Does expecting an external store impair memory for expository texts? Investigating cognitive offloading of text passages

People often use external tools to support their memory, which can cause memory impairments for information expected to be externally accessible, effects often attributed to cognitive offloading. Memory offloading research has predominantly used facts or word lists, so little is known about the effects of store expectancy on longer texts. Three experiments investigated how anticipating external access to a passage influences memory for that passage. Participants read expository texts, one of which they expected to access during a later multiple-choice memory test, and one they did not expect to be able to access. In Experiment 1, participants had full control of their reading time. In Experiment 2, participants were required to spend a minimum time reading. In both experiments, participants spent less time reading the passage they expected to access at test. In Experiment 3, reading time was fully controlled. Participants also reported their subjective reading effort and gave metacognitive predictions of their test performance. Across all experiments, participants scored lower on the memory test when they anticipated access to the passage than when they did not, and reading time mediated the relationship between store expectancy and condition. These results indicate that offloading-related memory impairments extend to informational text passages, even when time spent reading the passages is controlled.