Cognitive offloading is value-based decision making: Modelling cognitive effort and the expected value of memory

Abstract

How do people decide between maintaining information in short-term memory or offloading it to external reminders? How does this affect subsequent memory? This article presents a simple computational model based on two principles: A) items stored in brain-based memory occupy its limited capacity, generating an opportunity cost; B) reminders incur a small physical-action cost, but capacity is effectively unlimited. These costs are balanced against the value of remembering, which determines the optimal strategy. Simulations reproduce many empirical findings, including: 1) preferential offloading of high-value items; 2) increased offloading at higher memory loads; 3) offloading can cause forgetting of offloaded items (‘Google effect’) but 4) improved memory for other items (‘saving-enhanced memory’); 5) reduced saving-enhanced-memory effect when reminders are unreliable; 6) influence of item-value: people may preferentially offload high-value items and store additional low-value items in brain-based memory; 7) greatest sensitivity to the effort of reminder-setting at intermediate rather than highest/lowest levels of task difficulty; 8) increased offloading in individuals with poorer memory ability. Therefore, value-based decision-making provides a simple unifying account of many cognitive offloading phenomena. These results are consistent with an opportunity-cost model of cognitive effort, which can explain why internal memory feels effortful but reminders do not.