Metacognitive training facilitates optimal cognitive offloading.

Cognitive offloading refers to the use of physical actions and the external environment to reduce cognitive demand. Offloading strategies such as creating external reminders instead of relying on internal memory are highly effective and play a key role in supporting real-world cognition. Previous work has shown that people have systematic biases in their offloading strategies, which are related to biased metacognitive evaluations of cognitive ability. While metacognitive interventions could potentially mitigate these biases, research investigating their effects has produced mixed results. Here, we examined the influence of a brief metacognitive intervention comprising just five trials during an initial practice session. After the intervention, participants performed a memory task where they decided between using internal memory (for maximum reward) or external reminders (for reduced reward), allowing us to determine the optimality of offloading strategies. Experiment 1 (N = 164) showed that making metacognitive predictions and subsequently receiving feedback led to improved metacognitive calibration and more optimal reminder-setting strategies. Experiment 2 (N = 416) replicated this pattern and found that making predictions alone was ineffective. These findings suggest that a metacognitive intervention combining prediction with feedback could potentially optimise cognitive offloading in everyday life.