Prospective memory

Prospective memory is a form of memory that involves remembering to perform a planned action or recall a planned intention at some future point in time. Prospective memory tasks are common in daily life and range from the relatively simple to extreme life-or-death situations. Examples of simple tasks include remembering to put the toothpaste cap back on, remembering to reply to an email, or remembering to return a rented movie. Examples of highly important situations include a patient remembering to take medication or a pilot remembering to perform specific safety procedures during a flight. Prospective memory is a form of memory that involves remembering to perform a planned action or recall a planned intention at some future point in time. Prospective memory tasks are common in daily life and range from the relatively simple to extreme life-or-death situations. Examples of simple tasks include remembering to put the toothpaste cap back on, remembering to reply to an email, or remembering to return a rented movie. Examples of highly important situations include a patient remembering to take medication or a pilot remembering to perform specific safety procedures during a flight. In contrast to prospective memory, retrospective memory involves remembering people, events, or words that have been encountered in the past. Whereas retrospective memory requires only the recall of past events, prospective memory requires the exercise of retrospective memory at a time that has not yet occurred. Prospective memory is thus considered a form of 'memory of the future'. Retrospective memory involves the memory of what we know, containing informational content; prospective memory focuses on when to act, rather than focusing on informational content. There is some evidence demonstrating the role of retrospective memory in the successful execution of prospective memory, but this role seems to be relatively small. There are two types of prospective memory: event-based and time-based prospective memory. Event-based prospective memory involves remembering to perform certain actions when specific circumstances occur. For example, driving past the local library cues the remembrance of the need to return an overdue book. Time-based prospective memory involves remembering to perform an action at a particular point in time. For example, seeing that it is 10:00 PM acts as a cue to watch a favorite television show. Research performed by Sellen et al. (1997) compared event-based and time-based cues on prospective memory tasks. The experimenters gave participants a place (event-based cue) and a time (time-based cue) and were told to press a button each time those cues appeared during the study. It was found that performance on event-based tasks was better than performance on time-based tasks, even when participants took more time to think about their responses. The difference in task performance between the two types of prospective memory suggests that the intended action was better triggered by external cues of the event-based task than internal cues of the time-based task. External cues, as opposed to internal cues, act as a prompt for better performance, making it easier to complete event-based tasks. McDaniel et al. (2004) further distinguished event-based prospective memory into immediate-execute tasks and delayed-execute tasks. Immediate-execute tasks involve a response as soon as a particular cue is noticed, while delayed-execute tasks involve delays between the perception of the relevant cue and the performance of the intended action. Delayed-execute tasks more commonly occur in real life when circumstances of a situation prevent intermediate action once the cue has been perceived. Research was performed by McDaniel et al. (2004), in which participants completed tasks involving various delays and interruptions between cues and responses. It was demonstrated that correct performance suffered when there was a delay or interruption during a task. However, it was further shown that the use of reminders for participants eliminated the effects of the interruption task.