A taxonomy of mental time travel and counterfactual thought: Insights from cognitive development.

Humans often engage in complex thought about the past, present, and future. They not only think about what did happen, is happening, and will happen, but also what did not happen, is not happening, and will not happen. Here we present an integrated taxonomy of mental time travel and counterfactual thought, in which event representations are assigned categorically distinct temporal locations (i.e., past, present, or future) and subjective propositional values (i.e., affirmed, negated, or uncertain). We review research on children's developing abilities to generate and reason about event representations with these characteristics. We find that children's development typically proceeds in three stages: (1) the capacity to imagine and reflect on affirmed and uncertain past, present, and future outcomes, (2) the capacity to imagine and reflect on counterfactual, negated versions of known past outcomes and present situations, and (3) the capacity to anticipate experiencing counterfactual emotions (i.e., regret and relief) in the future. This protracted developmental trajectory may be a function of increasing executive demands, increasing hierarchical complexity of temporal representations, or both.