Do item-dependent context representations underlie serial order in cognition? Commentary on Logan (2021)

Logan (2021) presented an impressive unification of serial order tasks including whole report, typing, and serial recall in the form of the context retrieval and updating (CRU) model. Despite the wide breadth of the model’s coverage, its reliance on encoding and retrieving context representations that consist of the previous items may prevent it from being able to address a number of critical benchmark findings in the serial order literature that have shaped and constrained existing theories. In this commentary, we highlight three major challenges that motivated the development of a rival class of models of serial order, namely positional models. These challenges include the mixed-list phonological similarity effect, the protrusion effect, and interposition errors in temporal grouping. Simulations indicated that CRU can address the mixed list phonological similarity effect if phonological confusions can occur during its output stage, suggesting that the serial position curves from this paradigm do not rule out models that rely on inter-item associations, as has been previously been suggested. The other two challenges are more consequential for the model’s representations, and simulations indicated the model was not able to provide a complete account of them. We highlight and discuss how revisions to CRU’s representations or retrieval mechanisms can address these phenomena and emphasize that a fruitful direction forward would be to either incorporate positional representations or approximate them with its existing representations.

Intent Matters: Resolving the Intentional vs Incidental Learning Paradox in Episodic Long-term Memory

Decades of research have established that the intent to remember information has no effect on episodic long-term memory. This claim, which is routinely taught in introductory cognitive psychology courses, is based entirely on pure-list between-subject designs in which memory performance is equal for intentional and incidental learning groups. In the current ten experiments, participants made semantic judgements about each word in a list but they had to remember only words presented in a specific color. We demonstrate that in such mixed-list designs there is a substantial difference between intentionally and incidentally learned items. The first four experiments showed that this finding is independent of the remember cue onset relative to the semantic judgement. The remaining six experiments tested alternative explanations as to why intent only matters in mixed-list designs but not in pure-list between-subject designs – inhibition of incidentally learned items, output interference, selective relational encoding, and a novel selective threshold-shifting account. We found substantial support for the threshold-shifting account according to which the intent to remember boosts item-context associations in both mixed- and pure-list designs; however, in pure-list between-subject designs, participants in the incidental learning group can use a lower retrieval threshold to compensate for the weaker memory traces. This led to more extra-list intrusions in incidental learning groups; incidental learning groups also showed a source memory deficit. We conclude that intent always matters for long-term learning, but that the effect is masked in traditional between-subject designs. Our results suggest that researchers need to rethink the role of intent in long-term memory.

Do intuitive ideas of the qualities that should characterize involuntary and voluntary memories affect their classification?

It is assumed that the difference between voluntary and involuntary autobiographical memories lies in the intentionality to retrieve a memory assigned by the experimenter. Memories that are retrieved when people are instructed to do so in response to cues are considered voluntary (VAMs), those that pop up spontaneously are considered involuntary (IAMs). VAMs and IAMs so classified are also found to differ in terms of phenomenological characteristics, such as perceived accessibility, vividness etc. These differences are assumed to be due to differences in intentionality and the different retrieval processes at play. It is possible, however, that these differences (which are subjective attributions of phenomenological characteristics) are the result of metacognitive beliefs of what IAMs and VAMs should be. In two experiments, we investigated the possible role of these metacognitive beliefs. Participants rated IAMs and VAMs on a number of phenomenological characteristics in two conditions, when these memories were presented in blocks that specified whether they were retrieved in a voluntary or involuntary task, or when presented in a mixed list with no information provided. If metacognitive beliefs influence the reporting of memory properties, then the block presentation would increase the differences between the characteristics of the two types of memories. The results showed that, besides replicating the characteristics of IAMs and VAMs already observed in the literature, there were almost no differences between the blocked and the mixed lists. We discuss the results as supporting the idea that the difference in characteristics attributed to IAMs and VAMs reflect a genuine difference in the nature of the retrieval and is not the result of pre-existing metacognitive belief on what a voluntary and an involuntary memory should be.

Retrieving L2 word stress from orthography: Evidence from word naming and cross-modal priming

In this paper we investigated how L1 word stress affects L2 word naming for cognates and non-cognates in two lexical stress languages, Brazilian Portuguese (BP, L1) and American English (AE, L2). In Experiment 1, BP-AE bilinguals named a mixed list of disyllabic moderate frequency words in L1 (Portuguese) and L2 (English). In Experiment 2, Portuguese-English bilinguals named English (L2) disyllabic target words presented simultaneously with auditory Portuguese (L1) disyllabic primes. It is concluded that word stress has a task-dependent role to play in bilingual word naming and must be incorporated in bilingual models of lexical production and lexical perception and reading aloud models.

The list strength effect in source memory: Data and a global matching model

A critical constraint on models of item recognition comes from the list strength paradigm, in which a proportion of items are strengthened to observe the effect on the non-strengthened items. In item recognition, it has been widely established that increasing list strength does not impair performance, in that performance of a set of items is unaffected by the strength of the other items on the list. However, to date the effects of list strength manipulations have not been measured in the source memory task. We conducted three source memory experiments where items studied in two sources were presented in a pure weak list, where all items were presented once, and a mixed list, where half of the items in both sources were presented four times. Each experiment varied the nature of the testing format. In Experiment 1, in which each study list was only tested on one task (item recognition or source memory), a list strength effect was found in source memory while anull effect was found for item recognition. Experiments 2 and 3 showed robust null list strength effects when either the test phase (Experiment 2) or the analysis (Experiment 3) was restricted to recognized items. An extension of the Osth and Dennis (2015) model was able to account for the results in both tasks in all experiments by assuming that unrecognized items elicit guess responses in the source memory task and that there was low interference among the studied items. The results were also found to be consistent with a variant of the retrieving effectively from memory model (REM; Shiffrin & Steyvers, 1997) that uses ensemble representations.

The list strength effect in source memory: Data and a global matching model

A critical constraint on models of item recognition comes from the list strength paradigm, in which a proportion of items are strengthened to observe the effect on the non-strengthened items. In item recognition, it has been widely established that increasing list strength does not impair performance, in that performance of a set of items is unaffected by the strength of the other items on the list. However, to date the effects of list strength manipulations have not been measured in the source memory task. We conducted three source memory experiments where items studied in two sources were presented in a pure weak list, where all items were presented once, and a mixed list, where half of the items in both sources were presented four times. Each experiment varied the nature of the testing format. In Experiment 1, in which each study list was only tested on one task (item recognition or source memory), a list strength effect was found in source memory while a null effect was found for item recognition. Experiments 2 and 3 showed robust null list strength effects when either the test phase (Experiment 2) or the analysis (Experiment 3) was restricted to recognized items. An extension of the Osth and Dennis (2015) model was able to account for the results in both tasks in all experiments by assuming that unrecognized items elicit guess responses in the source memory task and that there was low interference among the studied items. The results were also found to be consistent with a variant of the retrieving effectively from memory model (REM; Shiffrin & Steyvers, 1997) that uses ensemble representations.

Local context influences memory for emotional stimuli but not electrophysiological markers of emotion-dependent attention

Emotional Enhancement of free recall can be context dependent. It is readily observed when emotional and neutral scenes are encoded and recalled together, in a ‘mixed’ list, but diminishes when these scenes are encoded separately, in ‘pure’ lists. We examined the hypothesis that this effect is due to differences of allocation of attention to neutral stimuli according to whether they are presented in mixed or pure lists, especially when encoding is intentional. Using picture stimuli that were controlled for semantic relatedness, our results contradicted this hypothesis. The amplitude of well-known electrophysiological markers of emotion-related attention - the Early Posterior Negativity (EPN), the Late Positive Potential (LPP), and the Slow Wave (SW) - was higher for emotional stimuli. Crucially, the emotional modulation of these ERPs was insensitive to list context, observed equally in pure and mixed lists. Although list context did not modulate neural markers of emotion-related attention, list context did modulate the effect of emotion on free recall. The apparent decoupling of the emotional effects on attention and memory challenges existing hypotheses accounting for the emotional enhancement of memory. We close by discussing whether findings are more compatible with an alternative hypothesis, where the magnitude of emotional memory enhancement is, at least in part, a consequence of retrieval dynamics.

Perceptual blurring and recognition memory: A desirable difficulty effect revealed

Recent research in the area of desirable difficulty—defined as processing difficulty at either encoding or retrieval that improves long-term retention—has demonstrated that perceptually blurring an item makes processing less fluent, but does not improve remembering (Yue et al., 2013). This result led us to examine more closely perceptual blurring as a potential desirable difficulty. In Experiment 1, better recognition of blurry than clear words was observed, a result that contrasts with those reported by Yue et al. This result was replicated in Experiment 2, in which both mixed-list and pure-list designs were used. The following experiments were conducted to determine when blurring does and does not result in enhanced remembering. The desirable difficulty effect observed in Experiments 1 and 2 was replicated in Experiments 3A, 3B, and 3C, despite varying encoding intent during study, context reinstatement at the time of test, study list length, and the nature of the distractor task between study and test phases. It was only in Experiments 4A and 4B that a null effect of perceptual blurring on remembering was found. These experiments demonstrated that (1) the level of blurring used is critical, with a lower blurring level producing results similar to Yue et al. (2013), and (2) the introduction of judgments of learning at the time of study eliminated the benefit of blurring on remembering. These results extend the desirable difficulty principle to encoding manipulations involving perceptual blurring, and identify judgments of learning at encoding as a powerful moderator of this particular desirable difficulty effect.

Retrieval Orientation and the Control of Recollection: An fMRI Study

This study used event-related fMRI to examine the impact of the adoption of different retrieval orientations on the neural correlates of recollection. In each of two study–test blocks, participants encoded a mixed list of words and pictures and then performed a recognition memory task with words as the test items. In one block, the requirement was to respond positively to test items corresponding to studied words and to reject both new items and items corresponding to the studied pictures. In the other block, positive responses were made to test items corresponding to pictures, and items corresponding to words were classified along with the new items. On the basis of previous ERP findings, we predicted that in the word task, recollection-related effects would be found for target information only. This prediction was fulfilled. In both tasks, targets elicited the characteristic pattern of recollection-related activity. By contrast, nontargets elicited this pattern in the picture task, but not in the word task. Importantly, the left angular gyrus was among the regions demonstrating this dissociation of nontarget recollection effects according to retrieval orientation. The findings for the angular gyrus parallel prior findings for the “left-parietal” ERP old/new effect and add to the evidence that the effect reflects recollection-related neural activity originating in left ventral parietal cortex. Thus, the results converge with the previous ERP findings to suggest that the processing of retrieval cues can be constrained to prevent the retrieval of goal-irrelevant information.