Differences Between Prospective Memory And Retrospective
Updated December 19, 2018
Reviewer Wendy Boring-Bray, DBH, LPC
There are many different types of memory, some of which overlap with each other. In addition to the typical categories of sensory memory, short-term memory and long-term memory, there are many other subcategories of memory. Two of the distinct types of memory are prospective memory and retrospective memory.
These two types of memory are distinctly different but connected. Prospective memory does in part rely on retrospective memory characteristics to function. Both types of memory could be considered long-term memory, although short-term memory does play a role in prospective memory. These two types of memory differ in the areas of the brain that control their function, as well as how they are affected by aging and certain memory disorders.
What Is Prospective Memory
Prospective memory is memory of something that needs to be done in the future. This is the type of memory responsible for you remembering a planned event or intention at a future time. You use your prospective memory frequently throughout each day. It is one of the most functional and most used types of memory, and deficits in prospective memory can be especially devastating and frustrating.
Time Based Prospective Memory
Time based prospective memory is the type of memory you use when you want to do something at a specific time in the future. This type of prospective memory is usually the first to fail in memory disorders. It requires attention and recollection of a set time and is therefore more difficult to remember. Even people without memory deficits tend to test lower on time based prospective memory tests.
Event Based Prospective Memory
Event based prospective memory is the type of memory you use when you want to do something at a point in the future and you are reminded by an event. It can be a planned event, such as going to bed or eating a meal, or it can be an unplanned event, such as seeing the mailbox reminding you to send a letter. This is a much more common and easier to remember type of prospective memory.
Prospective Memory Examples
There are many examples of prospective memory that you use every day. Any time you have a planned event for the future, you are using your prospective memory. For most people, this is used quite frequently. Some examples of prospective memory include:
- Remembering to watch a sports game at 3 pm on the following Saturday
- Remember a doctor's appointment at a specific time on a specific day
- Remembering to mail a letter when you see the mailbox
- Remembering to brush your teeth before bed
- Remembering to take your medication with your meal
- Remembering to send an email while checking your email at work or school
- Remembering to perform a specific task at work that you put off for later
What Is Retrospective Memory
Retrospective memory is long-term memory of people, words and events that happened in the past. Retrospective memory makes up the largest part of your long-term memory. There are many different types of retrospective memory. When memory loss occurs, retrospective memory is usually hit hard. However, it can be less frustrating to lose your retrospective memory because, while it is frustrating, it does not affect your quality of life most of the time.
Episodic memory is memories of things you have done or that have happened to you throughout your life. Episodic memory includes autobiographical memory, such as remembering your wedding day. Episodic memory is also responsible for being able to remember what you ate for breakfast this morning or remembering opening a package you got in the mail.
Semantic memory is your memory of facts and knowledge that you have learned throughout your lifetime. When you remember sitting in class and your professor saying something specific about a topic, that is episodic memory. But when you don't recall necessarily the actual gaining of the information, just the information itself, that is semantic memory. For example, knowing all the state capitals is semantic memory.
Procedural memory is your memory of how to do things. It is automatic and does not require specific recall. Procedural memory is responsible for allowing you to remember how to walk, talk, run, skip, ride a bike, and drive a car. You don't really have to think about how to do these things because procedural memory steps in along with muscle memory and your body just does them.
Retrospective Memory Examples
There are many examples of retrospective memory of all types. Some of the most common examples of retrospective memory are:
- Remembering your wedding day
- Remembering the birth of a child
- Remembering that the capital of the United States is Washington DC and that it is different than Washington state
- Remembering how to ride a bike when you have not ridden a bike in many years
- Remembering how to drive a car
- Remembering how to eat with a fork and knife
Parts Of The Brain
One of the big differences between prospective memory and retrospective memory is that they use different parts of the brain to function. While there is some overlap, primarily these two types of memory use completely different parts of the brain to operate. Therefore, some brain injuries may affect prospective memory but not retrospective memory, and vice versa. It all depends on what part of the brain is affected.
Prospective memory makes use of the frontal lobe, the parietal lobe, and the limbic system to remember to perform future tasks. The frontal lobe is important because a certain amount of episodic and semantic memory is required to remember to perform the task and in the performing of the task itself.
Specifically, the prefrontal cortex is directly involved in remembering event-based prospective memory. It is responsible for holding the memory of the intention and repressing conflicting thoughts. Studies have found that the prefrontal cortex is not as important in time-based prospective memory.
The parietal lobe is responsible for recognizing the cues that remind you to do something in the future. This is especially true when the cues are visual or spatial. The parietal lobe is not as important for remembering time based prospective memory tasks, it is primarily used to remember event-based prospective memory tasks. When you remember to mail a letter because you saw the mailbox, that is an example of the parietal lobe at work.
The inferior parietal cortex is however used in time-based prospective memory. Studies have found that patients with damage to this part of the brain are unable to track time effectively to fulfill time-based prospective memory tasks.
The limbic system is made up of the more primitive parts of the brain, including the hippocampus, the thalamus, and the anterior and posterior cingulate. These parts of the brain are important for prospective memory because they allow you to create and remember intentions. The thalamus is activated when cues are recognized and acted upon during prospective memory tasks.
Different parts of the brain are responsible for retrospective memory. Retrospective memory also relies heavily on the hippocampus and the thalamus, as well as the prefrontal cortex. However, retrospective memory also relies on the medial temporal lobe which is important for the creation and retention of new memories. The amygdala is also highly important to retrospective memory.
Effects Of Aging
Aging has a normal effect of degrading the memory and can be assumed that aging plays a role in memory failure of both prospective and retrospective types. However, studies have found that this is not the case. When subjects young and old were tested for both prospective and retrospective memory, they found that age did not play a role in the ability to complete prospective memory tasks. On the other hand, aging did play a large role in the ability to remember things with retrospective memory.
Effects Of Alzheimer's
Alzheimer's research is constantly ongoing leading to more discovers about the disease every day. Alzheimer's disease affects a large percentage of the population and causes extreme memory loss over time as it worsens. Researchers have often tested to see what types of memory are affected by the disease.
One study found that prospective and retrospective memory were both affected by Alzheimer's and that the disease equally affects both types of memory. However, prospective memory loss is often the first type that is reported in Alzheimer's patients. The study speculated, based on caregiver surveys, that the reason prospective memory loss is the first complaint of Alzheimer's.
Ability To Retrain Memory
Retrospective memory loss is most often permanent, depending on the circumstances of the deficit. However, new studies have shown that prospective memory can be retrained and brought back to somewhat normal use in patients with Alzheimer's disease. The new study followed a group of Alzheimer's patients and trained them in different methods to remember and complete prospective memory tasks. Within one week all the subjects could complete the prospective memory tasks.
Getting Help With Memory
If you have noticed that you or a loved one are having difficulties with prospective or retrospective memory loss, you should seek out help as quickly as possible for testing, diagnosis and treatment. While retrospective memory loss to a degree is common with aging, prospective memory has not been shown to worsen with time. If you notice that you or your loved one are constantly having problems with prospective memory, you should get in touch with a professional to have your memory tested.
Your first step in getting help for prospective memory loss is to contact a psychologist. These professionals are able to test your memory and make sure that you do not have any significant deficits. If the memory test shows some memory loss, they can further help you on your path to diagnosis and treatment. The earlier treatment for certain conditions such as Alzheimer's begins, the longer you will remain high functioning. This means it is important not to put off memory testing.