Offloading memory leaves us vulnerable to memory manipulation.

We often offload memory demands onto external artefacts (e.g., smartphones). While this practice allows us to subvert the limitations of our biological memory, storing memories externally exposes them to manipulation. To examine the impact of such manipulation, we report three experiments, two of which were pre-registered. Individuals performed a memory task where they could offload to-be-recalled information to an external store and on a critical trial, we surreptitiously manipulated the information in that store. Results demonstrated that individuals rarely noticed this manipulation. In addition, when individuals had information inserted into their external memory stores, they often encoded it into their biological memory, thereby leading to the creation of a false memory. The reported results highlight one of the cognitive consequences of offloading our memory to external artefacts.