Prospective Memory Performance Research Articles

Prospective memory performance in veterans with and without histories of mild traumatic brain injury: effect of the apolipoprotein E (APOE) ε4 genotype

ABSTRACT Objective Identifying factors that moderate cognitive outcomes following mild traumatic brain injury (mTBI) is crucial. Prospective memory (PM) is a cognitive domain of interest in mTBI recovery as it may be especially sensitive to TBI-related changes. Since studies show that genetic status – particularly possession of the apolipoprotein E (APOE) ε4 allele – can modify PM performance, we investigated associations between mTBI status and APOE-ε4 genotype on PM performance in a well-characterized sample of Veterans with neurotrauma histories. Methods 59 Veterans (mTBI = 33, Military Controls [MCs] = 26; age range: 24–50; average years post-injury = 10.41) underwent a structured clinical interview, neuropsychological assessment, and genotyping. The Memory for Intentions Test (MIST) measured PM across multiple subscales. ANCOVAs, adjusting for age and posttraumatic stress symptoms, tested the effects of mTBI status (mTBI vs. MC) and ε4 status (ε4+ vs. ε4−) on MIST scores. Results Veterans with mTBI history performed more poorly compared to MCs on the MIST 15-min delay (p=.002, ηp 2 =.160), Time Cue (p = .003, ηp 2 =.157), and PM Total (p = .016, ηp 2 =.102). Those with at least one copy of the ε4 allele performed more poorly compared to ε4- Veterans on the MIST 15-min delay (p = .011, ηp 2 =.113) and PM Total (p = .048, ηp 2 = .071). No significant interactions were observed between mTBI and APOE-ε4 status on MIST outcomes (ps>.25). Within the mTBI group, APOE-ε4+ Veterans performed worse than APOE-ε4− Veterans on the MIST 15-min delay subscale (p = .031, ηp 2 = .150). Conclusions mTBI history and APOE-ε4 genotype status were independently associated with worse PM performance compared to those without head injury histories or possession of the APOE-e4 genotype. Performance on the MIST 15-min delay was worse in Veterans with both risk factors (mTBI history and APOE-ε4 positivity). Findings suggest that genetic status may modify outcomes even in relatively young Veterans with mTBI histories. Future research examining longitudinal associations and links to neuroimaging and biomarker data are needed.

Effect of negative emotion on prospective memory and its different components

Prospective memory is an important and complex social cognitive ability, which is easily disturbed by negative emotions. According to the relationship between prospective memory cues and ongoing tasks, prospective memory can be divided into focal prospective memory and non-focal prospective memory. This study focuses on the influence of negative emotions on different types of prospective memory. In Experiment 1, 117 participants were recruited, using a 2 (emotion: negative, neutral) × 2 (cue focality: focal, non-focal) between-subjects design to initially explore whether negative emotions can interfere with the prospective memory of both focal cue and non-focal cue. The results show that negative emotions simultaneously reduce both types of prospective memory performance. At the same time, negative emotions occupy additional attention resources and impair the prospective component of prospective memory with non-focal cues. In Experiment 2, 64 participants were recruited to improve the difficulty of the retrospective component of prospective memory with non-focal cues, and the influence of negative emotions on different components of prospective memory with non-focal cues was further explored. The results show that negative emotions can impair both the prospective and retrospective components of prospective memory. In short, the results of this study indicate that negative emotion can impair prospective memory, and the impairment effect is not limited by the cue type of prospective memory. Meanwhile, negative emotion will occupy more attentional resources and simultaneously affect the prospective and retrospective components of prospective memory.

From attentional fluctuations to intentional fluctuations? Monitoring behavior and intraindividual variability in time-based prospective memory.

In sharp contrast to event-based prospective memory (PM), dynamics of (re)allocation of attention between the ongoing and PM tasks have been much less investigated in time-based PM tasks. We propose an in-depth examination of attention allocation in a time-based PM task by jointly analyzing multiple indicators of time-monitoring behavior, net and time-structured intraindividual variability (IIV) in ongoing-task reaction times (OT RTs), and task performance. Results from dynamic structural equation modeling in a lifespan sample of 198 adults (19-86 years) revealed that larger fluctuations in OT RTs (net IIV) predicted poorer OT performance, but fostered a more efficient pattern of time-monitoring behavior (i.e., checking a clock more frequently and strategically, and slowing OT RTs during the PM response window) that, in turn, enhanced PM. Conversely, greater inertia in OT RTs (time-structured IIV) led to fewer clock-checks and poorer PM performance. Focusing attention on time monitoring to enhance PM performance did not detrimentally affect OT accuracy. Instead, participants showed a speed-accuracy tradeoff to optimize both OT and PM accuracies by slowing their OT RTs during the PM response window. This study therefore shows that two concomitant aspects of IIV (net and time-structured IIV) not only predicted time-monitoring behavior, but also OT and PM accuracies differentially, hence advocating for the necessity to consider both aspects of IIV and time monitoring together to better understand attention allocation policies in time-based PM tasks. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

An evaluation of the moderating effects of routine and busyness on the relationship between prospective memory and everyday functioning in older persons with HIV disease

ABSTRACT Introduction People living with HIV (PLWH) often experience difficulties in everyday functioning, which can arise in part from deficits in the strategic/executive aspects of prospective memory (PM). Using Suchy’s Contextually Valid Executive Assessment (ConVExA) framework, this study sought to determine whether the contextual factors of busyness and routine moderate the relationship between the strategic/executive aspects of PM and everyday functioning in older PLWH. Methods Participants in this cross-sectional analysis were 145 PLWH aged 50 years and older who had completed the Martin and Park Environmental Demands (MPED) questionnaire of routine and busyness, the performance-based Cambridge Test of Prospective Memory, and self-report measures of activities of daily living (ADLs) and cognitive symptoms in daily life. Results Multiple regression analyses covarying for relevant comorbidities showed that higher levels of busyness – but not routine – were associated with more frequent cognitive symptoms in daily life. Neither busyness nor routine interacted with PM in association with cognitive symptoms. However, routine and a strategic/executive measure of PM interacted in predicting ADLs; specifically, the association between time-based PM and ADLs was stronger in persons with higher levels of routine in their daily lives. Parallel analyses with less executively-demanding event-based PM were null and small. Conclusions Overall, findings provided mixed – and unexpected – evidence for the associations between contextual factors (i.e. routine and busyness), everyday functioning, and PM in this sample of older adults with HIV disease. Results and clinical implications are interpreted and discussed in the framework of the ConVExA model.

Efficacy of Digital and Non-Digital Compensatory Strategies in Supporting Prospective Memory Task Completion among Community-Dwelling Mid-Life and Older Adults.

Compensatory strategies can be used to help mid-life and older adults successfully manage instrumental activities of daily living that rely upon prospective memory. This study compared the quality of digital and non-digital compensatory strategies in supporting accurate completion of naturalistic, real-world prospective memory tasks. Participants included 70 community-dwelling mid-life and older adults. In this cross-sectional study, participants were tested remotely via Zoom in their homes. They were tasked with completing four real-world prospective memory tasks and encouraged to use their typical compensatory strategies. Utilized strategies were categorized, counted, and assigned quality scores (rating of thoroughness and utility), and prospective memory performance was coded. Participants who used any digital strategies utilized significantly more (ηp2 = .17) and better quality (ηp2 = .12) strategies than participants who did not use any digital strategies. However, the groups demonstrated equivalent prospective memory performance (ηp2 = .006). Within the digital group, participants' digital and non-digital strategies were of similar quality (d = .14) and resulted in similar prospective memory task accuracy (d = .01). Digital and non-digital strategies led to similar performance on naturalistic prospective memory tasks. Findings suggest that many different types of strategies can provide adequate prospective memory support to healthy mid-life and older adults. To inform development of compensatory strategy interventions, future studies should explore other factors that lead to successful prospective memory, such as the specific strategy type and task type match, across the continuum of cognitive impairment.

Meta-prospective memory accuracy in older adults with and without suspected Mild Cognitive Impairment (sMCI)

This study examined if the relationship between generalized and task-specific appraisals of prospective memory (PM) and actual PM performance (i.e., meta-PM accuracy) differed between healthy and suspected Mild Cognitive Impairment (sMCI) older adults. Older adults recruited included 50 healthy and 31 sMCI participants from the community and an outpatient neuropsychology clinic. Data collected consisted of self-reported appraisals and task-specific predictions/postdictions of PM performance, objective PM performance, and executive functioning (EF). The sMCI group had significantly lower scores on objective PM and EF measures related to simple and complex task-switching. Moreover, sMCI participants displayed lower task-specific meta-PM accuracy in the direction of overconfidence, but they displayed relatively equivalent generalized meta-PM accuracy when compared to the healthy group. Notably, the sMCI group’s task-specific inaccuracies became non-significant in relation to the healthy group on the final long-term PM tasks after exposure to metacognitive reflection on the first two PM tasks. Despite lower scores on EF measures, EF performance did not explain task-specific meta-PM differences between groups beyond neurocognitive status. Based on these data, sMCI patients may be better assisted by metacognitive calibration strategies, EF protocols, and the implementation of general compensatory memory strategies as targets for early intervention and prevention of neurocognitive decline.

Rumination, but not mood, predicts prospective memory performance: novel insights from a derived measure of trait rumination

ABSTRACT Prospective memory (PM) is the accurate execution of an intention in the future. PM may be negatively impacted by negative affect, but the underlying mechanisms remain unclear. Rumination may increase the frequency of task-irrelevant thoughts, which deplete attentional capacity and reduce performance. To date, no studies have examined state and trait rumination on an online measure of PM. The present study examined the effects of state and trait rumination on an event-based, focal PM task embedded within a one-back task over multiple sessions. 95 non-depressed adults (18–53 years) completed measures of state/trait rumination, mood, and PM on at least two occasions. Using multi-level modelling, we found that a derived measure of trait rumination, but not an established trait rumination survey, nor negative mood, predicted poorer PM accuracy. These novel findings demonstrate that trait rumination may partially underlie the association between negative affect & PM in a non-clinical sample, and highlight the potential of online methods to study PM.

The Effect of Time Monitoring on the Development of Time-Based Prospective Memory among Children Aged 7-11 Years Old.

Time-based prospective memory (TBPM) refers to the ability of an individual to successfully execute an expected plan in the future at a certain time point or after a definite period of time. This study investigated the potential developmental mechanism of school-age children's TBPM ability from the perspective of time monitoring. Experiment 1 used a between-subjects design of three ages (7, 9, 11) × two TBPM types (time point, time period) to investigate the trends and characteristics of two types of TBPM in children aged 7-11 years old. Experiment 2 used a between-subjects design of three ages (7, 9, 11) × two monitoring conditions (free monitoring, fixed monitoring) to investigate differences in two types of TBPM and monitoring behavior among school-age children under different monitoring conditions. These results showed that the age effect of TBPM was affected by the type of prospective memory (PM) and that time-point PM performance was significantly better than time-period PM performance among school-age children. These findings indicate that clear and definite external cues are helpful for school-age children in performing TBPM tasks. Moreover, there were significant differences found in the TBPM performance of school-age children under different time monitoring conditions. The performance of older children was significantly better than that of younger children. This indicates that older children can better allocate their attentional resources and use time monitoring strategies to improve their performance in PM tasks. Accordingly, this study showed that the TBPM ability of 7- to 11-year-old children is in continuous development and that the time monitoring behavior in the TBPM task is affected by task type and monitoring conditions.

Differences in time-based prospective memory between field-independent and field-dependent cognitive styles under different time monitoring conditions

Time-based prospective memory involves tasks that must be executed at a specific time in the future. Individuals can complete time-based prospective memory tasks using internal attention and external attention. Field-independent and field-dependent cognitive styles are two of the most well-known cognitive styles. Field-independent individuals and field-dependent individuals prefer to use internal reference and external reference to process information, respectively, which implies that there may be differences in the processing mechanisms of the two cognitive styles when performing time-based prospective memory tasks. This study focused on differences in time-based prospective memory performance and processing mechanisms between field-independent and field-dependent cognitive style individuals under different time monitoring conditions. A total of 119 participants were recruited through an Embedded Figure Test and divided into four groups. Time monitoring conditions consisted of a free monitoring condition and a restricted monitoring condition. Participants in the restricted monitoring condition could only press the space bar once, whereas those in the free monitoring condition could check the time at any time and without restrictions. The results of the study showed that field-independent individuals expend less internal and external attention than field-dependent individuals. However, field-independent individuals have higher attention effectiveness and employ more strategies for processing time information. Field-independent individuals were also found to have better time-based prospective memory performance under both time monitoring conditions. Field-dependent individuals did check the time more often under the free monitoring condition, but their time-based prospective memory performance did not benefit from more external attention because although they expended more external attention, they did so less effectively. In short, compared with field-dependent individuals, field-independent individuals had better time-based prospective memory performance under both time monitoring conditions because they have higher attention effectiveness and adopt more strategies for the processing of time information.

Effect of multiple sclerosis and aging on prospective memory using the ecological test of prospective memory.

Prospective memory (PM) is the ability to remember to produce an action at a specific moment in the future signaled by the occurrence of a specific event (event-based [EB] condition), a time or a time interval (time-based [TB] condition). Detection of the appropriate moment corresponds to the prospective component, while production of the appropriate action corresponds to the retrospective component. Although PM difficulties have been reported in healthy aging and in association with multiple sclerosis (MS), PM has not been examined in older persons with MS (PwMS). The main objective of this study was to investigate whether the decline in PM performance with advancing age is influenced by the presence of MS. This study also aimed to clarify the type of PM impairment (prospective vs. retrospective component in TB and EB conditions) in MS as a function of age. A total of 80 participants were recruited and separated into four groups: older PwMS (n = 20), younger PwMS (n = 20), older controls (n = 20), and younger controls (n = 20). PM and its components were measured using the Test Ecologique de Mémoire Prospective (TEMP), an experimental ecological tool using naturalistic stimuli developed by our laboratory that has been validated in previous studies. On the TEMP total score, a two-way analysis of covariance showed a main effect of age, a main effect of the presence of MS, as well as a significant Age × Disease interaction. Direct comparison between EB and TB conditions revealed that for the prospective component, only older PwMS had more difficulty in the TB than in the EB condition, whereas the retrospective component score was significantly lower in the TB than in the EB condition in all groups except in younger controls. The TEMP revealed a marked impairment in PM in older PwMS compared to older controls and young PwMS. This impairment was particularly evident on the prospective component in the TB condition. Retrospective difficulties noted in the TB condition in all, but younger controls reflect the arbitrary nature of the cue-action link that is particularly sensitive to episodic memory difficulties often observed in aging and MS. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The effect of verbal praise on prospective memory.

Verbal praise is often used to improve prospective memory performance in daily life. According to the motivation cognitive model, the promotional effect of verbal praise on prospective memory may depend largely on redeploying attentional resources, so its promotional effect is likely to be influenced by attention. Two groups of college students (n = 128, n = 117) participated in two experimental studies that examined this hypothesis. Experiment 1 manipulated attention load by changing the difficulty of the ongoing tasks to focus on the effect of verbal praise on prospective memory under different attention load conditions. The results showed that verbal praise promoted prospective memory performance under both attentional load conditions (low, high), but verbal praise mainly promoted the prospective component when the attentional load was low, meanwhile, verbal praise mainly promoted the retrospective component when the attention load was high. Experiment 2 altered the dependence of prospective memory tasks on attentional resources by manipulating the cue focality, further exploring the promotional effect of verbal praise on prospective memory with different types of cues under the low attention load condition. The results showed that verbal praise only promoted prospective memory when non-focal cues were used. The results of this study partially verified the motivation cognitive model.

How do the cognitive processes matter in the event-based preschoolers' prospective memory?

Prospective memory (PM) is the ability to remember to perform an intended action at a specific future moment. The current study examined the impact of age, task focality, and cue salience on PM in children aged 2 to 6 years, based on the multiprocess theory of PM and the executive framework of PM development. Additionally, the study explored the relationship between various cognitive abilities and their association with PM performance. A total of 224 preschool-aged children, aged 2-6, engaged in event-based PM tasks with varying cognitive demands. The tasks were either focal or nonfocal, with salient or nonsalient cues. Additionally, individual differences in cognitive abilities were measured. The results support previous indications that even very young children can successfully complete event-based PM tasks. The accuracy of PM display improved with age, especially between the ages of 3 and 4. Better performance was observed in focal PM tasks compared to nonfocal PM tasks. Additionally, preschoolers' PM performance correlated with various cognitive abilities, including fluid intelligence, retrospective memory, inhibitory control, working memory, and language ability. These correlations varied depending on the child's age and the task's nature. For both focal and nonfocal PM tasks, cognitive abilities partially mediated the relationship between age and PM performance. In summary, this study comprehensively explores the specific roles played by age and fundamental cognitive abilities in event-based PM performance among preschool-aged children.

Relationship between Working Memory, Retrospective Memory and Strategic Monitoring with Prospective Memory Performance

Working memory is one of the significant factors that can influence prospective memory. Prospective memory inherently encompasses elements of retrospective memory, and strategic monitoring also affects performance. Therefore, the study investigates the relationship between strategic monitoring, retrospective memory, working memory, and prospective memory. The study involved 120 participants (60 females and 60 males). The Beck Depression Inventory, n-Back tasks, and Virtual Week tasks were administered to the participants. According to the findings, working memory performance predicts prospective memory (β= .30; p

A Parent-Report Diary Study of Young Children’s Prospective Memory Successes and Failures

ABSTRACT Although laboratory studies have examined the development of children’s prospective memory (PM) and the factors that influence its performance, much less is known about children’s PM performance and development in their everyday life. The current study used an online parent diary report approach to examine American 2- to 6-year-olds’ PM successes and failures. In an initial session, 206 parents completed a series of questionnaires on their child’s memory and cognition. For the next four days, parents reported instances of PM successes and failures and answered questions about a number of task factors (task motivation, importance to the parent and child, who assigned the PM task, task typicality, and parental assistance). We found that: (1) parents reported children as young as 2 years old had PM successes in daily life and there were no age differences in the number of reported PM successes and failures, (2) parents reported more PM successes than failures, and (3) several factors influenced the likelihood of children’s success in everyday PM tasks, including child motivation and task importance to parents, whereas task typicality and parental assistance were related to PM failure. Finally, we explored the domains of PM successes and failures as well as the type of assistance that parents provided. These results are discussed in relation to past findings of children’s PM in laboratory and naturalistic settings. Parent diary-report methodology is a feasible and efficient alternative to naturalistic laboratory tasks to examine young children’s PM in everyday life.

Emotion and prospective memory: effects of emotional targets and contexts.

Event-based prospective memory (PM) refers to the ability to remember to perform a delayed and intended action when an event is encountered in the future. Whether emotional targets promote PM performance is still controversial. The reason for these inconsistent findings may be related to the degree of target arousal and context valence (the valence of ongoing task trials) in the previous studies. This study aimed to investigate the separate and combined effects of target valence, arousal, and context valence on event-based PM through two experiments. The results showed that the participants were faster and more accurate in responding to positive, negative, and high-arousal PM targets. Interestingly, an interaction effect of target valence, arousal, and context valence was observed, implying that their individual effects on PM performance cannot be understood in isolation. These findings demonstrate that positive, negative, and high-arousal PM targets can enhance PM performance. In addition, the results provided support for both the emotion enhancement account and the emotion-saliency account, depending upon whether the valence of the PM target matched or did not match the valence of the context. Moreover, context valence can modulate the effect of arousal on PM across different target valences.

Exploring the Relationship between Emotional Valence and Prospective Memory Metamemory in Younger and Older Adults

Prospective memory (PM) plays a crucial role in daily autonomy. Metamemory and emotional valence have both been shown to influence PM performance in younger and older adults. However, when considered together, the relationship between emotional valence, metamemory, and PM has not been examined yet, especially whether metamemory PM representations develop with task experience (i.e., before versus after performing a task). We collected data from 25 younger and 19 older adults using an event-based PM task with emotional cues (positive, negative, or neutral). Results revealed that younger adults’ predictions underestimated performance for neutral and negative cues. After performing the task, they showed more accurate representations for neutral cues, indicating that they monitored their representations. Older adults’ predictions overestimated performance for negative PM cues, and they did not modify representations after performing the task. Thus, we do not find evidence that older adults are able to coherently monitor their PM representations. These findings highlight the importance of understanding PM representations, especially in older adults, as they may lead to less strategy use and more impaired PM performance in negative everyday situations.

The role of offloading intentions on future-oriented thinking.

Offloading (e.g., using Google calendar reminders) has been shown to improve prospective memory (PM). One unstudied aspect of PM offloading is whether having reminders reduces our future-oriented thinking about PM intentions in contexts in which the intention cannot be fulfilled. In the current study, participants were given two blocks of an ongoing lexical decision task. Prior to beginning the task, participants formed an intention to make a special response to PM targets only in block 2. Participants in the reminder condition had the PM intention displayed at the top of the screen in block 2, whereas those in the no-reminder condition did not. To assess activation of the intention out of context, PM lures (Experiment 1) or thought probes (Experiments 2 and 3) were presented in block 1. Results showed that reminders improved PM performance in block 2 but did not reduce lure interference or PM-related thoughts in block 1. These findings suggest that offloaded memory representations remain as activated and accessible as non-offloaded representations outside the context in which intentions can be fulfilled.

The breadth of animacy in memory: New evidence from prospective memory.

Studies using retrospective memory tasks have revealed that animates/living beings are better remembered than are inanimates/nonliving things (the animacy effect). However, considering that memory is foremost future oriented, we hypothesized that the animacy effect would also occur in prospective memory (i.e., memory for future intentions). Using standard prospective memory (PM) procedures, we explored this hypothesis by manipulating the animacy status of the PM targets. Study 1a reports data collected from an American sample; these results were then replicated with a Portuguese sample (Study 1b). Study 2 employed a new procedure, and data were collected from a broader English-speaking sample. In these three studies, animate (vs. inanimate) targets consistently led to a better PM performance, revealing, for the first time, that the animacy advantage extends to PM. These results strengthen the adaptive approach to memory and stress the need to consider animacy as an important variable in memory studies.

Loneliness during the post-confinement period: The significance of social living conditions for stress biomarkers and memory

In the aftermath of the COVID-19 lockdown, concerns about the impact of loneliness and reduced social interactions on mental health have arisen. This study explored the repercussions of post-lockdown social restrictions across psychological (loneliness, perceived stress, and depressive symptoms), biological (hair cortisol and cardiovascular activity), and cognitive dimensions (subjective memory complaints and working, declarative, and prospective memory), with a specific emphasis on perceived loneliness and the living situation. The study included 45 students: 23 (mean age = 25.69 years) in the Alone Group (AG), who experienced significant family changes and international relocation, and 22 (mean age = 25.50 years) in the Not Alone Group (NAG), who maintained their nuclear family and did not move from their home country. We assessed heart rate variability (HRV) before, during, and after immediate memory evaluations using time-domain (the square root of the mean, RMSSD) measures. The analysis revealed no significant group differences in telematic contact with family and friends, perceived stress, or depression. However, the AG participants reported fewer face-to-face interactions and greater perceived loneliness compared to the NAG. Additionally, the AG group exhibited slightly higher hair cortisol levels and worse working memory (WM) and prospective memory (PM) performance. Importantly, no significant associations were observed between memory outcomes and stress biomarkers. However, a significant interaction effect of loneliness in the relationship between hair cortisol levels and PM was found. That is, hair cortisol concentrations were negatively related to PM when participants perceived high and moderate loneliness. This interaction was absent in the working and declarative memory domains. In summary, these findings underscore the intricate interplay between loneliness, cortisol, and memory, emphasizing the need for comprehensive research on the complex mechanisms governing these multifaceted relationships.

Time-Based and Event-Based Prospective Memory in Mild Cognitive Impairment and Alzheimer's Disease Patients: A Systematic Review and Meta-analysis.

Prospective memory (PM) is the ability to remember to perform planned actions in a future moment and it is of fundamental importance for an independent and autonomous lifestyle from development to late adulthood. Deficits in episodic memory and executive functions, which are involved in PM are characteristic features of mild cognitive impairment (MCI) and Alzheimer's disease (AD). Considering that the number of older adults is drastically increasing over the next decades, it is of great interest to understand how PM decline in healthy older adults and patients with different degree of cognitive decline. The present meta-analysis included 46 studies investigating PM performance in AD patients (17 studies) and people with MCI (24 studies); 5 studies included both clinical conditions in the same article. The 46 studies contributed a total of 63 independent samples and 129 effect sizes from 4668 participants (2115 patients and 2553 controls). Unlike previous reviews of the literature, our results with a larger and updated sample of studies confirmed lower PM abilities in AD compared to MCI and controls, although we did not observe conclusive differences between event-based and time-based PM in patients. Surprisingly, PM deficits shown by MCI and AD patients have decreased across years, in parallel to a reduction of the evidence of publication bias and an increase in the number of observations per task. We propose the use of more reliable research designs as one plausible explanation for the reduction of PM impairments.