Prospective memory in children and chimpanzees

Prospective memory (PM) involves remembering to do something at a specific time in the future. Here, we investigate the beginnings of this ability in young children (3-year-olds; Homo sapiens) and chimpanzees (Pan troglodytes) using an analogous task. Subjects were given a choice between two toys (children) or two food items (chimpanzees). The selected item was delivered immediately, whereas the unselected item was hidden in an opaque container. After completing an ongoing quantity discrimination task, subjects could request the hidden item by asking for it (children) or by pointing to the container and identifying the item on a symbol board (chimpanzees). Children and chimpanzees showed evidence of prospective-like memory in this task, as evidenced by successful retrieval of the item at the end of the task, sometimes spontaneously with no prompting from the experimenter. These findings contribute to our understanding of PM from an ontogenetic and comparative perspective.     

Prospective memory performance across adolescence

In the present study, the authors explored age differences in event-based prospective memory (PM) across adolescence. The tasks consisted of an ongoing task (OT; i.e., personality questionnaire items, math problems) and an embedded prospective task that required participants to remember to make a special response whenever they encountered a PM cue (i.e., a negative word in the OT). The 341 participants (aged 13-22 years) revealed a significant main effect of age, which indicated better PM performance of young adults compared with teenagers. Moreover, when emphasizing the OT versus the PM task, teenagers' PM profited from PM emphasis more than did young adults' PM. The authors discuss the data in the context of limited executive capacity as a factor influencing cognitive development across adolescence.     

Prospective memory and frontal lobe function

The study sought to examine the role of frontal lobe functioning in focal prospective memory (PM) performance and its relation to PM deficit in older adults. PM and working memory (WM) differences were studied in younger aged (n = 21), older aged (n = 20), and frontal injury (n = 14) groups. An event-based focal PM task was employed and three measures of WM were administered. The younger aged group differed from the other two groups in showing significantly higher scores on PM and on one of the WM measures, but there were no differences at a statistically significant level between the older aged group and the frontal injury groups on any of the memory measures. There were, however, some differences in correlations with a WM measure between groups. It is concluded that there are similarities and differences in the deficits in PM between older adults and patients with frontal lobe injury on focal as well as nonfocal PM tasks.     

Prospective memory: When reminders fail

A frequent assumption in the area of prospective memory is that a reminder to do an activity in the future improves the likelihood of doing the activity. The results of four experiments indicated, however, that the most general version of this assumption is incorrect. Subjects were either reminded of a prospective memory task several times during a retention interval or not reminded of the prospective memory task. The most effective reminders referred both to the prospective memory target events and to the intended activity. Reminders that referred only to the target events did not improve prospective memory (relative to a no-reminder control). Reminders that referred only to the intended activity did improve prospective memory, but not to the level of reminders that referred both to the target events and to the intended activity. Instructions to imagine oneself performing the prospective memory task did not further improve prospective memory. Neither the delay between the prospective memory instructions and the prospective memory cover task nor the delay between a reminder and a prospective memory target event significantly influenced performance. The results, which are discussed in terms of theoretical and practical implications, support a new theory of prospective memory and suggest surprising conditions under which reminders fail to benefit prospective memory.     

Prospective memory in youth with perinatally-acquired HIV infection

Youth with perinatal HIV infection (PHIV) are at increased risk for neurocognitive impairment (NCI). Prospective memory (PM) is a complex neurocognitive function that has been shown to be impaired in adults with HIV disease and independently associated with poorer daily living skills, including medication nonadherence. The current study sought to determine the presence and extent of PM deficits in youth with PHIV. Participants included 173 youth with PHIV and 85 youth perinatally HIV-exposed but uninfected (PHEU), mean age 14.1 years, 75% black, 18% Hispanic. Among youth with PHIV, 26% had a past AIDS-defining condition (Centers for Disease Control and Prevention [CDC], Class C), 74% did not (non-C). Adjusted generalized estimating equation models were used to compare groups (PHIV/C, PHIV/non-C, and PHEU) on the Naturalistic Event-Based Prospective Memory Test (NEPT) and the Prospective Memory Assessment for Children & Youth (PROMACY). Secondarily, subgroups defined by HIV serostatus and global NCI were compared (PHIV/NCI, PHIV/non-NCI, PHEU). PHIV/C had significantly lower NEPT scores than PHEU, with decreases of 40% in mean scores, but did not differ from PHIV/non-C. PHIV/NCI had 11–32% lower PROMACY scores and 33% lower NEPT scores compared to PHIV/non-NCI (all p < .05); significantly, lower scores for PHIV/NCI versus PHEU also were observed for PROMACY and NEPT indices. Findings suggest a subset of youth with PHIV (those with a prior AIDS-defining diagnosis) is vulnerable to PM deficits. The extent to which PM deficits interfere with development and maintenance of independent living and health-related behaviors during transition to adulthood requires further study.     

Short-term flavour memory in the rat

In a series of experiments, rats were exposed twice to a flavour at times T1 and T2, and the second of these exposures was followed by toxicosis. The level of the subsequent aversion was viewed as an index of whether the flavour had been recognised as familiar at T2, with a familiar flavour accruing less aversiveness than an unfamiliar one. A flavour was recognised as familiar at time T2 after a long flavour-exposure at time T1 (Experiment Ia) when moderate (3·5 h) and long (27·5 h) T1-T2 intervals were employed but was so recognised after a brief exposure at T1 (Experiment Ib) only when a moderate T1-T2 interval was employed. The memorial processes underlying flavour recognition after a brief flavour exposure were assumed, therefore, to be transient. The remaining experiments employed a brief flavour exposure at T1 and moderate T1-T2 intervals in various attempts to disrupt flavour recognition. Recognition at T2, however, was not disrupted when one (Experiment II), or three (Experiment IV) distractor flavours were interpolated between the target flavour's presentations at T1 and T2. This failure was not due to the distractor having proactively interfered with the associability of the target flavour with illness at T2 (Experiment III). Further, recognition was not disrupted when the position of the target flavour's presentation at T1 was varied across a list of distractor flavours (Experiment V), nor when the similarity of the distractor and the target flavour was varied (Experiment VI). The results indicate that the processes subserving recognition after a brief presentation of that flavour, although transient, are resistant to interference and were discussed in terms of current theories of short-term memory in animals.     

Prospective memory, emotional valence and ageing

Emotional factors have been found to be an important influence on memory. The current study investigated the influence of emotional salience and age on a laboratory measure of prospective memory (PM); Virtual Week. Thirty young and 30 old adults completed Virtual Week, in which the emotional salience of the tasks at encoding was manipulated to be positive, negative or neutral in content. For event-based, but not time-based tasks, positivity enhancement in both age groups was seen, with a greater number of positive PM tasks being performed relative to neutral tasks. There was no negativity enhancement effect. Older adults showed generally poorer levels of PM, but they also demonstrated greater beneficial effects of positive valence compared to young. These effects of emotion on PM accuracy do not appear to reflect the retrospective component of the task as a different pattern of emotion effects was seen on the recall of PM content. Results indicate that older adults' difficulties in prospective remembering can be reduced where the tasks to be remembered are positive.     

Prospective memory performance in preschoolers: Inhibitory control matters

The present study focuses on prospective memory in preschoolers. We specifically investigated the effects of age, retrospective memory, and task interruption on prospective memory performance. In the first experiment, testing 60 children aged 3, 4 and 5 years with a prospective memory task that required active ongoing task interruption we obtained an age effect indicating better prospective memory performance for the two older cohorts. Varying retrospective memory load did influence prospective memory response time but did not affect prospective memory accuracy. However, retrospective memory performance showed an age effect and individual differences in retrospective memory ability were related to individual differences in prospective memory performance, even after partialling age. In the second study, we applied a prospective memory task that did not require active ongoing task interruption. Here, testing 62 children aged 3, 4 and 5 years we still found an age effect in retrospective memory but neither an effect of age nor retrospective memory on prospective memory performance. It is concluded that preschoolers even at the age of 3 years can perform prospective memory tasks to a certain extent. Moreover, while retrospective memory still seems to be somewhat related to prospective memory in preschoolers, inhibitory control required for ongoing task interruption seems to be an especially important factor influencing task performance in preschoolers.     

Prospective memory and aging: The effects of working memory and prospective memory task load

Abstract

A person's level of engagement in other actions may influence whether a prospective action is correctly performed. This study used a computerized prospective memory task in which participants remembered to perform an action when a specified background pattern appeared while they simultaneously performed a verbal working memory task. Amount of engagement in the working memory task was manipulated by increasing the number of words to be recalled. Prospective memory load was manipulated by varying the number of prospective targets. Older adults performed more poorly than younger adults on the prospective memory task under higher working memory load and also higher prospective load. Participants with lower working memory load performed better on the prospective task, regardless of age. There were no significant age differences in the absolute accuracy of performance postdictions (post experiment performance awareness). Age differences were also found with a second prospective memory task in which participants were told to write the day of the week (DOW) on the top of answer sheets for tasks performed later in the experiment. No significant correlations were observed between the two prospective memory tasks for either age group.     

Prospective memory in children: the effects of age and task interruption

Prospective memory (PM), remembering to carry out a task in the future, is highly relevant to children's everyday functioning, yet relatively little is known about it. For these reasons the effects of age and task interruption on PM were studied in 3 experiments. Children aged 4, 5, and 7 years were asked to name pictures in stacks of cards (the ongoing task) and to remember to do something when they saw a target picture (the PM task). Significant age differences were identified, but age explained only a small amount of variance. As predicted, children in the no-interruption condition performed significantly better than those who had to interrupt the ongoing activity in order to carry out the PM task. An additional finding was that no relation was detected between performance on prospective and retrospective memory tasks. Taken together, these findings provide support for current models of PM and identify ways to assist children's PM.     

Prospective memory in a language-trained chimpanzee (Pan troglodytes)

Prospective memory involves the encoding, retention, and implementation of an intended future action. Although humans show many forms of prospective memory, less is known about the future oriented processes of nonhuman animals, or their ability to use prospective memory. In this experiment, a chimpanzee named Panzee, who had learned to associate geometric forms called lexigrams with real-world referents, was given a prospective memory test. Panzee selected between two foods the one she wanted to receive more immediately. That food was scattered in an outdoor yard where she could forage for it. Also outdoors were lexigram tokens, one of which represented the food item that remained indoors throughout a 30 min period, and that could be obtained if Panzee brought in the token that matched that food item. After foraging for the selected food item, Panzee consistently remembered to retrieve and return the correct token when food was available indoors, whereas on control trials involving no indoor food she rarely returned a token. This indicated that Panzee encoded information relevant to the future action of token retrieval after extended delays for one type of food, even when a more immediately preferred food was available.     

Prospective memory for future intentions: Some comparisons with memory for past events

Abstract

Memory for future intentions was compared with memory for past activities by asking members of a film society to retrieve names of films they intended to see later on in a Season and films they had seen earlier. Memory for films that had been seen showed the usual recency effect, while retrieval of films to be seen showed an analogous proximity effect in that films to be seen sooner were more accessible. It was also found that recall of past films was inversely related to the total number of such films, but was unrelated to the average time interval since they were seen. In a similar fashion, retrievability of future films was inversely related to the total number of such films and was unrelated to when they were to be seen. There was a small but significant correlation between an individual's ability to retrieve the names of past and future films. Taken together, these correspondences suggest that similar empirical laws may govern the retrieval of stored information about past events and future intentions. Possible interpretations of the proximity effect and its theoretical implications are discussed.     

Prospective memory in young and older adults: the effects of ongoing-task load

Prospective memory involves remembering to perform intended actions in the future. Previous work with the multinomial model of event-based prospective memory indicated that adult age-related differences in prospective-memory performance were due to the prospective (not the retrospective) component of the task (Smith & Bayen, 2006 , Journal of Experimental Psychology: Learning, Memory, and Cognition, 32, 623). However, ongoing-task performance was also lower in older adults in that study. In the current study with young and older adults, the difficulty of the ongoing task was manipulated by varying the number of colors per trial to create easier and harder versions of the ongoing task for each age group. The easier version included 2 colors per trial for older adults and 4 colors for young adults. The harder version included 4 colors for older adults and 6 colors for young adults. By adjusting the ongoing-task difficulty, older adults were able to perform the ongoing task as well or better than the young adults. Analyses with the multinomial model revealed that making the ongoing task easier for older adults (or more difficult for young adults) did not eliminate age-related differences in prospective-memory performance and the underlying prospective component.     

Assessing absentmindedness: Prospective memory complaint and impairment in middle-aged adults

In two experiments, metamemorial differences between prospective and retrospective memory performance were examined. Participants in Experiment 1 were recruited through newspaper advertisements and comprised middle-aged women who experienced exceptional problems in prospective remembering. Experiment 2 involved self-reporters and nonreporters of retrospective memory problems, who were selected from a large population-based sample of middle-aged adults. In both experiments, memory performance was assessed by using a variety of tasks, including five retrospective memory tasks and three prospective memory tasks that varied in level of realism and retrieval support. In both experiments, there were selective differences in memory performance, so that participants who experienced (retrospective or prospective) memory problems showed impaired performance in prospective, but not in retrospective, memory tasks. These findings suggest that memory for future intentions provides a more sensitive task criterion than does memory for past events for assessing individual differences in self-reports of episodic memory problems. Task-specific differences in reliance on frontally mediated executive processes might underlie these differences.     

Prospective memory in early and established psychosis: An Indian perspective

Individuals affected by psychosis often have deficits in several neurocognitive functions. Prospective memory (PM), the ability to remember to do things, is crucial for activities of daily living, social and occupational functioning, but very few studies have attempted to examine this domain of functioning in people with psychosis, particularly in India. A total of 71 patients with psychosis, (both early and established psychosis), and 140 age, gender and education-matched healthy controls were assessed using the Positive and Negative Symptom Scale, Hospital Anxiety and Depression scale, and Addenbrooke's Cognitive Examination. PM was assessed using the Cambridge Prospective Memory Test and the Prospective and Retrospective Memory Questionnaire (PRMQ). Group differences were evaluated using Mann–Whitney U-tests. Significantly greater cognitive deficits, higher anxiety and depression were evident in the psychosis group compared with controls. The psychosis group performed significantly poorer on both time- and event-based tests in CAMPROMPT than controls. These differences remained when controlling for age, education, general cognitive functioning and mood. The subjective measure of PM (PRMQ) did not differentiate the two groups. The PM performance of early and established psychosis patients was similar. Comparisons with cross-cultural data (PRMQ UK norms and CAMPROMPT and PRMQ Chinese data) revealed important differences in PM performance. Individuals with psychosis have significant deficits in both time- and event-based PM. CAMPROMPT emerged as a more sensitive PM measure compared with PRMQ. Results from cross-cultural comparisons underscore the need for cultural contextualization of assessments.     

Recollection in an episodic-like memory task in the rat

Episodic memory in humans is the conscious recollection of a past event. Animal models of episodic-like memory assess the memory for "what"happened, "where" it happened, and either "when" it happened, or in "which" context it happened, although recollection on such tasks is often difficult to measure. Here we present the first evidence of successful recollection of a past event in a rat in a task which is easily performed, requires little training, and is easily adaptable for other commonly used laboratory species.     

Prospective memory across adolescence: the effects of age and cue focality

The present study examined the role of controlled attention in age differences in event-based prospective memory performance across adolescence. The researchers tested whether presenting the prospective memory cue in or out of focal awareness of the ongoing task (resulting in low versus high demands for controlled attention, respectively) might affect age-related prospective memory performance. In total, 119 Chinese participants ages 13 to 20 took part in this study (60 adolescents: age M = 13.26 years, SD = 0.50; 23 boys; 59 young adults: age M = 19.70 years, SD = 0.87; 19 men). Findings demonstrated a significant interaction, F(1, 114) = 6.41, p < .05. No effect of age on prospective memory performance was revealed when a focal cue was used (F < 1), whereas there was a reliable age effect between adolescents and young adults when nonfocal prospective memory cues were presented, F(1, 59) = 16.13, p < .01. This pattern of results suggests that the interplay of both available resources of controlled attention and working memory, along with specific task demands, may contribute to possible age differences in prospective memory performance across adolescence. Results are discussed in the context of the multiprocess theory of prospective memory.     

Spatial memory in the rat on a hierarchical maze

Rats were trained and tested on a hierarchical radial maze, which consisted of eight primary alleys radiating from a central platform and three secondary alleys which branched off the end of each primary alley. In four experiments, rats in groups 1, 2, and 3 were tested on maze configurations consisting of one, two, or three secondary alleys, respectively, at the end of each primary alley. In Experiment 1, each group was trained to collect food pellets in the secondary alleys. By the end of training, rats in each group collected all pellets efficiently, with little repetition of entrances into either primary or secondary alleys. In Experiments 2 and 3, tests were carried out which required retention of entrances into secondary alleys, as well as primary alleys. Two trials were run in succession, with selected secondary alleys blocked on trial 1 but open and baited with food on trial 2. Animals in groups 2 and 3 showed very accurate retention of blocked secondary alleys, regardless of variation in pattern and number of alleys blocked. A fourth experiment controlled for the possible use of food cues in Experiments 2 and 3 by rebaiting all secondary alleys between trials 1 and 2. Subjects continued to choose previously blocked alleys on trial 2, thus demonstrating that choice of blocked alleys was based on memory and not on a tendency to approach visual or olfactory food cues. Several findings of these experiments suggest that memories for primary and secondary alley choices are encoded and stored within separate memory systems. Possible coding mechanisms for these systems are discussed with reference to a process of cognitive mapping.