Forming a new prospective memory intention can reduce prospective memory commission errors

Previous prospective memory (PM) studies indicate that PM intentions remain active after completion and result in commission errors. In this study, we aimed to investigate the effect of adding a new PM intention in the finished phase on PM commission errors. Eighty-six participants were randomly allocated to one of three groups: a new PM group, a non-new PM group, and an implementation intention group. In the PM finished phase, the non-new PM group performed the 1-back task only, while the new PM group was asked to complete both the 1-back task and a new PM task simultaneously. The implementation intention group adopted the “if-then” encoding strategy to encode the new PM intention and executed a new PM task while performing an ongoing task. We found no difference in the 1-back task among the three groups, but the main difference was reflected in the commission error rate with the rate being highest in the non-new PM group, followed by the new PM group, and lowest in the implementation intention group. These findings suggest that executing a new PM task after the completion of a PM intention or adopting an implementation intention encoding strategy to form a new intention effectively reduces commission errors. Therefore, in real life, when we form new prospective memory intentions, we can strengthen them through encoding strategies during the encoding stage, in order to avoid the occurrence of commission errors as much as possible.