This research examined the processes by which explicit and implicit attitudes changed to systematically differing levels of counterattitudinal (CA) information. Explicit attitudes changed quickly in response to relatively small amounts of CA information, reflecting rule-based reasoning. On the other hand, implicit attitudes changed more slowly in the face of CA information, reflecting the progressive accretion of evaluation-attitude object pairings. Thus, explicit attitudes were extremely malleable and changed quickly when CA information was presented, however, implicit attitudes revealed a slow, linear change trajectory resulting from the on-going accrual of information about the attitude object. Implications for the processes underlying implicit and explicit attitudes are discussed. Copyright © 2006 John Wiley & Sons, Ltd.