Prospective memory: the relative effects of encoding, retrieval, and the match between encoding and retrieval

Pupil size tracks cue-trace interactions during episodic memory retrieval

Our ability to remember past events requires not only storing enduring engrams or memory traces of these events, but also successfully reactivating these latent traces in response to appropriate cues at the time of retrieval-a process that has been termed ecphory. However, relatively little is known about the processes that facilitate the dynamic interactions between retrieval cues and stored memory traces that are critical for successful recognition and recollection. Recently, an intriguing link between pupil dilation and recognition memory has been identified, with studied items eliciting greater pupil dilation than unstudied items during retrieval. However, the processes contributing to this "pupillary old/new effect" remain unresolved, with current explanations suggesting that it reflects the strength of the underlying memory trace. Here, we explore the novel hypothesis that the pupillary old/new effect does not index memory strength alone, but rather reflects the facilitation of cue-trace interactions during episodic memory retrieval that may be supported by activity within the pupil-linked locus coeruleus-noradrenergic (LC-NA) arousal system. First, we show that the magnitude of pupil dilation is influenced by the degree of overlap between cue and trace information. Second, we find that the magnitude of pupil dilation reflects the amount of study contextual information reinstated during retrieval. These findings provide a novel framework for understanding the pupillary old/new effect, and identify a potential role for the LC-NA system in recognition memory retrieval.

The influence of emotional cues on prospective memory: a systematic review with meta-analyses

Remembering to perform a behaviour in the future, prospective memory, is essential to ensuring that people fulfil their intentions. Prospective memory involves committing to memory a cue to action (encoding), and later recognising and acting upon the cue in the environment (retrieval). Prospective memory performance is believed to be influenced by the emotionality of the cues, however the literature is fragmented and inconsistent. We conducted a systematic search to synthesise research on the influence of emotion on prospective memory. Sixty-seven effect sizes were extracted from 17 articles and hypothesised effects tested using three meta-analyses. Overall, prospective memory was enhanced when positively-valenced rather than neutral cues were presented (d = 0.32). In contrast, negatively-valenced cues did not enhance prospective memory overall (d = 0.07), but this effect was moderated by the timing of the emotional manipulation. Prospective memory performance was improved when negatively-valenced cues were presented during both encoding and retrieval (d = 0.40), but undermined when presented only during encoding (d = -0.25). Moderating effects were also found for cue-focality and whether studies controlled for the arousal level of the cues. The principal finding is that positively-valenced cues improve prospective memory performance and that timing of the manipulation can moderate emotional effects on prospective memory. We offer a new agenda for future empirical work and theorising in this area.

Name that Percussive Tune: Associative Memory and Amplitude Envelope

A series of experiments demonstrated novel effects of amplitude envelope on associative memory, with tones exhibiting naturally decaying amplitude envelopes (e.g., those made by two wine glasses clinking) better associated with target objects than amplitude-invariant tones. In Experiment 1 participants learned associations between household objects and 4-note tone sequences constructed of spectrally matched pure tones with either “flat” or “percussive” amplitude envelopes. Those hearing percussive tones correctly recalled significantly more sequence–object associations. Experiment 2 demonstrated that participants hearing percussive tones learned the associations more quickly. Experiment 3 used “reverse percussive” tones (percussive tones played backwards) to test whether differences in overall energy might account for this effect, finding they did not lead to the same level of performance as percussive tones. Experiment 4 varied the envelope at encoding and retrieval to determine which stage of the task was most affected by the envelope manipulation. Participants hearing percussive tones at both encoding and retrieval performed significantly better than the other three groups (i.e., flat at encoding/percussive at retrieval, etc.). We conclude that amplitude envelope plays an important role in learning and memory, a finding with relevance to psychological research on audition and associative memory, as well as practical relevance for improving human–computer interface design.

Emotional valence differentially affects encoding and retrieval of prospective memory in older adults

Studies manipulating emotional valence in prospective memory (PM) have so far revealed inconsistent results. In the present study, two experiments were conducted to systematically disentangle the effects of varying emotional valence in the encoding versus retrieval phase of PM in older adults. Results showed that, while cue valence at retrieval had no influence on PM performance, at encoding both positive and negative valence resulted in reduced PM performance. Findings suggest that emotional valence may have an influence on mnemonic processes at encoding rather than modifying cue detection in aging.

The Influences of Pre-testing Reviews and Delays on Differentialassociative Processing versus A Condition in which Students chose their Learning Strategy

Recent studies show that a new strategy called differential-associative processing is effective for learning related concepts. However our knowledge about differential-associative processing is still limited. Therefore the goals of the present study are to assess the duration of knowledge that is acquired from using differential-associative processing, to determine whether the efficacy of differential-associative processing changes with the addition of a 10-minute pre-testing review, and to compare differential-associate processing to two conditions in which students select their own learning strategy. The results revealed that differential-associative processing was a better strategy for learning related concepts than were either of the two comparison conditions. They also revealed that a 10-minute pre-testing review had a positive additive influence on differential-associative processing. Finally, although the knowledge acquired from using differential-associative processing declined with an increase in delay between learning and testing, this decline was equivalent to the decline observed in both comparison conditions.

Differential-associative processing or example elaboration: Which strategy is best for learning the definitions of related and unrelated concepts?

Definitions of related concepts (e.g., genotype-phenotype) are prevalent in introductory classes. Consequently, it is important that educators and students know which strategy(s) work best for learning them. This study showed that a new comparative elaboration strategy, called differential-associative processing, was better for learning definitions of related concepts than was an integrative elaborative strategy, called example elaboration. This outcome occurred even though example elaboration was administered in a naturalistic way (Experiment 1) and students spent more time in the example elaboration condition learning (Experiments 1, 2, 3), and generating pieces of information about the concepts (Experiments 2 and 3). Further, with unrelated concepts (morpheme-fluid intelligence), performance was similar regardless if students used differential-associative processing or example elaboration (Experiment 3). Taken as a whole, these results suggest that differential-associative processing is better than example elaboration for learning definitions of related concepts and is as good as example elaboration for learning definitions of unrelated concepts.

Testing the myth of the encoding-retrieval match

The view that successful memory performance depends importantly on the extent to which there is a match between the encoding and retrieval conditions is commonplace in memory research. However, Nairne (Memory, 10, 389-395, 2002) proposed that this idea about trace-cue compatibility being the driving force behind memory retention is a myth, because one cannot make unequivocal predictions about performance by appealing to the encoding-retrieval match. What matters instead is the relative diagnostic value of the match, and not the absolute match. Three experiments were carried out in which participants memorised word pairs and tried to recall target words when given retrieval cues. The diagnostic value of the cue was varied by manipulating the extent to which the cues subsumed other memorised words and the level of the encoding-retrieval match. The results supported Nairne's (Memory, 10, 389-395, 2002) assertion that the diagnostic value of retrieval cues is a better predictor of memory performance than the absolute encoding-retrieval match.

A large-scale comparison of prospective and retrospective memory development from childhood to middle age

We present the first large-scale comparison of prospective memory (PM) and retrospective memory (RM) from 8 to 50 years of age ( N = 318,614). Participants in an Internet study were asked to remember to click on a smiley face (single-trial event-based PM test) and to indicate whether/where a picture had changed from study to test (single-trial RM test), in both cases after retention intervals filled with working-memory tests and questionnaires. Both PM and RM improved during childhood; however, whereas maximal PM was reached by teenagers, with approximately linear decline through the 20s–40s, RM continued to improve through the 20s and 30s. On both tests, females outperformed males and achieved maximal success at earlier ages. Strikingly, 10–11-year-old girls performed significantly better than females in their late 20s on the PM test. The presence of the smiley face at encoding and temporal uncertainty (expecting it “later” rather than at the “end” of the test) both benefited PM; these effects decreased and increased, respectively, from childhood to middle age. The findings demonstrate that in a cross-sectional study (a) developmental trajectories are qualitatively different between PM and RM, and (b) the relative influence of PM cues differs between younger and older ages.