Prospective memory
Encyclopedia
Prospective memory is a form of memory that involves remembering to perform a planned action or intention at the appropriate time. Prospective memory tasks are highly prevalent in daily life and range from relatively simple tasks 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 memory of people
, events and words that have been encountered in the past. Prospective memory and retrospective memory differ in the fact that retrospective memory emphasizes memory for events that have previously occurred, while prospective memory focuses on intended future events and is thus considered a form of memory for the future
. Retrospective memory involves the memory of what we know, containing informational content; prospective memory focuses on when to act, without focusing on informational content. There is some evidence demonstrating the role of retrospective memory in the proper performance of prospective memory, but this role seems to be relatively small.
cues you to remember that you need to return an overdue book
. Time-based prospective memory involves remembering to do an action at a particular point in time. For example, seeing that it is 10:00 PM acts as a cue for you to know that is it time to watch your favourite 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.
processes. These elements are used to differentiate between the wanted prospective memory intention and unwanted thoughts, in an attempt to keep focus on the goal and not the other options surrounding it. Retrospective memory is also used to remember specifically what intention is supposed to be performed in the future, and the monitoring process is needed to be able to remember to perform this action at the correct condition or time.
According to this theory, prospective memory should be enhanced when complete attention is given to the desired task than when attention is divided among multiple tasks. Research conducted by McDaniel et al. (1998) attempted to prove that prospective memory performance is better on focused tasks as opposed to those where attention is split. Subjects completed a prospective memory task in either a condition where full attention was given or a condition where attention was divided on other tasks. The results were consistent with the PAM theory, showing that participants’ prospective memory performance was better with full attention.
However, there is a lot of scepticism that the rather complex mechanisms of the PAM theory are required for all, sometimes mundane, prospective memory tasks. In research by Reese and Cherry (2002), participants formed an intention to act in the future, but were interrupted prior to acting on their intention when the cue was present. When participants were asked their thoughts at the moment of interruption, only 2% reported that they were thinking of the original intention. This demonstrated evidence against the PAM theory, that there is constant maintenance from the time of constructing the intention to acting upon it at the right circumstance.
Prospective memory cues will lead to spontaneous retrieval of an intention when at least one of three conditions is met: the cue and target action are highly associated with each other, the cue is salient, or the other processes performed during the period between cue and action of the prospective memory task direct attention to relevant cue features. Further research has found that although many aspects of prospective memory tasks are automatic, they do involve a small amount of processing. An experiment conducted by Einstein et al. (2005) found that some participants performed slower on a filler task when performing a prospective memory task at the same time. Even though some of the participants did not engage in active monitoring, they showed nearly the same rate of success on the task, demonstrating the use of multiple processes for prospective memory performance.
, declarative memory
, and retrospective memory, followed by supervisory executive functions. All of these are controlled by the frontal lobe
which is situated at the front of the cerebral hemisphere.
Studies using positron emission tomography (PET)
trace blood flow to the frontal lobe in participants completing prospective memory tasks involving remembering a planned action, while performing other tasks. During these procedures, sites of brain activation include the prefrontal cortex
, specifically the right dorsolateral, ventrolateral, and medial regions, as well as the median frontal lobe. The prefrontal cortex is responsible for holding the intention in consciousness and suppressing other internal thoughts. The median frontal lobe keeps attention focused on the planned action instead of the other tasks.
The prefrontal cortex is involved mainly in event-based as opposed to time-based prospective memory. Cheng et al. (2008) had participants with lesions in the prefrontal cortex perform event-based and time-based prospective memory tasks. They found that performance was impaired in the event-based tasks, which use event cues to trigger intentions, but not in the time-based tasks which use time cues to trigger intentions.
Other lesion studies have also shown the use of the frontal lobe in remembering and focusing on intentions. Burgess et al. (2000) studied patients with lesions to areas in the frontal lobe such as Brodmann’s area 10
, finding that these patients failed to follow instructions and switch attention during prospective memory tasks.
is typically involved in processing sensory information and is situated in the superior region of the brain.
For prospective memory, the parietal lobe is important for recognizing cues that trigger an intended action, especially when the cues are visual or spatial. The parietal lobe is also responsible for maintaining attention on the intended action and inhibiting other activities during performance. Studies using PET have shown that the parietal lobe is activated when participants engage in prospective memory tasks involving visual information such as remembering a series of numbers. Activation of the parietal lobe is also evident in studies using magnetoencephalography (MEG)
which traces electric activity of the brain.
Harrington et al. (1998) found that neural areas ranging from the inferior parietal cortex to the frontal gyri are involved in temporal monitoring during time-based prospective memory tasks. Patients with damage to these areas of the brain had difficulty judging duration and frequency of auditory tones that were presented. Keeping track of information over time is important for prospective memory, remembering intentions to perform in the future.
, which contains primitive brain structures relating to emotion and motivation, are involved in memory.
, or MEG to monitor brain activation. Finally, these tasks can be followed by questionnaires about prospective memory. Combining different assessments can confirm or deny experimental findings, making sure that conclusions about prospective memory are accurate. All tasks can assess individual stages of prospective memory such as the formation or execution of an intention, or access prospective memory as a whole by looking at overall performance.
negatively affects prospective memory. In research by Landsinger (2002), fifty-five undergraduates participated in a study comparing the effects of different stress and workload levels. Participants were assigned to one of four task groups (low workload-low stress, high workload-high stress, low workload-high stress, high workload- low stress) and all completed the same prospective memory task. Overall success and the time it took were compared. It was shown that both workload and stress can inhibit correct prospective memory performance, but the most detrimental effects occurred when both stress and workload are high. This finding is applicable to students as well as adults, because stress and large amounts of work are encountered in everyday student life and everyday job situations.
and healthy participant showed that the relatives performed significantly worse on time-based and event-based prospective memory tasks. Since schizophrenia has a heritable component, this suggested that genetics
may play a role in affecting prospective memory.
to more detrimental impairments such as early onset dementia
.
Toothpaste
Toothpaste is a paste or gel dentifrice used with a toothbrush as an accessory to clean and maintain the aesthetics and health of teeth. Toothpaste is used to promote oral hygiene: it serves as an abrasive that aids in removing the dental plaque and food from the teeth, assists in suppressing...
cap back on, remembering to reply to an email
Email
Electronic mail, commonly known as email or e-mail, is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. Some early email systems required that the author and the recipient both be online at the...
or remembering to return a rented movie. Examples of highly important situations include a patient remembering to take medication
Medication
A pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
or a pilot
Aviator
An aviator is a person who flies an aircraft. The first recorded use of the term was in 1887, as a variation of 'aviation', from the Latin avis , coined in 1863 by G. de la Landelle in Aviation Ou Navigation Aérienne...
remembering to perform specific safety procedures during a flight.
In contrast to prospective memory, retrospective memory
Retrospective memory
Retrospective memory refers to memory for people, words, and events encountered or experienced in the past. It includes all other types of memory including episodic, semantic and non-declarative. It can be either implicit or explicit...
involves memory of people
People
People is a plurality of human beings or other beings possessing enough qualities constituting personhood. It has two usages:* as the plural of person or a group of people People is a plurality of human beings or other beings possessing enough qualities constituting personhood. It has two usages:*...
, events and words that have been encountered in the past. Prospective memory and retrospective memory differ in the fact that retrospective memory emphasizes memory for events that have previously occurred, while prospective memory focuses on intended future events and is thus considered a form of memory for the future
Memory for the future
Memory for the future refers to the ability to use memory to picture and plan future events. It is a subcategory of "mental time travel" which Suddendorf and Corballis described to be the process that allows people to imagine both past and potential future events. Mental time travel into the future...
. Retrospective memory involves the memory of what we know, containing informational content; prospective memory focuses on when to act, without focusing on informational content. There is some evidence demonstrating the role of retrospective memory in the proper performance of prospective memory, but this role seems to be relatively small.
Event-based vs. Time-based prospective memory
There are two types of prospective memory: event-based and time-based prospective memory. Event-based prospective memory involves remembering to do a certain action when the specific circumstances are present. For example, driving past the local libraryLibrary
In a traditional sense, a library is a large collection of books, and can refer to the place in which the collection is housed. Today, the term can refer to any collection, including digital sources, resources, and services...
cues you to remember that you need to return an overdue book
Book
A book is a set or collection of written, printed, illustrated, or blank sheets, made of hot lava, paper, parchment, or other materials, usually fastened together to hinge at one side. A single sheet within a book is called a leaf or leaflet, and each side of a leaf is called a page...
. Time-based prospective memory involves remembering to do an action at a particular point in time. For example, seeing that it is 10:00 PM acts as a cue for you to know that is it time to watch your favourite 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.
Types of event-based prospective memory: Immediate-execute vs. delayed-execute
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.History and theoretical perspectives
There is great interest about the possible mechanisms and resources that underlie the workings of prospective memory.The Preparatory Attentional and Memory (PAM) Theory
The Preparatory Attentional and Memory (PAM) theory proposes two types of processes involved in successful prospective memory performance. The first component of this theory involves a monitoring process that begins when a person constructs an intention that is then maintained until it is performed. This monitoring component involves a capacity-consuming process, similar to those used when maintaining attention, because there is a need for the intention to be stored and maintained in memory. The second component involves the use of elements of retrospective memoryRetrospective memory
Retrospective memory refers to memory for people, words, and events encountered or experienced in the past. It includes all other types of memory including episodic, semantic and non-declarative. It can be either implicit or explicit...
processes. These elements are used to differentiate between the wanted prospective memory intention and unwanted thoughts, in an attempt to keep focus on the goal and not the other options surrounding it. Retrospective memory is also used to remember specifically what intention is supposed to be performed in the future, and the monitoring process is needed to be able to remember to perform this action at the correct condition or time.
According to this theory, prospective memory should be enhanced when complete attention is given to the desired task than when attention is divided among multiple tasks. Research conducted by McDaniel et al. (1998) attempted to prove that prospective memory performance is better on focused tasks as opposed to those where attention is split. Subjects completed a prospective memory task in either a condition where full attention was given or a condition where attention was divided on other tasks. The results were consistent with the PAM theory, showing that participants’ prospective memory performance was better with full attention.
However, there is a lot of scepticism that the rather complex mechanisms of the PAM theory are required for all, sometimes mundane, prospective memory tasks. In research by Reese and Cherry (2002), participants formed an intention to act in the future, but were interrupted prior to acting on their intention when the cue was present. When participants were asked their thoughts at the moment of interruption, only 2% reported that they were thinking of the original intention. This demonstrated evidence against the PAM theory, that there is constant maintenance from the time of constructing the intention to acting upon it at the right circumstance.
Reflexive-associative theory
Further research conducted by Einstein and McDaniel in 1990, found that subjects during prospective memory tasks reported that their intention often “popped” into mind, instead of being constantly monitored and consciously maintained. Another theory was proposed in 2000, called the reflexive-associative theory, which states that when people create an intention for a prospective memory task, they make an association between the target cue and the intended action. Later when the target cue occurs, the automatic associative-memory system triggers the retrieval of the intended action and brings it back into conscious awareness. Therefore, as long as the target cue occurs, the association previously made will initiate the retrieval of the intended action, regardless of whether the intention is in consciousness.Multi-process model
Another theory that has been used to explain the mechanisms of prospective memory is the multi-process model proposed by McDaniel and Einstein (2005). This theory states that prospective memory retrieval does not always need an active monitoring process but can occur spontaneously (i.e., the occurence of a cue can cause the intention to be retrieved, even when no preparatory attentional processes are engaged). Therefore, multiple processes can be used for successful prospective memory. Further, it was believed that it would be maladaptive to rely solely on active monitoring because it requires a lot of attentional resources. This may potentially interfere with other forms of processing that are required for different tasks during the retention interval.Prospective memory cues will lead to spontaneous retrieval of an intention when at least one of three conditions is met: the cue and target action are highly associated with each other, the cue is salient, or the other processes performed during the period between cue and action of the prospective memory task direct attention to relevant cue features. Further research has found that although many aspects of prospective memory tasks are automatic, they do involve a small amount of processing. An experiment conducted by Einstein et al. (2005) found that some participants performed slower on a filler task when performing a prospective memory task at the same time. Even though some of the participants did not engage in active monitoring, they showed nearly the same rate of success on the task, demonstrating the use of multiple processes for prospective memory performance.
Frontal lobe
As prospective memory involves remembering and fulfilling an intention, it requires episodic memoryEpisodic memory
Episodic memory is the memory of autobiographical events that can be explicitly stated. Semantic and episodic memory together make up the category of declarative memory, which is one of the two major divisions in memory...
, declarative memory
Declarative memory
Declarative memory is one of two types of long term human memory. It refers to memories which can be consciously recalled such as facts and knowledge. Its counterpart is known as non-declarative or Procedural memory, which refers to unconscious memories such as skills...
, and retrospective memory, followed by supervisory executive functions. All of these are controlled by the frontal lobe
Frontal lobe
The frontal lobe is an area in the brain of humans and other mammals, located at the front of each cerebral hemisphere and positioned anterior to the parietal lobe and superior and anterior to the temporal lobes...
which is situated at the front of the cerebral hemisphere.
Studies using positron emission tomography (PET)
Positron emission tomography
Positron emission tomography is nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide , which is introduced into the body on a...
trace blood flow to the frontal lobe in participants completing prospective memory tasks involving remembering a planned action, while performing other tasks. During these procedures, sites of brain activation include the prefrontal cortex
Prefrontal cortex
The prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas.This brain region has been implicated in planning complex cognitive behaviors, personality expression, decision making and moderating correct social behavior...
, specifically the right dorsolateral, ventrolateral, and medial regions, as well as the median frontal lobe. The prefrontal cortex is responsible for holding the intention in consciousness and suppressing other internal thoughts. The median frontal lobe keeps attention focused on the planned action instead of the other tasks.
The prefrontal cortex is involved mainly in event-based as opposed to time-based prospective memory. Cheng et al. (2008) had participants with lesions in the prefrontal cortex perform event-based and time-based prospective memory tasks. They found that performance was impaired in the event-based tasks, which use event cues to trigger intentions, but not in the time-based tasks which use time cues to trigger intentions.
Other lesion studies have also shown the use of the frontal lobe in remembering and focusing on intentions. Burgess et al. (2000) studied patients with lesions to areas in the frontal lobe such as Brodmann’s area 10
Brodmann area
A Brodmann area is a region of the cerebral cortex defined based on its cytoarchitectonics, or structure and organization of cells.-History:...
, finding that these patients failed to follow instructions and switch attention during prospective memory tasks.
Parietal lobe
The parietal lobeParietal lobe
The parietal lobe is a part of the Brain positioned above the occipital lobe and behind the frontal lobe.The parietal lobe integrates sensory information from different modalities, particularly determining spatial sense and navigation. For example, it comprises somatosensory cortex and the...
is typically involved in processing sensory information and is situated in the superior region of the brain.
For prospective memory, the parietal lobe is important for recognizing cues that trigger an intended action, especially when the cues are visual or spatial. The parietal lobe is also responsible for maintaining attention on the intended action and inhibiting other activities during performance. Studies using PET have shown that the parietal lobe is activated when participants engage in prospective memory tasks involving visual information such as remembering a series of numbers. Activation of the parietal lobe is also evident in studies using magnetoencephalography (MEG)
Magnetoencephalography
Magnetoencephalography is a technique for mapping brain activity by recording magnetic fields produced by electrical currents occurring naturally in the brain, using arrays of SQUIDs...
which traces electric activity of the brain.
Harrington et al. (1998) found that neural areas ranging from the inferior parietal cortex to the frontal gyri are involved in temporal monitoring during time-based prospective memory tasks. Patients with damage to these areas of the brain had difficulty judging duration and frequency of auditory tones that were presented. Keeping track of information over time is important for prospective memory, remembering intentions to perform in the future.
Limbic system
Much of the limbic systemLimbic system
The limbic system is a set of brain structures including the hippocampus, amygdala, anterior thalamic nuclei, septum, limbic cortex and fornix, which seemingly support a variety of functions including emotion, behavior, long term memory, and olfaction. The term "limbic" comes from the Latin...
, which contains primitive brain structures relating to emotion and motivation, are involved in memory.
- Hippocampus
-
- The hippocampusHippocampusThe hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
is found in the medial temporal lobe and plays an extensive role in memory retrieval. For prospective memory, the hippocampus is responsible for searching for the intended action among other memories. Studies using PET show activation in the hippocampus during event-based and time-based prospective memory tasks.
- The hippocampus
-
- Adda et al. (2008) assessed patients with episodic memory impairment due to epilepsy associated with mesial temporal sclerosisMesial temporal sclerosisMesial temporal sclerosis is a specific pattern of hippocampal neuron cell loss . There are 3 specific patterns of cell loss; Cell loss might involve sectors CA1 and CA4, CA4 alone, or CA1 to CA4 . Associated hippocampal atrophy and gliosis is common...
. Patients with this disorder have damage in the medial temporal lobe and hippocampus. Their performance on both event-based and time-based prospective memory tasks was significantly impaired. Their prospective memory performance was also worse than that of the control group after immediate, 30 minute, and seven day delays, but was especially noticeable after the long delays because the patients could not maintain information for long periods of time. Patients also suffered in their speed of processing, disregarding distractions, and episodic memory.
- Adda et al. (2008) assessed patients with episodic memory impairment due to epilepsy associated with mesial temporal sclerosis
-
- The same impairment in prospective memory is also seen in patients with lesions to the hippocampus. Damage to the left hippocampus has shown to have a worse effect on prospective memory than damage to the right hippocampus. While the hippocampus as a whole may be involved in prospective memory, the left side plays more of a dominant role. This shows the complexity of the brain and more research is needed to further understand the role of each section.
- Parahippocampal region
-
- The parahippocampal gyrusParahippocampal gyrusThe parahippocampal gyrus is a grey matter cortical region of the brain that surrounds the hippocampus. This region plays an important role in memory encoding and retrieval....
surrounds the hippocampus. Sensory information passes from cortical areas, through the parahippocampal gyrus to the hippocampus. The parahippocampal gyrus is activated during prospective memory tasks as shown by Kondo et al. (2010) who used diffusion tensor magnetic resonance imaging to trace the amount of water flow throughout the brain. This region is believed to play a role in recognizing cues that trigger the performance of intended actions.
- The parahippocampal gyrus
-
- Studies using PET have come to the same conclusions regarding the use of the parahippocampal gyrus for prospective memory. The parahippocampal gyrus is activated in paired-associate prospective memory tasks, in which participants must learn a pair of words and be able to remember one half of the word pair in later trials. It is suspected that the parahippocampal gyrus is additionally involved in monitoring the novelty of presented stimuli. If not monitored properly, new stimuli can be distracting during attempts to remember intentions for the future.
- Thalamus
-
- The thalamusThalamusThe thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...
is also located near the hippocampus. It relays sensory information among cortical areas of the brain, mediating the responses of cells and attentional demands. During successful prospective memory tasks, PET shows that the thalamus is activated when intention cues are presented and acted upon. No activity is shown in conditions where participants are expecting the cues to appear. Therefore, it is likely that the thalamus helps to maintain intentions and execute intentions only at the appropriate time.
- The thalamus
- Anterior and posterior cingulate
-
- The cingulate is another structure associated with the hippocampus. Its role in memory function is relaying information between the hippocampus and cortical areas. The anterior and posterior cingulate are involved in planning and creating intentions, which are initial stages in prospective memory. Lesions in the left anterior cingulate lead to failing to recall intentions, especially after a delay, which is needed for later stages of prospective memory.
Methods of testing prospective memory
Methods that test prospective memory require the distinction between retrospective memory, which is remembering information, and prospective memory, which is remembering information for the future. Prospective memory requires retrospective memory because one must remember the information itself in order to act in the future. For example, remembering to buy groceries after work (prospective memory) requires the ability to remember what type of groceries are needed (retrospective memory). While prospective memory and retrospective memory are connected, they are distinguishable. This makes it possible to separate these two processes during tests.Self-report
- Early self-report measures
-
- Many early measures of memory did not account for the distinction between prospective and retrospective memory. For example, the Cognitive Failures Questionnaire created by Broadbent et al. (1982) consists of 25 questions with only two relating to prospective memory. The Everyday Memory Questionnaire created by Sunderland et al. (1984) contains 18 questions with only three relating to prospective memory.
- The Prospective and Retrospective Memory Questionnaire (PRMQ)
-
- The Prospective and Retrospective Memory Questionnaire (PRMQ) was developed by Smith et al. (2000) to measure self-reports of prospective and retrospective memory in patients with Alzheimer’s disease. It is a questionnaire consisting of 16 items; in which participants rank how often memory failure occurs using a 5-point scale (Very Often, Quite Often, Sometimes, Rarely, and Never). The PRMQ equally assesses three variables: prospective and retrospective memory, short-term memoryShort-term memoryShort-term memory is the capacity for holding a small amount of information in mind in an active, readily available state for a short period of time. The duration of short-term memory is believed to be in the order of seconds. A commonly cited capacity is 7 ± 2 elements...
and long-term memoryLong-term memoryLong-term memory is memory in which associations among items are stored, as part of the theory of a dual-store memory model. According to the theory, long term memory differs structurally and functionally from working memory or short-term memory, which ostensibly stores items for only around 20–30...
, and self-cued and environmentally-cued memory.
- The Prospective and Retrospective Memory Questionnaire (PRMQ) was developed by Smith et al. (2000) to measure self-reports of prospective and retrospective memory in patients with Alzheimer’s disease. It is a questionnaire consisting of 16 items; in which participants rank how often memory failure occurs using a 5-point scale (Very Often, Quite Often, Sometimes, Rarely, and Never). The PRMQ equally assesses three variables: prospective and retrospective memory, short-term memory
-
- Since the PRMQ relies on self-report, it is limited by how participants interpret the questions, how participants perceive the strength of their own memory, and the willingness of participants to be truthful.
-
- The PRMQ has been proven to be a reliable and accurate method of testing memory. It has been evaluated against 10 other competing models and used for a range of different demographics including gender, education, economic status, age and country of origin.
-
- Many studies have used versions of the PRMQ since it was created. For example, the study by Crawford et al. (2003) used a PRMQ to test memory of a sample of the general adult population ranging in age from 17 to 94. Many questions are used to test all possible combinations of the different memory types assessed by the PRMQ. For example, questions such as “Do you decide to do something in a few minutes’ time and then forget to do it?” assessed prospective memory, short-term memory, and self-cued memory. Questions such as "Do you repeat the same story to the same person on different occasions?" assessed retrospective memory, long-term memory, and environmentally-cued memory.
Prospective memory tasks
Prospective memory tasks can be used in a variety of ways to assess prospective memory. Firstly, results from these tasks can directly assess prospective memory. Furthermore, these tasks can be performed while experimenters use PET, magnetic resonance imaging (MRI)Magnetic resonance imaging
Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
, or MEG to monitor brain activation. Finally, these tasks can be followed by questionnaires about prospective memory. Combining different assessments can confirm or deny experimental findings, making sure that conclusions about prospective memory are accurate. All tasks can assess individual stages of prospective memory such as the formation or execution of an intention, or access prospective memory as a whole by looking at overall performance.
- Event-based prospective memory tasks
-
- In event-based prospective memory tasks, participants are asked to remember to perform a task when cued by the appropriate information. There are numerous possible types of event-based tasks. For example, Raskin (2009) asked participants to sign their name when given a red pen, while Adda et al. (2008) asked participants to remember to request for a personal item to be returned at the end of the experiment.
- Time-based prospective memory tasks
-
- In time-based prospective memory tasks, participants are asked to remember to perform a task at a certain point in time. There are also numerous possible types of time-based tasks. For example, Cheng et al. (2008) asked participants to check a clock every five minutes during a written test, while Adda et al. (2008) asked participants to remind the experimenter to pay a bill on time.
- Standardized tests
-
- Standardized tests have been created to uniformly test prospective memory and can incorporate different event-based and time-based tasks at the same time. Experimenters can test prospective memory by having people perform tasks in order, perform tasks in order but with interruptions, and multitask.
-
- A typical standardized test may include the following five steps:
- 1) Participants are given instructions about an ongoing task and are allowed to practice.
- 2) Participants are given instructions for another task involving prospective memory.
- 3) Participants perform other activities during a delay between the formed intention and the presentation of the target cue.
- 4) Participants are reintroduced to the first ongoing task without being reminded of the prospective memory task.
- 5) The target cue is presented during the ongoing task, while the participants’ memory is assessed by how many times they remember to perform the intended action from the prospective memory task.
-
- Standardized tests such as the Cambridge Prospective Memory Test (CAMPROMT) or the Memory for Intentions Screening Test (MIST) are written tests in which participants complete event-based and time-based tasks while performing distractor tasks such as a word search. Participants are given verbal and written instructions and are allowed to use strategies such as note-taking in order to aid memory. Their performance is scored on a scale of 1 to 18, with 18 representing highest prospective memory performance.
Technological assessments
Technological assessments were created in order to more appropriately evaluate prospective memory by combining real life intentions with experimental control.- Virtual reality
-
- In virtual realityVirtual realityVirtual reality , also known as virtuality, is a term that applies to computer-simulated environments that can simulate physical presence in places in the real world, as well as in imaginary worlds...
, participants perform prospective memory tasks in a virtual world on a computer. Experimenters can create event-based tasks such as remembering to label boxes as fragile before moving or time-based tasks such as allowing a removal man to enter the house in five minutes. All tasks involve daily and other real life actions that rely on some aspects of prospective memory.
- In virtual reality
- Prospective Remembering Video Procedure (PRVP)
-
- In the Prospective Remembering Video Procedure (PRVP), participants are informed that they will receive tasks to complete while watching a video on a television screen. They are given a response sheet in order to record details of the tasks when the appropriate cues appear in the video. A distractor task is given at a certain point in order to test for prospective memory. Titov and Knight (2001) used a PRVP with a video consisting of a pedestrian walking through a shopping district and required participants to make decisions on whether to buy certain items as if they were the pedestrian. Shopping requires many prospective memory intentions such as remembering what items are needed and what items can be purchased another day.
Age
There is an increasing amount of research on the effect of age on prospective memory where typical studies compare groups of people from different ages. A study by Smith et al. (2010) comparing event-based prospective memory in schoolchildren (7–10 years old) and young adults found that adults had better memory performance. Another study by Kvavilashvili et al. (2009) comparing time-based prospective memory among young adults (18-30 year olds), young-old adults (60-75 year olds) and old-old adults (76-90 year olds) showed that young adults had better performance. Event-based prospective memory was further compared between young-old and old-old adults and findings were that young-old adults performed better than old-old adults. These studies suggested that there is continual improvement of prospective memory from childhood into young adulthood but that a decline begins in late adulthood.Stress
StressStress (biology)
Stress is a term in psychology and biology, borrowed from physics and engineering and first used in the biological context in the 1930s, which has in more recent decades become commonly used in popular parlance...
negatively affects prospective memory. In research by Landsinger (2002), fifty-five undergraduates participated in a study comparing the effects of different stress and workload levels. Participants were assigned to one of four task groups (low workload-low stress, high workload-high stress, low workload-high stress, high workload- low stress) and all completed the same prospective memory task. Overall success and the time it took were compared. It was shown that both workload and stress can inhibit correct prospective memory performance, but the most detrimental effects occurred when both stress and workload are high. This finding is applicable to students as well as adults, because stress and large amounts of work are encountered in everyday student life and everyday job situations.
Genetics
A study comparing prospective memory of non-psychotic first-degree relatives of patients with schizophreniaSchizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
and healthy participant showed that the relatives performed significantly worse on time-based and event-based prospective memory tasks. Since schizophrenia has a heritable component, this suggested that genetics
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
may play a role in affecting prospective memory.
Substance Use
- Smoking
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- Research shows mixed findings on the effect of smokingSmokingSmoking is a practice in which a substance, most commonly tobacco or cannabis, is burned and the smoke is tasted or inhaled. This is primarily practised as a route of administration for recreational drug use, as combustion releases the active substances in drugs such as nicotine and makes them...
on prospective memory, but more evidence is in favour of smoking diminishing prospective memory performance. Self-reported measures such as the Prospective and Retrospective Memory Questionnaire (PRMQ) have reported no difference between smokers and non-smokers; however, results from prospective memory tasks have suggested otherwise. Tasks are more objective as they eliminate subjective biases which can occur on the PRMQ. A study by Heffernan et al. (2010) suggested that persistent smoking is associated with prospective memory decrements and the impact of nicotineNicotineNicotine is an alkaloid found in the nightshade family of plants that constitutes approximately 0.6–3.0% of the dry weight of tobacco, with biosynthesis taking place in the roots and accumulation occurring in the leaves...
on long-term prospective memory may be dose dependent. Greater amounts of smoking lead to worse prospective memory performance.
- Research shows mixed findings on the effect of smoking
- Alcohol
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- Excessive drinkers self-reported more deficiencies in both short-term and long-term prospective memory on questions in the PRMQ. Chronic heavy alcohol users showed impaired performance on tasks including learning word lists, short- and long-term logical memory, general working memory, and abstract reasoning. Research has also accessed the effects of binge drinkingBinge drinkingBinge drinking or heavy episodic drinking is the modern epithet for drinking alcoholic beverages with the primary intention of becoming intoxicated by heavy consumption of alcohol over a short period of time. It is a kind of purposeful drinking style that is popular in several countries worldwide,...
on everyday prospective memory in adolescents. Binge drinkers and non-binge drinkers participated in two prospective memory sub-scales of the PRMQ. In addition to the questionnaires, the Prospective Remembering Video Procedure (PRVP) was used to test for an objective measure of prospective memory. It was shown that increasing the amount of alcohol consumed per week was correlated with poorer prospective memory performance on the PRVP, illustrating a damaging effect of excessive drinking upon everyday prospective memory for adolescents.
- Excessive drinkers self-reported more deficiencies in both short-term and long-term prospective memory on questions in the PRMQ. Chronic heavy alcohol users showed impaired performance on tasks including learning word lists, short- and long-term logical memory, general working memory, and abstract reasoning. Research has also accessed the effects of binge drinking
- Cannabis
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- CannabisCannabisCannabis is a genus of flowering plants that includes three putative species, Cannabis sativa, Cannabis indica, and Cannabis ruderalis. These three taxa are indigenous to Central Asia, and South Asia. Cannabis has long been used for fibre , for seed and seed oils, for medicinal purposes, and as a...
is a commonly used recreational drug derived from the plant Cannabis sativaCannabis sativaCannabis sativa is an annual herbaceous plant in the Cannabaceae family. Humans have cultivated this herb throughout recorded history as a source of industrial fibre, seed oil, food, recreation, spiritual enlightenment and medicine...
. The drug targets the central nervous systemCentral nervous systemThe central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
and is associated with cognitive impairments such as deficits in decision-makingDecision makingDecision making can be regarded as the mental processes resulting in the selection of a course of action among several alternative scenarios. Every decision making process produces a final choice. The output can be an action or an opinion of choice.- Overview :Human performance in decision terms...
, learning, and speed of processing. The most consistently reported deficit among users is related to memory performance. A study by Bartholomew et al. (2010) was conducted using the PRMQ and a video-based prospective memory task to test cannabis users and non-users. Cannabis users performed significantly worse on the both the PRMQ and the video-based prospective memory task, suggesting that cannabis negatively affects prospective memory.
- Cannabis
- Ecstasy and Metamphetamine
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- Ecstasy: Prospective memory performance is sensitive to regular and even moderate ecstasy use. Ecstasy users experience generalized difficulties with prospective memory.
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- MethamphetamineMethamphetamineMethamphetamine is a psychostimulant of the phenethylamine and amphetamine class of psychoactive drugs...
is a highly abused drug known commonly as “crystal meth” and chronic use is known to cause cognitive impairment. The same researchers studying the effects of ecstasy use on prospective memory have found parallel effects of methamphetamine. Impairments in prospective memory are still recognizable in former users who have been drug-free for an average of six years.
- Methamphetamine
Diseases and Disorders
Many diseases and disorders negatively affect prospective memory, as well as source memory, item recognition, and temporal order memory. The effects range from mild cognitive impairmentsMild cognitive impairment
Mild cognitive impairment is a brain-function syndrome involving the onset and evolution of cognitive impairments beyond those expected based on the age and education of the individual, but which are not significant enough to interfere with their daily activities...
to more detrimental impairments such as early onset dementia
Early-onset Alzheimer's disease
Early-onset Alzheimer's disease, also called early-onset Alzheimer's, or early-onset AD, is the term used for cases of Alzheimer's disease diagnosed before the age of 65. It is an uncommon form of Alzheimer's, accounting for only 5-10% of all Alzheimer's sufferers...
.
- Sickle cell disease
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- Sickle cell disease (SCD)Sickle-cell diseaseSickle-cell disease , or sickle-cell anaemia or drepanocytosis, is an autosomal recessive genetic blood disorder with overdominance, characterized by red blood cells that assume an abnormal, rigid, sickle shape. Sickling decreases the cells' flexibility and results in a risk of various...
is an autosomal recessive genetic blood disorder which leads to alterations in the shape of red blood cells. Not only can SCD impact the immune system, but it can lead to complications with memory. Children with SCD have shown impairments in event-based prospective memory. They may struggle with aspects of daily life that require prospective memory, such as forgetting to do homework even with a schoolbag nearby. More importantly, it is more difficult to manage the disease as they can forget about when to take medication or go to a doctor appointment. These effects can also persist into adulthood.
- Sickle cell disease (SCD)
- Parkinson's Disease
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- Patients with early Parkinson's diseaseParkinson's diseaseParkinson's disease is a degenerative disorder of the central nervous system...
suffer a large enough amount of prospective memory impairment to be affected in everyday life. These patients show impairment in the use of internal attentional strategies which are required for intention retrieval. Parkinson's disease leads to poorer performance on time-based but not event-based prospective memory tasks. For example, patients may forget to take medication at certain times of the day, but forgetting is less likely if they see the medicine bottle.
- Patients with early Parkinson's disease
- Schizophrenia
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- SchizophreniaSchizophreniaSchizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
has been shown to result in generalized prospective memory difficulties and is also associated with impairments in retrospective memory and executive functioning. Some studies have shown that retrospective memory impairment is not sufficient enough to produce the prospective memory impairment observed in schizophrenia patients. Therefore, schizophrenia leads to primary deficits in prospective memory, resulting in poor performance on both event-based and time-based prospective memory tasks. Managing schizophrenia includes the use of medication and therapy techniques such as cognitive behavioral therapy. Prospective memory is extremely important for these management techniques because forgetting medication or a therapy appointment can lead to the re-immergence of schizophrenic symptoms such as hallucinations, disorganized speech, and paranoia.
- Schizophrenia
- Multiple Sclerosis
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- Multiple SclerosisMultiple sclerosisMultiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...
is an inflammatory disorder that results in demyelination throughout the central nervous system. The relationship between the location of demyelination and cognitive impairment has not been consistently identified. Retrospective memory has been studied heavily and is known to be affected negatively by multiple sclerosis. However, a study by Rendell et al. (2006) showed that prospective memory failure is not entirely due to the failure of retrospective memory, and that multiple sclerosis can lead to generalized prospective memory difficulties.
- Multiple Sclerosis