A processing device and a method of providing learning capability thereto are provided. A list containing a plurality of listed items with an associated item probability distribution is generated. The item probability distribution comprises a plurality of probability values corresponding to the plurality of listed items. One or more items are selected from the plurality of listed items based on the item probability distribution, a performance index indicative of a performance of the processing device relative to the objective is determined, and the item probability distribution is modified based on the performance index.