  The necessity of having an electronic device working in relevant biological
time scales with a small footprint boosted the research of a new class of
emerging memories. Ag-based volatile resistive switching memories (RRAMs)
feature a spontaneous change of device conductance with a similarity to
biological mechanisms. They rely on the formation and self-disruption of a
metallic conductive filament through an oxide layer, with a retention time
ranging from a few milliseconds to several seconds, greatly tunable according
to the maximum current which is flowing through the device. Here we prove a
neuromorphic system based on volatile-RRAMs able to mimic the principles of
biological decision-making behavior and tackle the Two-Alternative Forced
Choice problem, where a subject is asked to make a choice between two possible
alternatives not relying on a precise knowledge of the problem, rather on noisy
perceptions.
