This research examined several factors hypothesized to influence the actor-observer effect (AOE). Participants engaged in 3 successive dyadic interactions: after each interaction, they rated the importance of 4 causal factors in influencing their behavior and that of their partner. The AOE held for 1 external factor, interaction partner, and 1 internal factor, personality, but not for situation or mood. Actor and observer attributions changed in predicted ways across the 3 interactions: Actors increasingly emphasized the importance of their partner, whereas observers increasingly emphasized personality: both actors and observers substantially lowered their attributions to the situation. We found consistent individual differences in attributional tendencies that allowed us to predict who showed the AOE. Together, the findings demonstrate that A-O differences depend on: (a) the specific causal factor invoked, (b) the individual's history in the situation, and (c) individual differences among attributors. Discussion focuses on the limited generality of the AOE and the need for a more complex formulation of A-O differences in attribution.