People often experience regret when we consider counterfactuals to our past actions, which can help us improve our future behaviours. However, existing developmental measures of regret typically involve no means of foreseeing the eventual outcome, which means that any reported experiences of regret may not aid children in making better choices in similar future situations. We investigated if 4- to 9-year-olds (N = 144) experienced stronger regret towards a choice where they could have foreseen the eventual outcome. Children selected one box each from two pairs of boxes, with both selected boxes leading to sub-optimal outcomes. Critically, one pair of boxes had windows on the bottom, such that children could have apparently foreseen the sub-optimal outcome of their choice if only they had first looked underneath the boxes. Not until 8 years of age did many children feel worse about the box selection with the foreseeable outcome.

The counterfactual emotions of regret and relief arise from considering how the present would look had one taken an alternative past action. We investigated if 4- to 9-year-old children (N = 192) could identify others' regret and relief by watching videos of actors choosing between two boxes that concealed a better or worse prize. Each actor first looked inside the chosen box and made a happy or sad facial expression, and children were then shown the contents of that box. Critically, the actor then looked inside the non-chosen box and made either a happy or sad facial expression, and children were asked what they thought was inside. Children aged 6 years and older were able to identify that the non-chosen box concealed a better prize when the actor was sad, and a worse prize when the actor was happy. The abilities to experience and recognise counterfactual emotions may develop concurrently.