Developmental changes in source memory

Remembering how one learned a fact can be important in itself (e.g. for considering the value of information). However, source memory is also important, along with the temporal and perceptual information on which it is based, in giving memory an episodic or autobiographical quality. The present study investigated developmental changes in children’s ability to monitor source, in a paradigm adapted from Schacter, Harbluk and McLachlan (1984). This task, unlike previous source monitoring tasks used with children, has the potential to show the existence of a serious kind of source error called source amnesia. Children of 4, 6 and 8 years participated. They also completed measures believed to assess prefrontal function. Children showed a steady improvement with age in their ability to remember facts, but showed abrupt improvement between 4 and 6 years in their ability to monitor the source of those facts. Most notably, 4–year–old children displayed a great deal of source amnesia (i.e. errors of the kind committed by populations with frontal dysfunction), but 6– and 8–year–old children showed very few such errors. In addition, source memory was related, in some analyses although not in others, to behavioral measures often used to assess prefrontal functioning. The timing of the transition in source monitoring ability is discussed, including implications for childhood amnesia.     

How generation affects source memory

Generation effects (better memory for self-produced items than for provided items) typically occur in item memory. Jurica and Shimamura (1999) reported a negative generation effect in source memory, but their procedure did not test participants on the items they had generated. In Experiment 1, participants answered questions and read statements made by a face on a computer screen. The target word was unscrambled, or letters were filled in. Generation effects were found for target recall and source recognition (which person did which task). Experiment 2 extended these findings to a condition in which the external sources were two different faces. Generation had a positive effect on source memory, supporting an overlap in the underlying mechanisms of item and source memory.     

Animal models of source memory

Source memory is the aspect of episodic memory that encodes the origin (i.e., source) of information acquired in the past. Episodic memory (i.e., our memories for unique personal past events) typically involves source memory because those memories focus on the origin of previous events. Source memory is at work when, for example, someone tells a favorite joke to a person while avoiding retelling the joke to the friend who originally shared the joke. Importantly, source memory permits differentiation of one episodic memory from another because source memory includes features that were present when the different memories were formed. This article reviews recent efforts to develop an animal model of source memory using rats. Experiments are reviewed which suggest that source memory is dissociated from other forms of memory. The review highlights strengths and weaknesses of a number of animal models of episodic memory. Animal models of source memory may be used to probe the biological bases of memory. Moreover, these models can be combined with genetic models of Alzheimer's disease to evaluate pharmacotherapies that ultimately have the potential to improve memory.     

Appearance-based inferences bias source memory

Previous research varying the trustworthiness of appearance has demonstrated that facial characteristics contribute to source memory. Two studies extended this work by investigating the contribution to source memory of babyfaceness, a facial quality known to elicit strong spontaneous trait inferences. Young adult participants viewed younger and older babyfaced and mature-faced individuals paired with sentences that were either congruent or incongruent with the target??s facial characteristics. Identifying a source as dominant or submissive was least accurate when participants chose between a target whose behavior was incongruent with facial characteristics and a lure whose face mismatched the target in appearance but matched the source memory question. In Experiment 1, this effect held true when older sources were identified, but not own-age, younger sources. When task difficulty was increased in Experiment 2, the relationship between face?Cbehavior congruence and lure facial characteristics persisted, but it was not moderated by target age even though participants continued to correctly identify fewer older than younger sources. Taken together, these results indicate that trait expectations associated with variations in facial maturity can bias source memory for both own- and other-age faces, although own-age faces are less vulnerable to this bias, as is shown in the moderation by task difficulty.     

Destination and source memory in Huntington's disease

Destination memory refers to the recall of the destination of previously relayed information, and source memory refers to the recollection of the origin of received information. We compared both memory systems in Huntington's disease (HD) participants. For this, HD participants and healthy adults had to put 12 items in a black or a white box (destination task), and to extract another 12 items from a blue or a red box (source task). Afterwards, they had to decide in which box each item had previously been deposited (destination memory), and from which box each item had previously been extracted (source memory). HD participants showed poorer source as well as destination recall performance than healthy adults in the proposed tasks. Correlation analysis showed that destination recall was significantly correlated with episodic recall in HD participants. Destination memory impairment in HD participants seems to be considerably influenced by their episodic memory performance.     

Developmental changes in memory source monitoring.

Previous research suggests that children are more likely than adults to confuse memories of actions they imagined themselves performing with memories of actions they actually performed (Realization Judgments), but are not more likely to confuse memories of actions they had imagined performing with memories of actions they saw another person perform (Reality Monitoring). We approach these findings in terms of a theory about the processes by which people identify the sources of their recollections (Source Monitoring). This approach suggests that children may be more likely than adults to confuse memories from different sources whenever the sources are highly similar to one another. Experiments 1 and 2 tested this hypothesis by manipulating the perceptual and semantic similarity of two sources of information and testing 4- and 6-year-old and adult subjects' recollection of the sources of particular pieces of information. Experiment 3 tested the hypothesis that children are more likely than adults to mistakenly identify memories of things they imagined another person doing as memories of things they witnessed that person doing. The findings indicate that (a) people are more likely to confuse memories from similar than dissimilar sources, (b) source monitoring improves during the preschool and childhood years, and (c) children may be especially vulnerable to the effects of source similarity.     

Adaptive memory: enhanced source memory for animate entities

ABSTRACT

The animacy effect refers to enhanced memory for animate over inanimate items. In two studies, we examined whether this memory advantage generalises to source memory. A multinomial processing tree model was used to disentangle item recognition, source memory, and guessing processes. In Study 1, animate and inanimate words were presented at different spatial locations on the screen. Animacy was associated with enhanced source memory for the spatial locations of the items. In Study 2, pseudowords were associated with animate and inanimate properties. Replicating previous results, the pseudowords were better remembered when they were associated with animate properties than when they were associated with inanimate properties. What is more, participants had enhanced source memory for the association between the pseudowords and the animate properties. The results strengthen the idea that animate items are associated with richer mnemonic representations than inanimate items.     

Generation difficulty and memory for source

The role of the word predictability from sentence context for reality monitoring and external source monitoring was examined in two experiments. In a reality-monitoring task, discrimination of an internal source was better in the hard than in the easy condition. It is probable that extra cognitive operations engaged during word generation in the hard condition were effective cues for reality-monitoring judgements. In contrast, in an external source-monitoring task (recognition memory of item's colour), the hard condition resulted in worse source memory for generated words than did the easy condition. This result is consistent both with an item-context trade-off hypothesis and a processing hypothesis. Greater effort involved at the time of generation might limit resources available for encoding of an external source. It is also possible that for generated words, the hard condition promoted conceptual processing instead of perceptual processing; therefore the item's colour was not effectively encoded.     

Generation difficulty and memory for source

The role of the word predictability from sentence context for reality monitoring and external source monitoring was examined in two experiments. In a reality-monitoring task, discrimination of an internal source was better in the hard than in the easy condition. It is probable that extra cognitive operations engaged during word generation in the hard condition were effective cues for reality-monitoring judgements. In contrast, in an external source-monitoring task (recognition memory of item's colour), the hard condition resulted in worse source memory for generated words than did the easy condition. This result is consistent both with an item–context trade-off hypothesis and a processing hypothesis. Greater effort involved at the time of generation might limit resources available for encoding of an external source. It is also possible that for generated words, the hard condition promoted conceptual processing instead of perceptual processing; therefore the item's colour was not effectively encoded.     

Aging, source memory, and emotion

In 2 experiments we assessed younger and older adults' ability to remember contextual information about an event. Each experiment examined memory for 3 different types of contextual information: (a) perceptual information (e.g., location of an item); (b) conceptual, nonemotional information (e.g., quality of an item); and (c) conceptual, emotional information (e.g., safety of an item). Consistent with a large literature on aging and source memory, younger adults outperformed older adults when the contextual information was perceptual in nature and when it was conceptual, but not emotional. Age differences in source memory were eliminated, however, when participants recalled emotional source information. These findings suggest that emotional information differentially engages older adults, possibly evoking enhanced elaborations and associations. The data are also consistent with a growing literature, suggesting that emotional processing remains stable with age (e.g., Carstensen & Turk-Charles, 1994, 1998; Isaacowitz, Charles, & Carstensen, 2000).     

Inconsistency effects in source memory and compensatory schema-consistent guessing

The attention–elaboration hypothesis of memory for schematically unexpected information predicts better source memory for unexpected than expected sources. In three source-monitoring experiments, the authors tested the occurrence of an inconsistency effect in source memory. Participants were presented with items that were schematically either very expected or very unexpected for their source. Multinomial processing tree models were used to separate source memory, item memory, and guessing bias. Results show an inconsistency effect in source memory accompanied by a compensatory schema-consistent guessing bias when expectancy strength is high, that is, when items are very expected or very unexpected for their source.     

Internal reinstatement hides cuing effects in source memory tasks

Reinstating source details at test often has no impact on source memory. We tested the proposition that participants internally reinstate source cues when such cues are not provided by the experimenter, thus making the external cues redundant. Participants studied words paired with either a male or a female face and were later asked to specify the gender of the face studied with each word. To disrupt the ability to internally reinstate sources, some participants saw eight male faces and eight female faces throughout the study list (multiple-face condition), making it difficult to determine which face should be internally reinstated for uncued test trials. Other participants saw only a single face for each gender (single-face condition), which should facilitate internal reinstatement. Across three experiments, participants in the multiple-face condition showed improved source discrimination when the studied faces were reinstated at test, as compared to uncued trials. In contrast, participants in the single-face condition showed no effect of the face cues. Moreover, the cuing effect for the multiple-face condition disappeared when the test structure facilitated internal reinstatement. Overall, the experiments support the contention that internal reinstatement is a natural part of source retrieval that can mask the effects of external cues.     

Aging, source memory, and misrecollections

The authors propose an illusory recollection account of why cognitive aging is associated with episodic memory deficits. After listening to statements presented by either a female or a male speaker, older adults were prone to misrecollecting past events. The authors' illusory recollection account is instantiated in a new illusory recollection signal detection model that provides a better fit of older adults' data than does the standard signal detection model. They observed that age-related differences in source memory (as measured by source d' scores) virtually disappear after accounting for the occurrence of illusory recollections. These data suggest that age-related source memory impairments are not due to older adults' remembering less diagnostic source information and having to guess more. Instead, older adults appear to misremember past events more often than younger adults.     

Enhanced processing fluency leads to biases in source memory

The present experiments were conducted to determine whether processing fluency affects source memory decisions. In the first three experiments, participants decided whether test items appeared in the same sensory modality (Experiments 1A, 1B) or perceptual form (font type, Experiment 2) at study and test. The results were consistent across the three studies and showed that perceptual priming leads to an increase in reports that stimuli were presented in the same sensory or perceptual form during the study and test phase. Experiment 3 showed that conceptual fluency affects source attributions in much the same way as perceptual fluency, and Experiment 4 showed that fluency is associated with a subjective experience of familiarity even when it might serve as a basis for source inference. These results are consistent with recent neuropsychological and neuroimaging evidence that familiarity-based processes contribute to source memory decisions under some circumstances, such as when items and contexts are unitized rather than merely bound together at encoding.     

Enhanced processing fluency leads to biases in source memory

The present experiments were conducted to determine whether processing fluency affects source memory decisions. In the first three experiments, participants decided whether test items appeared in the same sensory modality (Experiments 1A, 1B) or perceptual form (font type, Experiment 2) at study and test. The results were consistent across the three studies and showed that perceptual priming leads to an increase in reports that stimuli were presented in the same sensory or perceptual form during the study and test phase. Experiment 3 showed that conceptual fluency affects source attributions in much the same way as perceptual fluency, and Experiment 4 showed that fluency is associated with a subjective experience of familiarity even when it might serve as a basis for source inference. These results are consistent with recent neuropsychological and neuroimaging evidence that familiarity-based processes contribute to source memory decisions under some circumstances, such as when items and contexts are unitized rather than merely bound together at encoding.     

Monitoring item and source information: Evidence for a negative generation effect in source memory

Item memory and source memory were assessed in a task that simulated a social conversation. Participants generated answers to questions or read statements presented by one of three sources (faces on a computer screen). Positive generation effects were observed for item memory. That is, participants remembered topics of conversation better if they were asked questions about the topics than if they simply read statements about topics. However, a negative generation effect occurred for source memory. That is, remembering the source of some information was disrupted if participants were required to answer questions pertaining to that information. These findings support the notion that item and source memory are mediated, as least in part, by different processes during encoding.