise asymptotically and show that they exhibit fractal or mu
ltifractal properties. We also discuss their dependence upon the learn
ing rule and the parameters specifying it, and indicate how the nature
of the invariant distribution is related to the network performance.