Developmental changes in the engagement of episodic retrieval processes and their relationship with working memory during the period of middle childhood

We examined the development of children's engagement of the episodic retrieval processes of recollection and familiarity and their relationship with working memory (WM). Ninety‐six children (24 in four groups aged 8, 9, 10, and 11 years) and 24 adults performed an episodic memory (EM) task involving old/new, remember/know (R/K), and source memory judgements and numerous WM tasks that assessed verbal and spatial components of WM and delayed short‐term memory (STM). Developmental changes were observed in EM with younger children (8‐, 9‐, 10‐year‐olds) making fewer remember responses than 11‐year‐olds and adults while 11‐year‐olds did not differ from adults. Only children aged 10 years plus showed a relationship between EM and WM. EM was related to verbal executive WM in 10‐ and 11‐year‐old children suggesting that children at this stage use verbal strategies to aid EM. In contrast, EM was related to spatial executive WM in adults. The engagement of episodic retrieval processes appears to be selectively related to executive components of verbal and spatial WM, the pattern of which differs in children and adults.     

Effects of environmental support on overt and covert visuospatial rehearsal

People can rehearse to-be-remembered locations either overtly, using eye movements, or covertly, using only shifts of spatial attention. The present study examined whether the effectiveness of these two strategies depends on environmental support for rehearsal. In Experiment 1, when environmental support (i.e., the array of possible locations) was present and participants could engage in overt rehearsal during retention intervals, longer intervals resulted in larger spans, whereas in Experiment 2, when support was present but participants could only engage in covert rehearsal, longer intervals resulted in smaller spans. When environmental support was absent, however, longer retention intervals resulted in smaller memory spans regardless of which rehearsal strategies were available. In Experiment 3, analyses of participants’ eye movements revealed that the presence of support increased participants’ fixations of to-be-remembered target locations more than fixations of non-targets, and that this was associated with better memory performance. Further, although the total time fixating targets increased, individual target fixations were actually briefer. Taken together, the present findings suggest that in the presence of environmental support, overt rehearsal is more effective than covert rehearsal at maintaining to-be-remembered locations in working memory, and that having more time for overt rehearsal can actually increase visuospatial memory spans.     

Dynamic relationships between phonological memory and reading: A five year longitudinal study from age 4 to 9

We reconcile competing theories of the role of phonological memory in reading development, by uncovering their dynamic relationship during the first 5 years of school. Phonological memory, reading and phoneme awareness were assessed in 780 phonics‐educated children at age 4, 5, 6 and 9. Confirmatory factor analyses demonstrated that phonological memory loaded onto two factors: verbal short‐term memory (verbal STM; phonological tasks that loaded primarily on serial order memory) and nonword repetition. Using longitudinal structural equation models, we found that verbal STM directly predicted early word‐level reading from age 4 to 6, reflecting the importance of serial‐order memory for letter‐by‐letter decoding. In contrast, reading had no reciprocal influence on the development of verbal STM. The relationship between nonword repetition and reading was bidirectional across the 5 years of study: nonword repetition and reading predicted each other both directly and indirectly (via phoneme awareness). Indirect effects from nonword repetition (and verbal STM) to reading support the view that phonological memory stimulates phonemically detailed representations through repeated encoding of complex verbal stimuli. Similarly, the indirect influence of reading on nonword repetition suggests that improved reading ability promotes the phoneme‐level specificity of phonological representations. Finally, the direct influence from reading to nonword repetition suggests that better readers use orthographic cues to help them remember and repeat new words accurately. A video abstract of this article can be viewed at https://www.youtube.com/watch?v=70LZfTR0BjE .     

Children's supernatural thinking as a signalling behaviour in early childhood

In this study, we analysed the reaction times of 137 college students when making decisions on pairs of hypothetical children verbalizing different types of vignettes and/or exhibiting different physical appearance (photographs of faces). Vignettes depicted immature and mature versions of both supernatural (e.g., ‘The sun's not out today because it's mad’ vs. ‘The sun's not out today because the clouds are blocking it’) and natural (‘I can remember all 20 cards!’ vs. ‘I can remember 6 or 7 cards’) explanations to ordinary phenomena. Photographs of children's faces were morphed with a physical appearance of approximately 4–7 years old or approximately 8–10 years old. In earlier research, immature supernatural thinking produced positive‐affect reactions from adults and older adolescents (14–18 years old) towards young children, with cognitive cues being more important than physical‐appearance cues in influencing adults’ judgements. Reaction times to make decisions varied for the Supernatural and Natural vignettes and for the immature and mature vignettes/faces, reflecting the differential cognitive effort adults used for making decisions about aspects of children's physical appearance and verbal expressions. The findings were interpreted in terms of the critical role that young children's immature supernatural thinking has on adults’ perception, analogous to the evolved role of immature physical features on adults’ perception of infants.     

How verbal memory loads consume attention

According to a traditional assumption about working memory, participants retain a series of verbal items for immediate recall using covert verbal rehearsal, without much need for attention. We reassessed this assumption by imposing a speeded, nonverbal choice reaction time (CRT) task following the presentation of each digit in a list to be recalled. When the memory load surpassed a few items, performance on the speeded CRT task became increasingly impaired. This CRT task impairment depended only on attention-related components of working memory; it was not alleviated by the presence of an auditory memory trace that automatically helped the recall of items at the ends of spoken lists. We suggest that attention-demanding refreshing of verbal stimuli occurs along with any covert rehearsal.     

不同复述条件下命名难度对图形记忆的影响

采用学习 -再认的方法对自由复述、部分特征的言语命名复述和视觉表象复述三种实验条件下图形的记忆效果进行了研究。结果表明 ,(1)图形记忆中存在明显的难度效应 ,难以命名图形的再认正确率高于易命名图形 ,反应时低于易命名图形。 (2 )被试在复述图形时 ,更倾向于选择那些难以命名的特征作为复述对象 ,以便把整个图形都记住。 (3)易命名图形的言语命名复述成绩好于视觉表象复述 ;而难以命名图形则不存在这种差异。两者自由选择时 ,将加快记忆提取的速度     

Directed remembering: subliminal cues alter nonconscious memory strategies

Much research on memory function has focused on changes in recognition performance brought about by differences in the processes engaged during encoding. In most of this work, participants either receive explicit instructions to remember particular items or they perform orienting (i.e., encoding) tasks that support different levels of memory performance. In daily life, however, the retention or dismissal of information often occurs without conscious intent, thereby suggesting an alternative, nonconscious route through which purposive remembering and forgetting can occur. Based on this line of reasoning, we speculated that recognition performance in a standard item-based forgetting paradigm may be moderated by subliminal cues that trigger the automatic activation of different mnemonic strategies. We report the results of two experiments that supported this prediction. In each experiment, the basic item-based forgetting effect was replicated, but via the subliminal presentation of "remember" and "forget" cues. In addition, cue-dependent differences in memory performance were traced to the operation of a covert rehearsal mechanism during encoding. We consider the implications of these findings for the non-conscious#10; operation of memory processes in everyday life.     

Two developmental transitions in selective remembering strategies

Two experiments were reported investigating developmental changes in the use of strategies to eliminate interference from irrelevant information in memory. The participants in the first were 7-, 9-, and 11-year-old children and those in the second were adults. In both experiments a directed forgetting paradigm was used in which the person was presented two sets of pictures but only recalled one set on a trial. On some trials there was a cue to forget the first set and to remember only the second set. There were two developmental transitions. The first was from ineffective to effective selective remembering which occurred between 7 and 11 years of age. The second, which occurred between 11 years of age and adulthood, was from the use of selective retrieval strategy to a more sophisticated rehearsal strategy. The implications of these two developmental transitions were discussed.     

Directed remembering: Subliminal cues alter nonconscious memory strategies

Much research on memory function has focused on changes in recognition performance brought about by differences in the processes engaged during encoding. In most of this work, participants either receive explicit instructions to remember particular items or they perform orienting (i.e., encoding) tasks that support different levels of memory performance. In daily life, however, the retention or dismissal of information often occurs without conscious intent, thereby suggesting an alternative, nonconscious route through which purposive remembering and forgetting can occur. Based on this line of reasoning, we speculated that recognition performance in a standard item-based forgetting paradigm may be moderated by subliminal cues that trigger the automatic activation of different mnemonic strategies. We report the results of two experiments that supported this prediction. In each experiment, the basic item-based forgetting effect was replicated, but via the subliminal presentation of “remember” and “forget” cues. In addition, cue-dependent differences in memory performance were traced to the operation of a covert rehearsal mechanism during encoding. We consider the implications of these findings for the non-conscious operation of memory processes in everyday life.     

Directed forgetting of visual symbols: Evidence for nonverbal selective rehearsal

Is selective rehearsal possible for nonverbal information? Two experiments addressed this question using the item method directed forgetting paradigm, where the advantage of remember items over forget items is ascribed to selective rehearsal favoring the remember items. In both experiments, difficult-to-name abstract symbols were presented for study, followed by a recognition test. Directed forgetting effects were evident for these symbols, regardless of whether they were or were not spontaneously named. Critically, a directed forgetting effect was observed for unnamed symbols even when the symbols were studied under verbal suppression to prevent verbal rehearsal. This pattern indicates that a form of nonverbal rehearsal can be used strategically (i.e., selectively) to enhance memory, even when verbal rehearsal is not possible.     

The eye of the retriever: developing episodic memory mechanisms in preverbal infants assessed through pupil dilation

Studying memory in infants can be challenging, as they cannot express their subjective recollection verbally. In this study we use a novel method with which we can assess episodic recognition memory through pupillometry, using identical procedures and stimuli for infants and adults. In three experiments of 4‐ and 7‐month‐old infants, and adults we show that the adult pupillary response is larger to previously seen than to never seen items (old/new effect). Pupil dilations index subjective memory experience in adults, producing distinct pupil dilations to items judged as remembered, familiar, and new, regardless of actual previous exposure (Experiment 1). Seven‐month‐old infants demonstrate a clear pupillary old/new effect, very similar to that of adults (Experiment 2), whereas 4‐month‐olds do not demonstrate such an effect (Experiment 3). Our findings suggest that the mnemonic mechanisms that serve infants' and adults' episodic recognition memory are more similar than previously asserted: they are not fully developed at 4 months of age but that there is contiguity in human episodic memory development from 7 months of age.     

Covert shifts of attention can account for the functional role of “eye movements to nothing”

When trying to remember verbal information from memory, people look at spatial locations that have been associated with visual stimuli during encoding, even when the visual stimuli are no longer present. It has been shown that such “eye movements to nothing” can influence retrieval performance for verbal information, but the mechanism underlying this functional relationship is unclear. More precisely, covert in comparison to overt shifts of attention could be sufficient to elicit the observed differences in retrieval performance. To test if covert shifts of attention explain the functional role of the looking-at-nothing phenomenon, we asked participants to remember verbal information that had been associated with a spatial location during an encoding phase. Additionally, during the retrieval phase, all participants solved an unrelated visual tracking task that appeared in either an associated (congruent) or an incongruent spatial location. Half the participants were instructed to look at the tracking task, half to shift their attention covertly (while keeping the eyes fixed). In two experiments, we found that memory retrieval depended on the location to which participants shifted their attention covertly. Thus, covert shifts of attention seem to be sufficient to cause differences in retrieval performance. The results extend the literature on the relationship between visuospatial attention, eye movements, and verbal memory retrieval and provide deep insights into the nature of the looking-at-nothing phenomenon.     

Training and transfer effects of response inhibition training in children and adults

Response inhibition is crucial for mental and physical health but studies assessing the trainability of this type of inhibition are rare. Thirty‐nine children aged 10‐12 years and 46 adults aged 18‐24 years were assigned to an adaptive go/no‐go inhibition training condition or an active control condition. Transfer of training effects to performance on tasks assessing response inhibition, interference control, working memory updating, task‐switching, and non‐verbal fluid intelligence were assessed during 3‐ and 6‐month follow‐up sessions and/or an immediate post‐training session. Significant training improvements and positive transfer effects to a similar response inhibition task with other stimuli were observed for both children and adults. Reliable albeit short‐lived transfer effects were only found for the children, specifically to working memory updating and task switching. These results suggest some potential for response‐inhibition training programs to enhance aspects of cognitive functioning in children but not adults.     

Neural activation patterns during retrieval of schema‐related memories: differences and commonalities between children and adults

Schemas represent stable properties of individuals’ experiences, and allow them to classify new events as being congruent or incongruent with existing knowledge. Research with adults indicates that the prefrontal cortex (PFC) is involved in memory retrieval of schema‐related information. However, developmental differences between children and adults in the neural correlates of schema‐related memories are not well understood. One reason for this is the inherent confound between schema‐relevant experience and maturation, as both are related to time. To overcome this limitation, we used a novel paradigm that experimentally induces, and then probes for, task‐relevant knowledge during encoding of new information. Thirty‐one children aged 8–12 years and 26 young adults participated in the experiment. While successfully retrieving schema‐congruent events, children showed less medial PFC activity than adults. In addition, medial PFC activity during successful retrieval correlated positively with children's age. While successfully retrieving schema‐incongruent events, children showed stronger hippocampus (HC) activation as well as weaker connectivity between the striatum and the dorsolateral PFC than adults. These findings were corroborated by an exploratory full‐factorial analysis investigating age differences in the retrieval of schema‐congruent versus schema‐incongruent events, comparing the two conditions directly. Consistent with the findings of the separate analyses, two clusters, one in the medial PFC, one in the HC, were identified that exhibited a memory × congruency × age group interaction. In line with the two‐component model of episodic memory development, the present findings point to an age‐related shift from a more HC‐bound processing to an increasing recruitment of prefrontal brain regions in the retrieval of schema‐related events.     

Metamemories of memory researchers

In the present study, a metamemory questionnaire was completed by three groups of individuals: memory research psychologists who attended a small international convention on everyday memory processes in the aged, academic psychologists with a limited knowledge of the memory literature, and nonpsychologist college professors. There was little evidence that memory psychologists reported using strategies to remember things that were different from the strategies of other academics. The most used and most recommended technique for remembering was to write things down, followed by general internal mnemonic systems such as organization and rehearsal. The least used and least recommended strategies for all three groups were formal mnemonic systems, such as the peg-word system or the method of loci.     

Nonspecific verbal cues alleviate forgetting by young children

Verbal reminders play a pervasive role in memory retrieval by human adults. In fact, relatively nonspecific verbal information (e.g. ‘Remember the last time we ate at that restaurant?’) will often cue vivid recollections of a past event even when presented outside the original encoding context. Although research has shown that memory retrieval by young children can be initiated by physical cues and by highly specific verbal cues, the effect of less specific verbal cues is not known. Using a Visual Recognition Memory (VRM) procedure, we examined the effect of nonspecific verbal cues on memory retrieval by 4‐year‐old children. Our findings showed that nonspecific verbal cues were as effective as highly specific nonverbal cues in facilitating memory retrieval after a 2‐week delay. We conclude that, at least by 4 years of age, children are able to use nonspecific verbal reminders to cue memory retrieval, and that the VRM paradigm may be particularly valuable in examining the age at which this initially occurs.     

An adult model of preschool children’s speech memory

In previous work, it has been demonstrated that phonetic similarity among the items in a spoken list interferes with recall much more in school-aged children than in preschool children. The basis of this developmental change, however, is unclear. In the present study we examined the possibility that a developmental increase in the use of covert verbal rehearsal accounts for the change in the effects of phonetic similarity. Adults who recalled lists of spoken words during articulatory suppression tasks that blocked covert rehearsal were found to display patterns of recall that resembled those ordinarily found in 5-year-old children. The specific aspects of rehearsal responsible for these effects also were investigated.     

Development of egocentric and allocentric spatial representations from childhood to elderly age

Spatial reference frames are fundamental to represent the position of objects or places. Although research has reported changes in spatial memory abilities during childhood and elderly age, no study has assessed reference frames processing during the entire lifespan using the same task. Here, we aimed at providing some preliminary data on the capacity to process reference frames in 283 healthy participants from 6 to 89 years of age. A spatial memory task requiring egocentric/allocentric verbal judgments about objects in peri-/extrapersonal space was used. The main goals were: (1) tracing a baseline of the normal process of development of these spatial components; (2) clarifying if reference frames are differently vulnerable to age-related effects. Results showed a symmetry between children of 6–7 years and older people of 80–89 years who were slower and less accurate than all other age groups. As regards processing time, age had a strong effect on the allocentric component, especially in extrapersonal space, with a longer time in 6- to 7-year-old children and 80- to 89-year-old adults. The egocentric component looked less affected by aging. Regarding the level of spatial ability (accuracy), the allocentric ability appeared less sensitive to age-related variations, whereas the egocentric ability progressively improved from 8 years and declined from 60 years. The symmetry in processing time and level of spatial ability is discussed in relation to the development of executive functions and to the structural and functional changes due to incomplete maturation (in youngest children) and deterioration (in oldest adults) of underlying cerebral areas.     

The effects of emotional content on reality-monitoring performance in young and older adults

Reality monitoring refers to a person's ability to distinguish between perceived and imagined events. Prior research has demonstrated that young adults show a reality-monitoring advantage for negative arousing information as compared with neutral information. The present research examined whether this reality-monitoring benefit extends to positive information in young adults and whether older adults show a reality-monitoring advantage for emotional information of either valence. Two studies revealed no evidence for a reality-monitoring advantage for positive information; in both age groups, the reality-monitoring advantage existed only for negative information. Older adults were, however, more likely to remember that a positive item had been included on a study list than they were to remember that a nonemotional item had been studied. Young adults did not show this mnemonic enhancement for positive information. These results indicate that although older adults may show some mnemonic benefits for positive information (i.e., an enhanced ability to remember that a positive item was studied), they do not always show enhanced memory for source-specifying details of a positive item's presentation.     

Navigational place learning in children and young adults as assessed with a standardized locomotor search task

Spatial behaviour was investigated using a spatial learning task based on the Radial Arm Maze, the Morris Water Maze, and open‐field search‐task procedures. Ninety‐six healthy children from six age groups (3, 4, 5, 7, 10 and 12 years) with no history of CNS disorders were studied with respect to the emergence of position‐, cue‐ and place responses. Participants were to detect x out of n hidden locations, frames of reference could be varied systematically, and three spatial memory errors and speed of navigation were recorded automatically. Task difficulties were equivalent for each age group. Results showed that navigational place learning was fully developed by the age of 10, whereas participants relied on cue orientation up to age 7. Even in the youngest group, the task could be achieved without relying on egocentric orientation, provided that proximal cues were presented. Most of the errors were of the reference memory type, whereas working memory errors were extremely rare. Speed of navigation markedly improved between age 5 and 7. An additional experiment showed that navigational place‐learning behaviour was clearly dependent on distal cues. A third study showed that in young adults, learning of the spatial layout improved, but performance on the place task did not improve any further. No sex differences were observed.