  Disordered and amorphous materials often retain memories of perturbations
they have experienced since preparation. Studying such memories is a gateway to
understanding this challenging class of systems, yet it often requires the
ability to measure local structural changes in response to external drives.
Here we show that dissipation is a generic macroscopic indicator for the memory
of the largest perturbation. Through experiments in crumpled sheets under
cyclic drive, we show that dissipation transiently increases when first
surpassing the largest perturbation due to irreversible structural changes with
unique statistics. This is used to devise novel memory readout protocols based
on global observables only. The general applicability of this approach is
demonstrated by revealing a similar memory effect in a three-dimensional
amorphous solid.
