<p>Influential cognitive science theories postulate that decision-making is based on treating expected outcomes as incentives according to a reward function. Yet a systematic analysis of the learning processes that determine the reward function remains to be carried out. The paper fills this gap by examining the contribution of two fundamental learning processes: <i>conditioned reinforcement</i>, occurring either via direct or via vicarious experience, and <i>imitative incentive learning</i>, at play when an agent appropriates the incentives sought by another individual. From an evolutionary perspective, the two processes appear to be adaptive insofar as conditioned reinforcement might have evolved to simplify decision-making, while imitative incentive learning might have arisen to harness the full potential of social learning and to facilitate cooperation. The paper contributes to research on decision-making by offering a detailed analysis of the learning mechanisms that drive acquisition of the reward function.</p>