A computer-implemented method, comprising: identifying, by one or more processors, a user declaration received at a computing device; identifying, by one or more of the processors, based on the user declaration, a plurality of candidate responsive actions that can be initiated by the computing device in response to the user declaration; determining, by one or more of the processors, based on a history of interaction between the user and one or more computing devices operated by the user, a probability that initiation of each candidate responsive action will be responsive to the user declaration; non-deterministically selecting, by one or more of the processors, a single candidate responsive action of the plurality of candidate responsive actions to be exclusively initiated on the computing device in response to the user declaration, wherein the single candidate responsive action is selected in accordance with the probability that initiation of the candidate responsive action will be responsive to the user declaration; exclusively initiating, by one or more of the processors, the single candidate responsive action on the computing device; and altering, by one or more of the processors, the probability associated with the initiated responsive action based on one or more interactions between the user and the computing device following initiation of the selected action, wherein the one or more interactions between the user and the computing device include rejection of the selected responsive action and manual initiation of an alternative candidate responsive action, and wherein the altering comprises altering the probability associated with the selected responsive action by an amount that is inversely proportionate to a measure of similarity between the selected responsive action and the alternative candidate responsive action. identifying, by one or more processors, a user declaration received at a computing device; identifying, by one or more of the processors, based on the user declaration, a plurality of candidate responsive actions that can be initiated by the computing device in response to the user declaration; determining, by one or more of the processors, based on a history of interaction between the user and one or more computing devices operated by the user, a probability that initiation of each candidate responsive action will be responsive to the user declaration; non-deterministically selecting, by one or more of the processors, a single candidate responsive action of the plurality of candidate responsive actions to be exclusively initiated on the computing device in response to the user declaration, wherein the single candidate responsive action is selected in accordance with the probability that initiation of the candidate responsive action will be responsive to the user declaration; exclusively initiating, by one or more of the processors, the single candidate responsive action on the computing device; and altering, by one or more of the processors, the probability associated with the initiated responsive action based on one or more interactions between the user and the computing device following initiation of the selected action, wherein the one or more interactions between the user and the computing device include rejection of the selected responsive action and manual initiation of an alternative candidate responsive action, and wherein the altering comprises altering the probability associated with the selected responsive action by an amount that is inversely proportionate to a measure of similarity between the selected responsive action and the alternative candidate responsive action.