Sebastian S. Horn

Age Effects in Emotional Prospective Memory: Cue Valence Differentially Affects the Prospective and Retrospective Component

While first studies suggested that emotional task material may enhance prospective memory performance in young and older adults, the extent and mechanisms of this effect are under debate. The authors explored possible differential effects of cue valence on the prospective and retrospective component of prospective memory in young and older adults. Forty-five young and 41 older adults performed a prospective memory task in which emotional valence of the prospective memory cue was manipulated (positive, negative, neutral). The multinomial model of event-based prospective memory was used to analyze effects of valence and age on the two prospective memory components separately. Results revealed an interaction indicating that age differences were smaller in both emotional valence conditions. For older adults positive cues improved the prospective component, while negative cues improved the retrospective component. No main effect of valence was found for younger adults on an overt accuracy measure, but model-based analyses showed that the retrospective component was enhanced in the positive compared with the negative cue condition. The study extends the literature in demonstrating that processes underlying emotional effects on prospective memory may differ depending on valence and age.

The Multinomial Model of Prospective Memory: Validity of Ongoing-Task Parameters

The objective of this research was to provide additional experimental validation of the multinomial processing tree (MPT) model of event-based prospective memory (Smith & Bayen, 2004). In particular, the parameters that measure trial-type detection in the ongoing task were examined. In three experiments with different response instructions, event-based prospective memory tasks were embedded in ongoing color-matching tasks. The results support the validity of the MPT model, that is, manipulations of ongoing-task difficulty affected the ongoing-task parameters of the MPT model, while leaving the estimates for the prospective and the retrospective components of prospective memory unaffected.

What Can the Diffusion Model Tell Us about Prospective Memory

Cognitive process models, such as Ratcliffs (1978) diffusion model, are useful tools for examining cost or interference effects in event-based prospective memory (PM). The diffusion model includes several parameters that provide insight into how and why ongoing-task performance may be affected by a PM task and is ideally suited to analyse performance because both reaction time and accuracy are taken into account. Separate analyses of these measures can easily yield misleading interpretations in cases of speed-accuracy trade-offs. The diffusion model allows us to measure possible criterion shifts and is thus an important methodological improvement over standard analyses. Performance in an ongoing lexical-decision task was analysed with the diffusion model. The results suggest that criterion shifts play an important role when a PM task is added, but do not fully explain the cost effect on reaction time.

Effects of sleep deprivation on prospective memory

Sleep deprivation reduces cognitive performance; however, its effects on prospective memory (remembering to perform intended actions) are unknown. One view suggests that effects of sleep deprivation are limited to tasks associated with prefrontal functioning. An alternative view suggests a global, unspecific effect on human cognition, which should affect a variety of cognitive tasks. We investigated the impact of sleep deprivation (25 hours of sleep deprivation vs. no sleep deprivation) on prospective-memory performance in more resource-demanding and less resource-demanding prospective-memory tasks. Performance was lower after sleep deprivation and with a more resource-demanding prospective-memory task, but these factors did not interact. These results support the view that sleep deprivation affects cognition more globally and demonstrate that sleep deprivation increases failures to carry out intended actions, which may have severe consequences in safety-critical situations.

Does frequency matter? ERP and behavioral correlates of monitoring for rare and frequent prospective memory targets

Behavioral and event-related potential (ERP) correlates of monitoring in an event-based prospective memory (PM) task were compared during blocks with rare versus frequent PM target presentations relative to an ongoing-task only condition. For both rare and frequent PM conditions, behavioral interference costs in terms of longer reaction times (RTs) were observed. Likewise, during both PM blocks a sustained ERP positivity with a frontal focus was identified on ongoing-task trials. While PM target identification and RT interference costs were larger during the PM-frequent relative to the PM-rare condition, the same sustained frontal positivity was observed during both PM blocks. These findings suggest that successful monitoring is associated with the adoption of a more general prospective retrieval mode, irrespective of target frequency. Moreover, preparatory attentional modulations directed at relevant target features played an important role for subsequent PM performance, as evident in larger P2 amplitudes during PM blocks.

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

ABSTRACT 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.

Modeling criterion shifts and target checking in prospective memory monitoring.

Event-based prospective memory (PM) involves remembering to perform intended actions after a delay. An important theoretical issue is whether and how people monitor the environment to execute an intended action when a target event occurs. Performing a PM task often increases the latencies in ongoing tasks. However, little is known about the reasons for this cost effect. This study uses diffusion model analysis to decompose monitoring processes in the PM paradigm. Across 4 experiments, performing a PM task increased latencies in an ongoing lexical decision task. A large portion of this effect was explained by consistent increases in boundary separation; additional increases in nondecision time emerged in a nonfocal PM task and explained variance in PM performance (Experiment 1), likely reflecting a target-checking strategy before and after the ongoing decision (Experiment 2). However, we found that possible target-checking strategies may depend on task characteristics. That is, instructional emphasis on the importance of ongoing decisions (Experiment 3) or the use of focal targets (Experiment 4) eliminated the contribution of nondecision time to the cost of PM, but left participants in a mode of increased cautiousness. The modeling thus sheds new light on the cost effect seen in many PM studies and suggests that people approach ongoing activities more cautiously when they need to remember an intended action.

Adult age differences in interference from a prospective- memory task: a diffusion model analysis

People often slow down their ongoing activities when they must remember an intended action, known as the cost or interference effect of prospective memory (PM). Only a few studies have examined adult age differences in PM interference, and the specific reasons underlying such differences are not well understood. The authors used a model-based approach to reveal processes underlying PM interference and age differences in these processes. Older and younger adults first performed a block of an ongoing lexical decision task alone. An embedded event-based PM task was added in a second block. Simultaneously accounting for the changes in response time distributions and error rates induced by the PM task, Ratcliff’s (Psychological Review 85:59–108, 1978) diffusion model was used to decompose the nonlinear combination of speed and accuracy into psychologically meaningful components. Remembering an intention not only reduced processing efficiency in both age groups, but also prolonged peripheral nondecision times and induced response cautiousness. Overall, the findings suggest that there are multiple, but qualitatively similar factors underlying PM task interference in both age groups.

The development of adaptive decision making: Recognition-based inference in children and adolescents

Judgments about objects in the world are often based on probabilistic information (or cues). A frugal judgment strategy that utilizes memory (i.e., the ability to discriminate between known and unknown objects) as a cue for inference is the recognition heuristic (RH). The usefulness of the RH depends on the structure of the environment, particularly the predictive power (validity) of recognition. Little is known about developmental differences in use of the RH. In this study, the authors examined (a) to what extent children and adolescents recruit the RH when making judgments, and (b) around what age adaptive use of the RH emerges. Primary schoolchildren (M = 9 years), younger adolescents (M = 12 years), and older adolescents (M = 17 years) made comparative judgments in task environments with either high or low recognition validity. Reliance on the RH was measured with a hierarchical multinomial model. Results indicated that primary schoolchildren already made systematic use of the RH. However, only older adolescents adaptively adjusted their strategy use between environments and were better able to discriminate between situations in which the RH led to correct versus incorrect inferences. These findings suggest that the use of simple heuristics does not progress unidirectionally across development but strongly depends on the task environment, in line with the perspective of ecological rationality. Moreover, adaptive heuristic inference seems to require experience and a developed base of domain knowledge. (PsycINFO Database Record

Within-person adaptivity in frugal judgments from memory

Humans can exploit recognition memory as a simple cue for judgment. The utility of recognition depends on the interplay with the environment, particularly on its predictive power (validity) in a domain. It is, therefore, an important question whether people are sensitive to differences in recognition validity between domains. Strategic, intra-individual changes in the reliance on recognition have not been investigated so far. The present study fills this gap by scrutinizing within-person changes in using a frugal strategy, the recognition heuristic (RH), across two task domains that differed in recognition validity. The results showed adaptive changes in the reliance on recognition between domains. However, these changes were neither associated with the individual recognition validities nor with corresponding changes in these validities. These findings support a domain-adaptivity explanation, suggesting that people have broader intuitions about the usefulness of recognition across different domains that are nonetheless sufficiently robust for adaptive decision making. The analysis of metacognitive confidence reports mirrored and extended these results. Like RH use, confidence ratings covaried with task domain, but not with individual recognition validities. The changes in confidence suggest that people may have metacognitive access to information about global differences between task domains, but not to individual cue validities.