There is considerable controversy about how to conceptualize implicit and explicit attitudes, reflecting substantial speculation about the mechanisms involved in implicit and explicit attitude formation and change. To investigate this issue, the current work examined the processes by which new attitudes are formed and changed and how these attitudes predict behavior. Five experiments supported a systems of reasoning approach to implicit and explicit attitude change. Specifically, explicit attitudes were shaped in a manner consistent with fast-changing processes, were affected by explicit processing goals, and uniquely predicted more deliberate behavioral intentions. On the other hand, implicit attitudes reflected an associative system characterized by a slower process of repeated pairings between an attitude object and related evaluations, were unaffected by explicit processing goals, uniquely predicted spontaneous behaviors, and were exclusively affected by associative information about the attitude object that was not available for higher-order cognition.