Research has shown that persons with mixed hand preference (i.e., who report using their non-dominant hand for at least some manual activities) display an increased tendency to update beliefs in response to information inconsistent with those beliefs. This has been interpreted as reflecting the fact that the left hemisphere maintains our current beliefs while the right hemisphere evaluates and updates those beliefs when appropriate. Belief evaluation is thus dependent on interhemispheric interaction, and mixed-handedness is associated with increased interhemispheric interaction. In Experiment 1 mixed-handers exhibited higher levels of persuasion in a standard attitude-change paradigm, while in Experiment 2 mixed-handers exhibited higher levels of gullibility as measured by the Barnum Effect.