The main purpose of this thesis is to study the relationship between regret and changing your mind in decisions where there is a time period between the choice and when the outcome is revealed. Do people experience regret before as well as after the outcome is known? If so, do they experience more regret after the outcome if they have the option to change their mind, and do so? To answer these two questions three experiments were performed. In Study 1 and Study 2 the participants were given the impression that the result was at least partly based on their skill in offering money to a simulated opponent. Half the participants were given the opportunity to change their mind. In the first study the participants' reported regret before the outcome was significantly higher than the regret reported post-outcome, while in the second study it was equal. In both studies those who changed their choice before the outcome reported more regret both not only before, but also after the outcome, compared to those who did not change. To further explore the effect of changing your mind a third study was performed. Even when changing your mind was the best strategy those who did so reported a higher amount of regret than those who did not. Results indicate that there is a significant amount of regret before the outcome is known, and that the act of changing your mind has an effect on the amount of experienced post-outcome regret.