We explored the possibility that the encoding flexibility processes postulated by Sherman and colleagues (1998) may also apply to intentional impression formation settings, even when cognitive resources are available to conceptually encode all of the behavioral information regardless of the relation of that information to the initial stereotypical expectancies. Three experiments offer evidence for the lower conceptual fluency for expectancy-incongruent behaviors, compared with congruent behaviors, as well as for the consequences of that difference for impression formation.Experiment 1 shows that incongruent behaviors are perceived as more difficult to understand in meaning. Experiment 2 links this lower conceptual fluency with a better discrimination of the specific trait implications of the behaviors. We further explore the role of conceptual encoding difficulty for developing personality impressions (Experiment 3). These studies reveal the implications of initial expectancies for the differential conceptual encoding of congruent and incongruent behaviors, even when the availability of cognitive resources is high, such as when forming an intentional impression about a person's personality. The link between this process and encoding the trait implications of behaviors may shed new light on impression formation processes and demand a revision of some of the assumptions that were made by the classical person memory model. We contend that behavior encoding in impression formation is likely to begin with default trait encoding but will be inhibited when the implications of the behavior conflict with previous trait expectancies (see also Wigboldus, Dijksterhuis, & van Knippenberg, 2003).