Unrealistic personal optimism is the perception that undesirable events are less likely and desirable events are more likely to happen to oneself than they are to happen to other similar people. Three experiments were performed to study the relationships among personal optimism, perceived control, and selective activation of the cerebral hemispheres. This selective activation was produced by the manipulation of lateral attentional orientation. Right-handed college students were subjects for all three experiments. Experiment 1 (N=40) attempted to replicate the effect of greater personal optimism for future events during relative left than during relative right hemisphere activation. It was further tested whether personal optimism would be predicted by scores on the Desirability of Control scale. The results confirmed both hypotheses and the orientation effect was extended from visual to auditory attention. Because both hemisphere activation and perceived control influenced optimism, Experiment 2 (N=37) was performed to test the hypothesis that manipulated hemisphere activation would alter trait control as measured by several scales. The data failed to support the hypothesis, but produced an unexpected finding that the correlations among the different scales were significantly higher during left than during right hemisphere activation, lending support to consistency as a mediator of the lateralized optimism effect. In Experiment 3 (N=43), the manipulation produced higher perceived control over the outcome of future events during relative right hemisphere activation than during left, in male but not female subjects. (Methods and results for all three experiments are detailed and an extensive list of references is provided.) (Author/NRB)