In cognitive science, choice-supportive bias is the tendency to retroactively ascribe positive attributes to an option one has selected. It is a cognitive bias. For example, if a person buys a computer from Apple instead of a computer running Windows, he is likely to ignore or downplay the faults of Apple computers while amplifying those of Windows computers. Conversely, he is also likely to notice and amplify advantages of Apple computers and not notice or de-emphasize those of Windows computers.

What is remembered about a decision can be as important as the decision itself, especially in determining how much regret or satisfaction one experiences. Research indicates that the process of making and remembering choices yields memories that tend to be distorted in predictable ways. In cognitive science, one predictable way that memories of choice options are distorted is that positive aspects tend to be remembered as part of the chosen option, whether or not they originally were part of that option, and negative aspects tend to be remembered as part of rejected options. Once an action has been taken, the ways in which we evaluate the effectiveness of what we did may be biased. It is believed this may influence our future decision-making. These biases may be stored as memories, which are attributions that we make about our mental experiences based on their subjective qualities, our prior knowledge and beliefs, our motives and goals, and the social context. True and false memories arise by the same mechanism because when the brain processes and stores information, it cannot tell the difference from where they came from.