This study tested whether a brief manipulation consisting of positive future thinking can temporarily increase optimism. Participants in the positive future thinking condition (n = 44) wrote about their best possible self (BPS) for 15 min, followed by 5 min of mental imagery. Participants in the control condition (n = 38) wrote about and imagined a typical day in their life. Positive and negative future expectancies and positive and negative affect were measured before and after each manipulation. Compared to the control manipulation, the positive future thinking manipulation led to significantly larger increase in positive affect and positive future expectancies. The increase in positive expectancies was not dependent on the mood effect. The results indicate that imagining a positive future can indeed increase expectancies for a positive future.
Peters et al. (Sat,) studied this question.