B. Hunter Ball

Processing Fluency Mediates the Influence of Perceptual Information on Monitoring Learning of Educationally Relevant Materials

Previous research has shown that perceptual characteristics of stimuli inaccurately bias assessments of perceived memorability. However, little research has investigated how perceptual information using real-world study materials affects study time allocation and assessments of future memory performance. In the current study, participants studied a series of terms and their corresponding definitions that varied on perceptual dimensions commonly used in educational material. When participants were allowed to control their own study time, font bolding (Experiment 1) and font size (Experiment 2), but not borders surrounding the text (Experiment 3), influenced judgments of learning despite having no effect on actual memory performance. Items that were processed more easily (as evidenced by study duration) consistently resulted in metacognitive monitoring biases, suggesting that encoding fluency may lead to inaccurate beliefs about ones own learning and future memory performance in educational settings.

The effects of prior knowledge on the encoding of episodic contextual details

A positive relationship between prior knowledge and item memory is a consistent finding in the literature. In the present study, we sought to determine whether this relationship extends to episodic details that are present at the time of encoding, namely source memory. Using a novel experimental design, we were able to show both between- and within-subjects effects of prior knowledge on source memory. Specifically, the results revealed that the degree of prior knowledge positively predicted memory for source specifying contextual details. In addition, by including two conditions in which attention was divided either at encoding or retrieval, we were able to show that prior knowledge influences memory by affecting encoding processes. Overall, the data suggest that a priori knowledge within a specific domain allows attentional resources to be allocated toward the encoding of contextual details.

Uncovering continuous and transient monitoring profiles in event-based prospective memory

The present study implemented response time distribution modeling to better characterize context-specific attention dynamics underlying task interference due to possessing a prospective memory intention. During a three-phase paradigm in which prospective memory cues appeared only in the final phase, prospective memory performance was better when participants were informed at encoding of the context in which cues were to appear than when participants were not informed. Additionally, task interference increased during the third phase when the cue context was previously specified. Ex-Gaussian parameter estimates revealed that task interference during the third phase was due to a greater relative frequency of longer latencies, rather than an overall increase in latencies across all trials, suggesting that participants relied primarily on transient, rather than continuous, monitoring processes to support cue detection. Functionally, variability in transient and continuous monitoring profiles was predictive of prospective memory cue detection. More generally, the results from the present study suggest that ex-Gaussian parameter estimation procedures may provide a fruitful avenue for better understanding how attention is differentially allocated to ongoing tasks, what processes might underlie monitoring behavior, and how this behavior is related to eventual intention fulfillment.

Divided attention interferes with fulfilling activity-based intentions

Two experiments were conducted to examine the effects of divided attention on activity-based prospective memory. After establishing a goal to fulfill an intention upon completion of an ongoing activity, successful completion of the intention generally suffered when attention was being devoted to an additional task (Experiment 1). Forming an implementation intention at encoding ameliorated the negative effects of divided attention (Experiment 2). The results from the present experiments demonstrate that activity-based prospective memory is susceptible to distraction and that implementing encoding strategies that enhance prospective memory performance can reduce this interference. The current work raises interesting questions about the similarities and differences between event- and activity-based prospective memories.

Navigating to new frontiers in behavioral neuroscience: traditional neuropsychological tests predict human performance on a rodent-inspired radial-arm maze.

We constructed an 11-arm, walk-through, human radial-arm maze (HRAM) as a translational instrument to compare existing methodology in the areas of rodent and human learning and memory research. The HRAM, utilized here, serves as an intermediary test between the classic rat radial-arm maze (RAM) and standard human neuropsychological and cognitive tests. We show that the HRAM is a useful instrument to examine working memory ability, explore the relationships between rodent and human memory and cognition models, and evaluate factors that contribute to human navigational ability. One-hundred-and-fifty-seven participants were tested on the HRAM, and scores were compared to performance on a standard cognitive battery focused on episodic memory, working memory capacity, and visuospatial ability. We found that errors on the HRAM increased as working memory demand became elevated, similar to the pattern typically seen in rodents, and that for this task, performance appears similar to Millers classic description of a processing-inclusive human working memory capacity of 7 ± 2 items. Regression analysis revealed that measures of working memory capacity and visuospatial ability accounted for a large proportion of variance in HRAM scores, while measures of episodic memory and general intelligence did not serve as significant predictors of HRAM performance. We present the HRAM as a novel instrument for measuring navigational behavior in humans, as is traditionally done in basic science studies evaluating rodent learning and memory, thus providing a useful tool to help connect and translate between human and rodent models of cognitive functioning.

Encountering items previously paired with prospective memory target events can serve to reactivate intentions

Two experiments were conducted to determine whether encountering items that were previously paired with prospective memory (PM) targets would serve as effective reminders and thereby improve PM performance. Experiment 1 showed that PM target detection was facilitated by encountering items (cues) that were paired with PM targets prior to intention formation, and that such facilitation was not dependent upon cues and PM targets being semantically related. Using a categorical intention, Experiment 2 showed that encountering cue items improved PM performance for all intention-related items, not just those previously paired with potential PM targets. However, the benefit of encountering cue items was moderated by the number of intervening trials between cues and targets. Overall, the data suggest that encountering items previously paired with target items induces reactivation of the intention but is only beneficial when the heightened level of activation can be maintained by working memory.

Encoding and retrieval processes involved in the access of source information in the absence of item memory.

The current study sought to examine the relative contributions of encoding and retrieval processes in accessing contextual information in the absence of item memory using an extralist cuing procedure in which the retrieval cues used to query memory for contextual information were related to the target item but never actually studied. In Experiments 1 and 2, participants studied 1 category member (e.g., onion) from a variety of different categories and at test were presented with an unstudied category label (e.g., vegetable) to probe memory for item and source information. In Experiments 3 and 4, 1 member of unidirectional (e.g., credit or card) or bidirectional (e.g., salt or pepper) associates was studied, whereas the other unstudied member served as a test probe. When recall failed, source information was accessible only when items were processed deeply during encoding (Experiments 1 and 2) and when there was strong forward associative strength between the retrieval cue and target (Experiments 3 and 4). These findings suggest that a retrieval probe diagnostic of semantically related item information reinstantiates information bound in memory during encoding that results in reactivation of associated contextual information, contingent upon sufficient learning of the item itself and the association between the item and its context information.

Individual differences in the delayed execution of prospective memories

Working memory processes play a critical role in actively maintaining, rehearsing, and retrieving goal-relevant information during cognitively engaging tasks. In the current study, we examined individual differences in prospective memory between young adults with high versus low working memory capacity (WMC) when they had to momentarily delay their intentions for either 6 or 42 s. In Experiments 1 and 2, high-WMC individuals performed significantly better at both delay intervals than did low-WMC individuals under standard ongoing task conditions. In Experiment 2, we included an interrupting task during the longer delay that decreased performance in the low-WMC relative to the high-WMC individuals. These results suggest that prospective memory performance is generally impaired across all retention intervals in low-WMC individuals, and that high-WMC individuals may be better able to retrieve the intention from long-term memory even when attention is interrupted by intervening activities.

The reactivation of associated information affects source monitoring

In this study, we examined a source-monitoring phenomenon that arises from reactivated related information from the study phase. Three experiments showed that source attributions for target events were influenced not only by the target item itself, but also by studied information about related items. In Experiment 1, source memory for target items that have a high forward association value to a single related study item (e.g., credit) were affected by the source of the associated information (e.g., card), so that memory performance was better when associated items were presented in the same source rather than a different source. A similar effect occurred with bidirectional associates (Exp. 2), as well as with synonymous pairs of words (Exp. 3). We argue that the source information of the reactivated material can be commingled with information about a candidate during a source judgment at retrieval and thereby can affect performance.

The influence of mood on the process and content of encoding future intentions.

Remembering to perform an intention in the future when some environmental cue is encountered is referred to as event-based prospective memory. The influence of mood on this future-oriented memory is unclear. By experimentally manipulating mood, the current set of experiments sought to examine the influence that differing mood states have on encoding future intentions. Participants were induced into a neutral, positive, or negative mood state at intention formation and returned to their baseline mood before beginning the prospective memory task. Relative to the neutral mood, positive mood facilitated and negative mood impaired intention encoding when neutrally toned cues were used, as evidenced by the proportion of cues subsequently detected. The use of negatively toned cues ameliorated the benefit of the positive mood but not the impairment of the negative mood. Further, reinstatement of the encoding mood during retrieval equated performance for all three mood conditions. Results suggest that encoded mood influences the future accessibility and completion of intended behaviours, perhaps through modulation of associative processing. The current study demonstrates that mood plays a determining role in encoding future intentions.