Investigating prospective memory commission errors.

Prospective memory (PM) is remembering to execute an intention in the future, such as remembering to buy bread on the way home from work. Commission errors occur when a completed or finished intention is erroneously re-executed. This dissertation investigated the influence of context and delay on commission error risk. In three experiments, participants encoded a PM intention (e.g. press “Q” when you see the target words corn and dancer). In Experiments One and Two, I manipulated the context of the PM procedure where participant’s encountered target words (practice block, active block, or neither) before being instructed that the PM intention was finished. The target words were re-presented in a following finished block. In Experiment One, participants who did not execute the intention during the procedure were significantly more likely to make commission errors compared to participants who executed the intention in the active block. Experiments One and Two also demonstrated that executing the PM intention in a practice context did not decrease commission error risk to the same extent as executing the PM intention in the active context. In Experiment 3, I manipulated the temporal delay between the presentation of the finished instructions and the finished block. Significant differences in commission error risk were not observed between participants with a ten minute delay and participants with a 48 hour delay, but commission error risk was high in both conditions. My experiments highlight the importance of executing a PM intention in the appropriate context before it is finished, especially because an unexecuted PM intention may remain accessible for a minimum of two days. These findings further our understanding of the Zeigarnik effect and of spontaneous retrieval theories of prospective memory