Source Memory Performance Research Articles

Differential Effects of Valence and Encoding Strategy on Internal Source Memory and Judgments of Source: Exploring the Production and the Self-Reference Effect.

Item memory studies show that emotional stimuli are associated with improved memory performance compared to neutral ones. However, emotion-related effects on source memory are less consistent. The current study probed how emotional valence and specific encoding conditions influence internal source memory performance and judgments of source (JOSs). In two independent experiments, participants were required to read silently/aloud (Experiment 1) or to perform self-reference/common judgments (Experiment 2) on a list of negative/neutral/positive words. They also performed immediate JOSs ratings for each word. The study phase was followed by a test phase in which participants performed old-new judgments. In Experiment 1, the production effect was replicated for item memory, but the effects of valence on item and source memory were not significant. In Experiment 2, self-referential processing effects on item and source memory differed as a function of valence. In both experiments, JOSs ratings were sensitive to valence and encoding conditions, although they were not predictive of objective memory performance. These findings demonstrate that the effects of valence on internal source memory and JOSs are modulated by encoding strategy. Thus, the way information is encoded can shed light on how emotion might enhance, impair or exert no influence on source memory.

Effects of Pointing Gestures on Memory for (In)Congruent Stimuli in Children and Young Adults

ABSTRACTWe investigated whether finger pointing toward picture locations can be used as an external cognitive control tool to guide attention and compensate for the immature cognitive control functions in children compared with young adults. Item and source memory performance was compared for picture‐location pairs that were either semantically congruent (e.g., a cloud presented at the upper half of the screen) or incongruent (e.g., a cloud presented at the lower part of the screen). Contrary to our expectations, pointing had an adverse effect on source memory compared to visual observation only, in both age groups. As expected, superior source memory performance was found for congruent compared to incongruent picture‐locations pairs in both age groups. These findings suggest that pointing toward pictures compared to only viewing may hamper memory, and that congruent picture locations are easier to remember than incongruent ones.

Elaboration Benefits Source Memory Encoding Through Centrality Change

Variations in levels of processing affect memory encoding and subsequent retrieval performance, but it is unknown how processing depth affects communication patterns within the network of interconnected brain regions involved in episodic memory encoding. In 113 healthy adults scanned with functional MRI, we used graph theory to calculate centrality indices representing the brain regions’ relative importance in the memory network. We tested how communication patterns in 42 brain regions involved in episodic memory encoding changed as a function of processing depth, and how these changes were related to episodic memory ability. Centrality changes in right middle frontal gyrus, right inferior parietal lobule and left superior frontal gyrus were positively related to semantic elaboration during encoding. In the same regions, centrality during successful episodic memory encoding was related to performance on the episodic memory task, indicating that these centrality changes reflect processes that support memory encoding through deep elaborative processing. Similar analyses were performed for congruent trials, i.e. events that fit into existing knowledge structures, but no relationship between centrality changes and congruity were found. The results demonstrate that while elaboration and congruity have similar beneficial effects on source memory performance, the cortical signatures of these processes are probably not identical.

Predictors of Source Memory Success and Failure in Older Adults

Source memory decline has been identified as one of the types of memory most seriously affected during older age. It refers to our capacity to recollect the contextual information in which our experiences take place. Although most elderly adults will be affected by progressive source memory decline, a subset of individuals will not follow this average pattern; instead, their source memory capabilities will remain functional. Likewise, a minority of individuals will manifest an extreme decay of their source memory abilities. The objective of the present study was to identify among 120 potential predictors that significantly contributed to these two extreme source memory outcomes. Spatial source memory was measured in a sample of 519 healthy individuals between 61 and 80 years old. Individuals who performed below the 20th and above the 80th percentiles in the source memory task were defined as individuals whose episodic memory failed and succeeded, respectively. Logistic models identified five and six significant predictors of source memory success and failure in older age, respectively. High source memory performance was mainly predicted by healthy cardiovascular markers and psychological traits, whereas low source memory performance was primarily predicted by consumption habits and by less engagement in mental activities. The models identified relevant biological and life experiences that underlie these unusual source memory outcomes in older age.

Does survival context enhance memory for source? A within-subjects comparison

ABSTRACTNairne, Thompson, and Pandeirada [2007. Adaptive memory: Survival processing enhances retention. Journal of Experimental Psychology: Learning, Memory, and Cognition, 33, 263–273] demonstrated that processing words according to their relevance to a survival scenario enhanced their subsequent retrieval in recall and recognition tasks compared to a variety of control scenarios. From an adaptive perspective, it is maintained that processing words in a survival context should also enhance memory for source; however, evidence in the literature is rather mixed regarding a survival context advantage for source memory. In the current study, we conducted four experiments to systematically investigate the survival advantage in source memory, when the context itself is the source, with both recall (Experiments 1A and 1B) and recognition tests (Experiments 2A and 2B). Results showed a survival advantage for item memory over the control contexts in all experiments. The survival context advantage was not extended to source memory performance in Experiment 1A. Results from all other experiments, however, indicated a survival context advantage for both item and source memory. Findings are discussed in relation to possible proximate mechanisms underlying the survival processing effect.

Cooperative contributions of structural and functional connectivity to successful memory in aging

Understanding the precise relation between functional connectivity and structural (white matter) connectivity and how these relationships account for cognitive changes in older adults are major challenges for neuroscience. We investigate these issues using an approach in which structural equation modeling (SEM) is employed to integrate functional and structural connectivity data from younger and older adults (n = 62), analyzed with a common framework based on regions connected by canonical tract groups (CTGs). CTGs (e.g., uncinate fasciculus) serve as a common currency between functional and structural connectivity matrices, and ensure equivalent sparsity in connectome information. We used this approach to investigate the neural mechanisms supporting memory for items and memory for associations, and how they are affected by healthy aging. We found that different structural and functional CTGs made independent contributions to source and item memory performance, suggesting that both forms of connectivity underlie age-related differences in specific forms of memory. Furthermore, the relationship between functional and structural connectivity was best explained by a general relationship between latent constructs—a relationship absent in any specific CTG group. These results provide insights into the relationship between structural and functional connectivity patterns, and elucidate their relative contribution to age-related differences in source memory performance.

Influences of executive and memory functioning on memory for the sources of actions.

This research provides evidence for similarities and differences between the results of traditional source memory paradigms and results from the Person-Action Conjunction (PAC) test. In the PAC test, participants view actions performed by different actors and are later tested on their memory for which actor performed each action. The PAC test can be construed as a source memory test, with actions serving as target information and actors representing the sources of those actions. Unlike traditional source memory tests, which involve a many-to-few relation of targets to sources, the PAC test involves a many-to-many relation, typically with equal numbers of actors and actions. To test whether the relation of targets to sources influences the cognitive mechanisms underlying memory for the sources of actions, young and older participants in two experiments (N = 217) took part in the PAC test, either in the context of many actors or just two actors. Participants also received Glisky and Kong's (2008) battery of tests of executive and memory functioning. Executive functioning predicted source memory performance in older adults tested in the context of just two actors, whereas memory functioning predicted young adult performance in this context. Moreover, memory functioning predicted the performance of both age groups when tested in the context of many actors, even after controlling for memory for those actors in isolation. Both young and older adults may thus rely on basic associative mechanisms to remember the sources of actions when each actor is only encountered once in the context of performing an individual action. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Entrainment enhances theta oscillations and improves episodic memory

ABSTRACTNeural oscillations in the theta band have been linked to episodic memory, but it is unclear whether activity patterns that give rise to theta play a causal role in episodic retrieval. Here, we used rhythmic auditory and visual stimulation to entrain neural oscillations to assess whether theta activity contributes to successful memory retrieval. In two separate experiments, human subjects studied words and were subsequently tested on memory for the words (‘item recognition’) and the context in which each had been previously studied (‘source memory’). Between study and test, subjects in the entrainment groups were exposed to audiovisual stimuli designed to enhance activity at 5.5 Hz, whereas subjects in the control groups were exposed to white noise (Expt. 1) or 14 Hz entrainment (Expt. 2). Theta entrainment selectively increased source memory performance in both studies. Electroencephalography (EEG) data in Expt. 2 revealed that theta entrainment resulted in band-specific enhancement of theta power during the entrainment period and during post-entrainment memory retrieval. These results demonstrate a direct link between theta activity and episodic memory retrieval. Targeted manipulation of theta activity could be a promising new approach to enhance theta activity and memory performance in healthy individuals and in patients with memory disorders.

Impact of oscillatory tDCS targeting left prefrontal cortex on source memory retrieval

ABSTRACTResearch on transcranial direct current stimulation (tDCS) has grown rapidly, but there is controversy regarding whether and how tDCS could impact memory performance. We report a study that addressed this question by examining the effects of oscillatory tDCS (otDCS) on subsequent episodic memory performance and concomitant recordings of neural oscillations. Neural oscillations in the theta band (4–7 Hz) have been shown to be important for episodic memory and especially for source memory retrieval. Here, we tested the effects of anodal otDCS at theta (5.5 Hz) over the left DLPFC on theta oscillations and memory performance. In two sessions, participants completed an item and source recognition paradigm with word stimuli. Between study and test, participants received otDCS in one session and sham stimulation in the other. Surprisingly, behavioral results showed that, relative to the sham stimulation, otDCS impaired source memory performance. Analyses of EEG data during memory retrieval revealed that otDCS changed pre-stimulus theta power and in particular reduced the specificity of theta activity during source memory retrieval. Our results suggest that non-invasive brain stimulation can impact memory and oscillatory activity in counterintuitive ways, and that direct neural activity measures can facilitate meaningful interpretation of behavioral effects of stimulation.

The Lifespan Trajectory of the Encoding-Retrieval Flip: A Multimodal Examination of Medial Parietal Cortex Contributions to Episodic Memory.

The formation of episodic memories is associated with deactivation during encoding and activation during retrieval in the posteromedial cortex (PMC). We hypothesized that the encoding/retrieval (E/R) flip is a critical component of episodic memory across the lifespan because structural and metabolic changes in the PMC coincide with the fine tuning of the episodic memory system in development and the reductions of memory performance in aging. The aims of the present study were, first, to describe lifespan trajectories of PMC encoding and retrieval activity in 270 human participants (167 females) from 6 to 80 years of age. Our second goal was to construct a model for episodic memory development in which contributions from brain activity, cortical thickness (CT), and structural connectivity are accounted for. We found that modulation of neural activity in response to memory encoding and retrieval demands was not fully developed until adolescence and decreased from adulthood through old age. The magnitude of the E/R flip was related to source memory and 55% of the age-related variance in source memory performance during childhood and adolescence could be accounted for by the E/R flip, CT, and mean diffusivity together. However, only CT and the E/R flip provided unique contributions with which to explain memory performance. The results suggest that neural dynamics in the PMC is related to the development of episodic memory during childhood and adolescence. The similar trajectories of the E/R flip and episodic memory emergence and decline through development and aging further suggests that a lifelong relationship exists.SIGNIFICANCE STATEMENT Modulation of neural activity in the posteromedial cortex (PMC) in response to memory encoding/retrieval (E/R) demands (E/R flip) does not reach its peak until adolescence and decreases from adulthood through old age. The magnitude of the E/R flip is related to source memory and 55% of the age-related variance in source memory performance during childhood and adolescence can be accounted for by the E/R flip and brain structure together. The results suggest that neural dynamics in the PMC is related to the development of episodic memory function during childhood and adolescence and the similar trajectories of the E/R flip and episodic memory performance through development and aging suggests that a lifelong relationship exists.

When and where in aging: the role of music on source monitoring.

Difficulties in source monitoring (SM) tasks observed in healthy older adults may be linked to associative memory deficits since SM requires individuals to correctly bind and later remember these bound features to discriminate the origin of a memory. Therefore, focusing attention on discriminating factors that may attenuate older adults' difficulties in attributing contextual information to memories is necessary. We investigated the effect of affective information on source monitoring in younger and older adults by manipulating the type of affective information (pictures and music) and assessing the ability to remember spatial and temporal source details for affective pictures encoded while listening to classical music. Older and younger adults viewed a series of affective IAPS pictures presented on the left or right side of the computer screen in two different lists. At test, participants were asked to remember if the picture was seen (right/left), in which list (list1/list2) or whether it was new. Results showed that spatial information was attributed better than temporal information and emotional pictures were attributed better than neutral pictures in both younger and older adults. In addition, although music significantly increased source memory performance in both younger and older participants compared to the white noise condition, the pleasantness of music differentially affected memory for source details. The authors discuss findings in terms of an interaction between music, emotion and cognition in aging.

Adaptive Memory: Remembering Potential Mates.

According to the adaptive memory perspective, memory should function more efficiently in fitness-relevant domains. The current work explored whether there is a mnemonic tuning in a fundamental domain for human evolution: reproduction. In two experiments, female participants assessed how desirable potential male candidates (represented by a face and a short descriptor) would be in the context of a long-term mating relationship or in the context of a long-term work relationship. Then, after a short distractor task, participants performed a recognition task for the faces and a source memory task. Finally, they were asked to recall the descriptors presented during encoding. Experiment 1 used a between-subjects design, whereas Experiment 2 employed a within-subject design. In both experiments, participants remembered the faces best when they were encoded in the mating condition. Also, in Experiment 1, source memory performance was better in the mating condition than in the working condition with the reverse being true for free recall of the descriptors. The latter difference was not observed in Experiment 2. These results suggest a potential mnemonic tuning for the faces of potential mate partners.

Subjective recollection independent from multifeatural context retrieval following damage to the posterior parietal cortex

This study investigated whether damage to the posterior parietal cortex (PPC) impairs the capacity to retrieve multiple aspects of the encoding context in which items were studied, or whether it impairs the subjective awareness of recollection. Patients with lesions to the PPC (PPC patients) and healthy controls memorized words along with the position in which the words were presented on the screen and the ink color in which they were printed. We studied PPC patients' recognition and source memory performance, as well as subjective recollection as indexed by Remember/Know judgments. PPC patients had preserved recognition memory, and gave a similar number of R responses as did controls. Moreover, PPC patients' source memory performance, including memory for multiple contextual features, was similar to the controls'. However, whereas healthy controls were more likely to select R responses with correct multifeatural source judgments compared to K responses, PPC patients were not. These findings indicate that the PPC plays a role in the subjective experience and metamnemonic evaluation of memory contents.

FMRI activity during associative encoding is correlated with cardiorespiratory fitness and source memory performance in older adults

Older adults (OA), relative to young adults (YA), exhibit age-related alterations in functional Magnetic Resonance Imaging (fMRI) activity during associative encoding, which contributes to deficits in source memory. Yet, there are remarkable individual differences in brain health and memory performance among OA. Cardiorespiratory fitness (CRF) is one individual difference factor that may attenuate brain aging, and thereby contribute to enhanced source memory in OA. To examine this possibility, 26 OA and 31 YA completed a treadmill-based exercise test to evaluate CRF (peak VO2) and fMRI to examine brain activation during a face-name associative encoding task. Our results indicated that in OA, peak VO2 was positively associated with fMRI activity during associative encoding in multiple regions including bilateral prefrontal cortex, medial frontal cortex, bilateral thalamus and left hippocampus. Next, a conjunction analysis was conducted to assess whether CRF influenced age-related differences in fMRI activation. We classified OA as high or low CRF and compared their activation to YA. High fit OA (HFOA) showed fMRI activation more similar to YA than low fit OA (LFOA) (i.e., reduced age-related differences) in multiple regions including thalamus, posterior and prefrontal cortex. Conversely, in other regions, primarily in prefrontal cortex, HFOA, but not LFOA, demonstrated greater activation than YA (i.e., increased age-related differences). Further, fMRI activity in these brain regions was positively associated with source memory among OA, with a mediation model demonstrating that associative encoding activation in medial frontal cortex indirectly influenced the relationship between peak VO2 and subsequent source memory performance. These results indicate that CRF may contribute to neuroplasticity among OA, reducing age-related differences in some brain regions, consistent with the brain maintenance hypothesis, but accentuating age-differences in other regions, consistent with the brain compensation hypothesis.

Changes in the correlation between spatial and temporal source memory performance and BOLD activity across the adult lifespan

Studies investigating age-related functional differences associated with source memory have recently focused on the importance of clarifying the relationship between effects of age and performance on memory-related brain activations. One methodological challenge has been in discriminating between effects of age on memory-related brain activations that are independent from age-related differences in performance. In the current study, event-related functional magnetic resonance imaging (fMRI) was used to identify brain activity during spatial and temporal source encoding and retrieval across the adult lifespan. We used multivariate behavior partial least squares (B-PLS) to identify patterns of brain activity during source encoding and source retrieval that were associated with age and/or retrieval accuracy. The PLS analysis identified three significant effects. The first effect indicated that encoding and retrieval activity in fusiform, middle occipital–temporal and inferior parietal cortices increased with age and decreased with performance. The second effect showed that dorsolateral prefrontal cortex and limbic activity increased with age at encoding, and increased with performance at retrieval. The third effect indicated that activity in right ventrolateral prefrontal and bilateral hippocampus increased with age during retrieval and was differentially related to performance during encoding versus retrieval. We conclude that although some age-related differences in brain activity observed during source encoding and retrieval are associated with individual differences in performance, age-related differences in prefrontal and hippocampal areas exhibit more complex patterns of interactions between age, performance, and phase-related activity.

Brain–behavior relationships in source memory: Effects of age and memory ability

There is considerable evidence for age-related decrements in source memory retrieval, but the literature on the neural correlates of these impairments is mixed. In this study, we used functional magnetic resonance imaging to examine source memory retrieval-related brain activity, and the monotonic relationship between retrieval-related brain activity and source memory accuracy, as a function of both healthy aging (younger vs older) and memory ability within the older adult group (Hi-Old vs Lo-Old). Participants studied lists of word pairs, half visually, half aurally; these were re-presented visually in a scanned test phase and participants indicated if the pair was ‘seen’ or ‘heard’ in the study phase. The Lo-Old, but not the Hi-Old, showed source memory performance decrements compared to the Young. During retrieval of source memories, younger and older adults engaged lateral and medial prefrontal cortex (PFC) and medial posterior parietal (and occipital) cortices. The groups differed in how brain activity related to source memory accuracy in dorsal anterior cingulate cortex, precuneus/cuneus, and the inferior parietal cortex; in each of these areas, greater activity was associated with poorer accuracy in the Young, but with higher accuracy in the Hi-Old (anterior cingulate and precuneus/cuneus) and Lo-Old (inferior parietal lobe). Follow-up pairwise group interaction analyses revealed that greater activity in right parahippocampal gyrus was associated with better source memory in the Hi-Old, but not in the Lo-Old. We conclude that older adults recruit additional brain regions to compensate for age-related decline in source memory, but the specific regions involved differ depending on their episodic memory ability.

Task characteristics are critical for the use of familiarity: An ERP study on episodic memory development in middle childhood

Children have often been assumed to rely on familiarity in episodic memory retrieval, based on low source memory performance. However, the frontal familiarity-related event-related potential (ERP) correlate is typically absent in children, in contrast to a prominent parietal old/new effect reflecting recollection. Here, we presented identical and perceptually changed pictures after incidental and intentional encoding to assess whether (a) identical perceptual item features or (b) a high memory performance promoted by intentional encoding would elicit an ERP correlate associated with familiarity in 7-year-olds (N=20) and 10-year-olds (N=20). Despite generally high memory performance we observed frontal old/new effects in older children only, selectively for perceptually identical items after intentional encoding. By contrast, parietal old/new effects were observed in both groups. Furthermore, late parietal old/new effects were much smaller for changed items, suggesting that older children employed additional recollective search processes to differentiate between identical and changed items.

Unitization improves source memory in older adults: An event-related potential study

Aging-related decline in episodic memory, particularly in associative memory, is attributed to an impaired recollection of the specific details of a study episode. Fortunately, familiarity is relatively preserved in older adults. Previous studies have indicated that unitization is a specialized form of learning that increases the contribution of familiarity to associative retrieval. Here we examined whether older adults’ associative memory could be improved when employing an encoding strategy that encouraged unitization. Young and older adults encoded items and background colors either in a unitized condition (i.e., by imagining the color as an internal feature of the item) or in a non-unitized condition (i.e., by imagining the color as a contextual feature of the item). The participants then performed a source recognition test. The effects of unitization on the neural correlates of familiarity were measured by event-related potentials (ERPs). The age differences in source memory performance were lower in the unitized condition than in the non-unitized condition. The older adults only demonstrated neural correlates of familiarity-based source recognition in the unitized condition. These findings suggest that a unitized encoding strategy could improve source memory performance in older adults by enhancing the involvement of familiarity in source recognition.

Source memory performance is modulated by transcranial direct current stimulation over the left posterior parietal cortex

This study employed transcranial direct current stimulation (tDCS) to examine whether the left posterior parietal cortex (LPPC) is causally involved in episodic memory retrieval. Thirty-six participants were assigned to the anodal or the cathodal stimulation group with the block-randomization method and engaged in three source memory tests on three separate days. During the test phase, the participants received anodal or cathodal stimulation over the LPPC scalp region in one visit, sham over the LPPC in another visit, and anodal or cathodal stimulation over the right primary motor cortex (M1) scalp region in the other visit. The results showed that source memory accuracy, but not old/new recognition performance, decreased significantly when participants in the cathodal group received stimulation over the LPPC scalp region in comparison to the other two stimulation conditions. No such effect was found in the anodal group. These findings provide evidence for the causal relationship between the LPPC and episodic memory retrieval.

The Interaction Between Memory Trace and Memory Judgment in Age-Related Decline

Background/Study Context: Associative memory deficit and executive functioning deficit are two alternative—but nonexclusive—accounts of the episodic memory deficit observed in aging. The first explain the episodic memory decline generally observed in aging by an associative memory deficit (memory decline per se), whereas the second explains it by an executive functioning deficit. This distinction could be critical in early discrimination between healthy aging and very mild Alzheimer’s-type dementia.Methods: Memory performance was measured in older adults (n = 20) and paired younger participants (n = 20), whereas the facial expression and auditory context (spoken voice) associated with the face were manipulated between study and test. Recollection and familiarity were estimated using a remember/know judgment, and source memory performance was obtained depending on the information to retrieve.Results: Although no between-group difference was observed for correctly recognized old faces, older participants made more false alarms than younger ones, thus revealing lower discriminability (d’). Facial expression change decreased recognition for all participants, whereas auditory context change decreased recognition only for younger participants. Remember/know judgments revealed age-related deficits in both recollection and familiarity, the relative decrease in familiarity reported by older adults was particularly large in the expression change conditions, and a disadvantage in source memory performance was particularly pronounced when the task was to retrieve auditory context associated with the face at study.Conclusions: The present findings show that age-related associative memory differences occur with familiarity as well as recollection and are observed in situations that do not necessarily require conscious retrieval. This age-related decline is more prominent for multimodal (face–auditory context) than for intraitem (face-expression) associations. The value of exploring both memory trace and memory judgment was discussed, and potential applications for the development of neuropsychological tools for memory assessment in aging were highlighted.