Is consolidation needed to account for retroactive interference in free recall? Interfering mental activity during the retention interval of a memory task impairs performance, in particular if the interference occurs in temporal proximity to the encoding of the to-be-remembered information. There are at least two rival theoretical accounts of this temporal gradient of retroactive interference. The cognitive neuroscience literature has suggested neural consolidation is a pivotal factor determining item recall. According to this account, interfering activity (...) interrupts consolidation processes that would otherwise stabilize the memory representations of TBR items post-encoding. Temporal distinctiveness theory, by contrast, proposes that the retrievability of items depends on their isolation in psychological time. According to this theory, information processed after the encoding of TBR material will reduce the temporal distinctiveness of the TBR information. To test between these accounts, implementations of consolidation were added to the SIMPLE model of memory and learning. We report data from two experiments utilizing a two-list free recall paradigm. Modeling results imply that SIMPLE was able to model the data and did not benefit from the addition of consolidation. It is concluded that the temporal gradient of retroactive interference cannot be taken as evidence for memory consolidation. (shrink)

ABSTRACTBecause negative emotional memories are often disruptive, we conducted two experiments to reduce these memories by using a retroactive interference paradigm. In both experiments, participants were presented with highly negative pictures followed by highly negative, moderately negative, or neutral pictures or a rest period. Then, following a filler task, participants took a surprise free recall test, recalling pictures from List 1 in Experiment 1 and from both List 1 and List 2 in Experiment 2. In both experiments, recall (...) of List 1 was reduced by List 2, indicating that RI was present. Furthermore, in Experiment 1, RI was similar between moderately negative and highly negative List 2 whereas in Experiment 2, RI was greater for highly negative List 2 than moderately negative List 2. These results showed that RI can be used to reduce negative emotional memories by making these memories inaccessible. (shrink)

Ruminative thinking, characterized by a recurrent focus on negative and self-related thought, is a key cognitive vulnerability marker of depression and, therefore, a key individual difference variable. This study aimed to develop a computational cognitive model of rumination focusing on the organization and retrieval of information in memory, and how these mechanisms differ in individuals prone to rumination and individuals less prone to rumination. Adaptive Control of Thought-Rational (ACT-R) was used to develop a rumination model by adding (...) class='Hi'>memory chunks with negative valence to the declarative memory. In addition, their strength of association was increased to simulate recurrent negative focus, thereby making it harder to disengage from. The ACT-R models were validated by comparing them against two empirical datasets containing data from control and depressed participants. Our general and ruminative models were able to recreate the benchmarks of free recall while matching the behavior exhibited by the control and the depressed participants, respectively. Our study shows that it is possible to build a computational theory of rumination that can accurately simulate the differences in free recall dynamics between control and depressed individuals. Such a model could enable a more fine-tuned investigation of underlying cognitive mechanisms of depression and potentially help to improve interventions by allowing them to more specifically target key mechanisms that instigate and maintain depression. (shrink)

Emotional processing and episodic memory are closely related throughout childhood development. With respect to emotional episodic memory, available evidence shows that the consolidation of information is accompanied by an arousal that generates longer duration and persistence of the memory representations. In the case of early stages of development (i.e., first 5 years), it is less clear how these associations emerge and are modulated by individual and environmental factors. In this study, 116 4- to 5-years old Argentinean (...) children from different socio-environmental contexts (i.e., favorable or unfavorable living conditions at home), performed a task of visual emotional memory in which they observed a set of 15 images with variable emotional valences (negative, neutral, and positive). The child’s task was to appraise each image using one of the following three possible valences: (a) drawings of faces with smiles (positive valence), (b) drawings of faces with tears and round mouth with edges down (negative valence), or (c) drawings of faces with horizontal mouth (neutral valence). Five years-old children exhibited greater accuracy appraisal. Individual differences in emotional accuracy appraisal allowed us to observe different performances in free recall of negative visual images. Accuracy appraisal did not vary between children with respect to gender, living conditions at home, or language ability. Seven to ten days after the emotional appraisal children were asked to tell the experimenter all the images they remembered (variables of interest: free recall of negative, positive, or neutral images). Results showed individual (age) differences. Specifically, 5-years-old children evoked more images than 4-years-old children. These findings contribute to the understanding of emotional memory in early developmental stages and raise the need to include emotional appraisal in the assessment of episodic memory. (shrink)

Using a paradigm that allows a quasi-continuous tracking of memory performance over time, two experiments were designed to test the hypotheses that persons with a cognitively avoidant style of coping with threat manifest a dissociation between short-term and long-term retrieval of aversive information and persons with a vigilant coping style recall aversive information particularly well after long retention intervals, provided they are free to think about aversive events. Study 1 showed that avoiders manifest a poor (...) class='Hi'>memory for aversive pictures after long retention intervals only. Study 2 replicated this finding. In addition, manipulation of the cognitive load during the retention interval influenced vigilants’ recall of aversive information in the predicted way. Results indicate that processes occurring during the retention interval are essential for individual difference in memory for aversive information and require similar attention as encoding, appraisal, and retrieval processes. (shrink)

Human beings have a memory adapted to primarily retain and recall information that favors their survival and reproduction. We tested whether the frequency and severity of environmental challenges influence adaptive memory, i.e., the ability to retain and recall adaptive information. Therefore, in a community of family farmers, we verified whether the salience index of snakes (as a proxy for the distribution of local knowledge and organization in the recall process) is determined by (1) relative abundance; (2) (...) synanthropic behavior (proxies of environmental challenge frequency); (3) aposematic intensity; (4) active defense behavior; and (5) venom lethality (proxies of environmental challenge severity). To access local knowledge, we used semi-structured interviews and free lists. Ecological information about snakes, necessary for hypothesis testing, was collected from 15 herpetologists. Our results suggest that only the frequency of an environmental challenge determines a person’s ability to retain and recall adaptive information. The severity of an environmental challenge does not determine episodic memory by itself, but only amplifies the recall of information associated with frequent challenges. Therefore, an individual’s adaptive memory is fueled by the repetition of environmental challenges. Nonetheless, when the level of biological organization shifts to the population, severity is deemed evolutionarily significant. The severity of an environmental challenge, even if it leads to the death of individuals, may contribute to the evolution of the population if there are cohesive processes within the population, such as knowledge transmission, that transform it into a new “adaptive unit.”. (shrink)

Despite the salient experience of encoding threatening events, these memories are prone to distortions and often non-veridical from encoding to recall. Further, threat has been shown to preferentially disrupt the binding of event details and enhance goal-relevant information. While extensive work has characterised distinctive features of emotional memory, research has not fully explored the influence threat has on temporal memory, a process putatively supported by the binding of event details into a temporal context. Two primary competing hypotheses (...) have been proposed; that threat can impair or enhance temporal memory. We analysed two datasets to assess temporal memory for an in-person haunted house experience. In study 1, we examined the temporal structure of memory by characterising memory contiguity in free recall as a function of individual levels of heart rate as a proxy of threat. In study 2, we replicated marginal findings of threat-related increases in memory contiguity found in study 1. We extended these findings by showing threat-related increases in recency discriminations, an explicit test of temporal memory. Together, these findings demonstrate that threat enhances temporal memory regarding free recall structure and during explicit memory judgments. (shrink)

In the present paper, we first argue that it is critical for humans to forget; that is, to have some means of preventing out-of-date information from interfering with the recall of current information. We then argue that the primary means of accomplishing such adaptive updating of human memory is retrieval inhibition: Information that is rendered out of date by new learning becomes less retrievable, but remains at essentially full strength in memory as indexed by (...) other measures, such as recognition and word-fragment completion. We conclude with a speculation that certain unconscious influences of prior events may, in fact, be stronger if those events were to be forgotten rather than to be remembered. (shrink)

Long-term memory manages its contents to facilitate adaptive behaviour, amplifying representations of information relevant to current goals and expediting forgetting of information that competes with relevant memory traces. Both mnemonic selection and inhibition maintain congruence between the contents of long-term memory and an organism’s priorities. However, the capacity of these processes to modulate affective mnemonic representations remains ambiguous. Three empirical experiments investigated the consequences of mnemonic selection and inhibition on affectively charged and neutral (...) mnemonic representations using an adapted retrieval practice paradigm. Participants encoded neutral cue words and affectively negative or neutral associates and then selectively retrieved a subset of these associates multiple times. The consequences of selection and inhibitory processes engaged during selective retrieval were evaluated on a final memory test in which recall for all studied associates was probed. Analyses of memory recall indicated that both affectively neutral and negative mnemonic representations experienced similar levels of enhancement and impairment following selective retrieval, demonstrating the susceptibility of affectively salient memories to these mnemonic processes. These findings indicate that although affective memories may be more strongly encoded in memory, they remain amenable to inhibition and flexibly adaptable to the evolving needs of the organism. (shrink)

Flax seedlings grown in the absence of environmental stimuli, stresses and injuries do not form epidermal meristems in their hypocotyls. Such meristems do form when the stimuli are combined with a transient depletion of calcium. These stimuli include the “manipulation stimulus” resulting from transferring the seedlings from germination to growth conditions. If, after a stimulus, calcium depletion is delayed, meristem production is also delayed; in other words, the meristem-production instruction can be memorised. Memorisation includes both storage and recall of (...) class='Hi'>information. Here, we focus on information recall. We show that if the first transient calcium depletion is followed by a second transient depletion there is a new round of meristem production. We also show that if an excess of calcium follows calcium depletion, meristem production is blocked; but if the excess of calcium is in turn followed by another calcium depletion, again there is a new round of meristem production. The same stored information can thus be recalled repeatedly . We describe a conceptual model that takes into account these findings. (shrink)

The inconsistent relation between word frequency and free recall performance and the non-monotonic relation found between the two cannot all be explained by current theories. We propose a theoretical framework that can explain all extant results. Based on an ecological psychology analysis of the free recall situation in terms of environmental and informational resources available to the participants, we propose that because participants’ cognitive system has been shaped by their native language, free recall performance is best understood (...) as the end result of relational properties that preexist the experimental situation and of the way the words from the experimental list interact with those. In addition to this, we borrow from predictive coding theory the idea that the brain constantly predicts “what is coming next” so that it is mainly prediction errors that will propagate information forward. Our ecological psychology analysis indicates there will be “prediction errors” because the word frequency distribution in an experimental word list is inevitably different from the particular Zipf’s law distribution of the words in the language that shaped participants’ brains. We further propose the particular distributional discrepancies inherent to a given word list will trigger, as a function of the words that are included in the list, their order, and of the words that are absent from the list, a surprisal signal in the brain, something that is isomorphic to the concept of Bayesian surprise. The precise moment when Bayesian surprise is triggered will determine to what word of the list that Bayesian surprise will be associated with, and the word the Bayesian surprise will be associated with will benefit from it and become more memorable as a direct function of the magnitude of the surprisal. Two experiments are presented that show a proxy of Bayesian surprise explains the free recall performance and that no effect of word frequency is found above and beyond the effect of that proxy variable. We then discuss how our view can account for all data extant in the literature on the effect of word frequency on free recall. (shrink)