  We study the deviations from perfect memory in negative temperature cycle
spin glass experiments. It is known that the a.c. susceptibility after the
temperature is raised back to its initial value is superimposed to the
reference isothermal curve for large enough temperature jumps DT (perfect
memory). For smaller DT, the deviation from this perfect memory has a striking
non monotonous behavior: the memory anomaly is negative for small DT's, becomes
positive for intermediate DT's, before vanishing for still larger DT's. We show
that this interesting behavior can be reproduced by simple Random Energy trap
models. We discuss an alternative interpretation in terms of droplets and
temperature chaos.
