Cognitive offloading weakens the neural representation of to-be-remembered information

People tend to forget information once they offload it to an external reminder such as a written note or computer file. However, the neural basis for this so-called “Google effect” or “digital amnesia” is unknown. We used fMRI to ask: A) to what extent does brain activity overlap between cognitive offloading and deliberate forgetting, and B) what is the neural fate of offloaded information? Participants viewed face or scene pictures, then received a cue either to A) remember them for a memory test, B) offload them, meaning that the test would come with a reminder, or C) forget them because there would be no test. Offload cues generated brain activity that closely resembled forget cues. Moreover, multivariate pattern analysis showed that the neural trace of to-be-remembered information persisted in the remember condition but faded until it was statistically absent in both the offload and forget conditions, which did not differ from each other. Therefore, when people offload memories into external technology, this has similar neural correlates to deliberate forgetting, leading to a weakened neural representation of to-be-remembered information. We argue that this may be an adaptive process that prioritises the most valuable information for limited-capacity neural systems.