Prospective memory
Short answer
Prospective memory is the ability to remember to carry out an intended action in the future, such as calling someone back at three or picking up milk on the way home. Researchers split it into event-based tasks, triggered by a cue, and time-based tasks, triggered by checking the time. Lapses are common for everyone and do not, by themselves, indicate ADHD.
Most talk about memory is about the past: names, facts, what happened last week. Prospective memory faces the other way. It is remembering, at the right moment, to do the thing you planned to do.
Two flavors of remembering ahead
- Event-based: passing a pharmacy reminds you to pick up a prescription; seeing a coworker reminds you to return their charger.
- Time-based: joining a call at 2:00, taking a cake out after forty minutes, paying a bill before the end of the month.
Time-based tasks are often harder because nothing in the world taps you on the shoulder. You have to remember to check the clock yourself, which is one reason alarms and calendar alerts are so popular.
Ordinary moments where it slips
For example, someone might plan to post a letter on the way to work, walk straight past the mailbox while thinking about a meeting, and find the letter still in their bag that evening. The plan was formed. The memory of it simply did not fire when the cue arrived.
Busy days, interruptions, stress and fatigue all make these slips more likely. So does carrying many intentions at once without writing any of them down.
Questionnaires versus tasks
That distinction matters for self-report screeners in general. Answering questions about how often you forget appointments captures your view of your own life. It is valuable information, but it is not the same as a measured test of memory.
Links to screening and evaluation
Forgetting appointments and obligations is one of the everyday experiences that adults often bring up when they consider an ADHD evaluation. The ASRS v1.1 Screener asks how often certain experiences happened over six months; it does not test prospective memory. A clinician may ask how often these lapses occur, how long they have been happening, and what they have cost you.
What a lapse does not mean
Forgetting to do something later is one of the most universal human experiences. A lapse, or even a run of them during a hectic month, does not show ADHD or any memory disorder. Memory problems that are new, sudden or steadily getting worse deserve a prompt check with a healthcare provider, because that pattern has its own range of causes.
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Take the free six-question screenerFrequently asked questions
What is an example of prospective memory?
Remembering to call a friend back after work, take a pill with breakfast, or buy bread when you pass the bakery are all examples. Each involves remembering to act at a future moment.
Is forgetting to do things a sign of ADHD?
It can be part of what some people with ADHD describe, but it is very common in general, especially when busy, stressed or tired, so a lapse is not a sign of any particular condition.
Can a questionnaire measure prospective memory?
Not well, according to a 2022 review. Questionnaires may show how aware someone is of their difficulties, but the authors recommend pairing them with performance-based tasks.
Sources
Source check: 2026-10-28. No medical review has occurred.
Published 2026-10-28. Factual source check: ADHDFalcon editorial team, factual source check, 2026-10-28. No medical review has occurred.