The role of context in producing item interactions and false memories

Cued recall with an extralist cue poses a challenge for contemporary memory theory in that there is a need to explain how episodic and semantic information are combined. A parallel activation and intersection approach proposes one such means by assuming that an experimental cue will elicit its preexisting semantic network and a context cue will elicit a list memory. These 2 sources of information are then combined by focusing on information that is common to the 2 sources. Two key predictions of that approach are examined: (a) Combining semantic and episodic information can lead to item interactions and false memories, and (b) these effects are limited to memory tasks that involve an episodic context cue. Five experiments demonstrate such item interactions and false memories in cued recall but not in free association. Links are drawn between the use of context in this setting and in other settings.     

The association of personal semantic memory to identity representations: insight into higher-order networks of autobiographical contents

Identity representations are higher-order knowledge structures that organise autobiographical memories on the basis of personality and role-based themes of one’s self-concept. In two experiments, the extent to which different types of personal semantic content are reflected in these higher-order networks of memories was investigated. Healthy, young adult participants generated identity representations that varied in remoteness of formation and verbally reflected on these themes in an open-ended narrative task. The narrative responses were scored for retrieval of episodic, experience-near personal semantic and experience-far (i.e., abstract) personal semantic contents. Results revealed that to reflect on remotely formed identity representations, experience-far personal semantic contents were retrieved more than experience-near personal semantic contents. In contrast, to reflect on recently formed identity representations, experience-near personal semantic contents were retrieved more than experience-far personal semantic contents. Although episodic memory contents were retrieved less than both personal semantic content types to reflect on remotely formed identity representations, this content type was retrieved at a similar frequency as experience-far personal semantic content to reflect on recently formed identity representations. These findings indicate that the association of personal semantic content to identity representations is robust and related to time since acquisition of these knowledge structures.     

The effect of burn injury on adolescents autobiographical memory

Autobiographical memory recall was investigated in two female adolescent groups; one group who had experienced a burn injury and a matched control group. The Burn group was not currently depressed or anxious, but scored significantly higher on the intrusion subscale of the impact of event scale compared to controls. Two autobiographical memory tasks, the autobiographical memory cueing task and the Children's Autobiographical Memory Inventory (CAMI), were used. For the cueing task, the Burn group was significantly slower to recall specific memories. This group also recalled significantly fewer specific memories and significantly more extended overgeneral memories. For the CAMI, the burns group produced significantly lower semantic and episodic recall. The Burn group also produced significant correlations between sub-scales of the impact of event scale and selected measures on the autobiographical memory tasks. Higher intrusion scores were associated with less detailed episodic recall. Higher avoidance scores were associated with longer latencies to recall memories to negative cue words and fewer specific memories to all cue words. These results are discussed from the perspective that the Burn group experienced intrusive thoughts which interfered with normal autobiographical functioning.     

Episodic and semantic contributions to older adults' autobiographical recall

The authors examined episodic and semantic contributions to 2 salient features of older adults' autobiographical recall: the reminiscence bump and the retention effect. Forty well-educated and healthy older men (mean age = 72.5 years; SD = 1.1) recalled personal memories in response to a series of cue words. They also categorized each memory as something they remembered from the past (R response) or they knew had happened in the past (K response) and indicated their ages when each memory occurred. The authors assumed that R and K responses reflected the operation of the episodic and semantic memory systems, respectively. Results showed a reminiscence bump and a retention effect for both R and K responses. The authors discuss the implications of this finding concerning the purported bases of the reminiscence bump and the retention effect as well as the notion that aging is more likely to effect episodic memory than semantic memory.     

Olfaction and emotion: The case of autobiographical memory

This study investigated (1) the influence of verbal and conceptual processing on the retrieval and phenomenological evaluation of olfactory evoked memories, and (2) whether the experienced qualities of retrieved information are affected by olfactory exposure per se. Seventy-two older adults were randomized into one of three cue conditions (odor only, name only, or odor name) and asked to relate any autobiographical event for the given cue. The results indicated that semantic knowledge of an odor's name significantly affects the age distribution of memories such that the memory peak in childhood observed for odors only was attenuated. Also, experiential factors such as pleasantness and feelings of being brought back in time were lower when odors were presented with their respective names. Olfactory evoked memories were associated with a higher emotional arousal that could not be accounted for by the perceptual stimulation alone. Taken together, the overall pattern of findings suggests that retrieval of olfactory evoked information is sensitive to semantic and conceptual processing, and that odor-evoked representations are more emotional than memories triggered by verbal information.     

Supporting older and younger adults’ memory for recent everyday events: A prospective sampling study using SenseCam

This study measured the effect of a wearable camera, SenseCam, on older and younger adults’ memories of recently experienced everyday events. Participants used SenseCam to prospectively sample events from a typical week, which they recalled two weeks later. Recall was cued by a self-generated title only (control condition), by the title and forward-order SenseCam images, or by the title and random-order SenseCam images. In the control condition, older and younger adults’ memories were comparably episodic, but older adults recalled more semantic details. Both forward- and random-order SenseCam images were associated with increased episodic and semantic recall in both groups, and there was a small but significant effect of temporal order favouring the forward-order condition. These findings suggest that SenseCam is effective in supporting retrieval of memory for recent events, and the results of the temporal order manipulation also shed light on the mechanism of SenseCam’s effect.     

Ageing and autobiographical memory for emotional and neutral events

We investigated age-related effects in recall of emotional and neutral autobiographical memories. Protocols were scored according to episodic and non-episodic detail categories using the Autobiographical Interview. Young adults recalled a greater number of episodic details compared to older adults, whereas older adults recalled more semantic details, replicating previous findings. Both young and older adults' emotional memories contained more overall detail than neutral ones, with the enhancement from emotion-specific to episodic details, but this did not alter the effect of age group on the pattern of episodic and semantic details. However, the age effect on episodic details was attenuated for neutral autobiographical memories. The findings suggest that age differences for emotional autobiographical recollection might reflect a more general pattern of age-related changes in memory, with impaired recall of episodic components and relative sparing of semantic aspects of autobiographical memory in older adults when compared to young adults.     

The impact of retrieval suppression on conceptual implicit memory

ABSTRACT

When people suppress retrieval of episodic memories, it can induce forgetting on later direct tests of memory for those events. Recent reports indicate that suppressing retrieval affects less conscious, unintentional retrieval of unwanted memories as well, at least on perceptually-oriented indirect tests. In the current study we examined how suppressing retrieval affects conceptual implicit memory for the suppressed content, using a category verification task. Participants studied cue-target words pairs in which the targets were exemplars of 22 semantic categories, such as vegetables or occupations. They then repeatedly retrieved or suppressed the targets in response to the cues for some of those pairs. Afterwards, they were exposed to the targets intermixed with novel items, one at a time, and asked to verify the membership of each of the words in a semantic category, as quickly as possible. Judgment response times to studied words were faster than to unstudied exemplars, reflecting repetition priming, as has been previously observed. Strikingly, the beneficial effects of prior exposure on response time were eliminated for targets that had been suppressed. Follow-up explicit memory tests also demonstrated that retrieval suppression continued to disrupt episodic recall for the items that had been just been re-exposed on the category verification test. These findings support the contention that the effects of retrieval suppression are not limited to episodic memory, but also affect indirect expressions of those memories on conceptually oriented tests, raising the possibility that underlying semantic representations of suppressed content are affected.     

Directed forgetting of autobiographical memory in mild Alzheimer's disease

Using the autobiographical directed forgetting method (Barnier et al., 2007), the present paper addressed the intentional inhibitory processes of episodic and semantic autobiographical memory in Alzheimer's disease (AD). Mild AD patients and healthy elderly people were instructed to either forget or to continue remembering previously generated autobiographical events. In a later recall test they were asked to reconstruct the early-generated memories regardless of the forget/remember instruction. Autobiographical reconstruction was further distributed into episodic and semantic memories. Results showed no forget instruction effect on episodic or semantic autobiographical recall with AD patients, whereas healthy elderly people were able to inhibit only episodic autobiographical memories. The findings suggest an impairment of the intentional inhibitory processes in autobiographical memory with AD and a relative preservation of these mechanisms with normal ageing. They also demonstrate an earlier decline in the intentional inhibitory processes compared to the autobiographical deterioration in AD.     

Directed forgetting of autobiographical memory in mild Alzheimer's disease

Using the autobiographical directed forgetting method (Barnier et al., 2007), the present paper addressed the intentional inhibitory processes of episodic and semantic autobiographical memory in Alzheimer's disease (AD). Mild AD patients and healthy elderly people were instructed to either forget or to continue remembering previously generated autobiographical events. In a later recall test they were asked to reconstruct the early-generated memories regardless of the forget/remember instruction. Autobiographical reconstruction was further distributed into episodic and semantic memories. Results showed no forget instruction effect on episodic or semantic autobiographical recall with AD patients, whereas healthy elderly people were able to inhibit only episodic autobiographical memories. The findings suggest an impairment of the intentional inhibitory processes in autobiographical memory with AD and a relative preservation of these mechanisms with normal ageing. They also demonstrate an earlier decline in the intentional inhibitory processes compared to the autobiographical deterioration in AD.     

Specificity of episodic and semantic aspects of autobiographical memory in relation to symptoms of posttraumatic stress disorder (PTSD)

Two studies examined the relationship between the ability to access specific autobiographical material in memory and presence/symptoms of posttraumatic stress. In Study 1, a sample of refugees with a diagnosis of posttraumatic stress disorder (PTSD) completed the Autobiographical Memory Test (AMT) in which they had to generate specific episodic autobiographical memories in response to emotion-related cue words. Results showed that reduced specificity of memories on the AMT was associated with an increased frequency of trauma-related flashbacks but with reduced use of effortful avoidance to deal with trauma-related intrusions in the day-to-day. Study 2 examined retrieval of semantic autobiographical information from previous lifetime periods in groups of cancer survivors with posttraumatic stress and healthy controls. The cancer survivors were able to generate fewer specific semantic details about the personal past compared to the controls. The more symptomatic survivors showed the greatest memory impairment. The data from both studies are discussed in terms of compromised access to specific autobiographical material in distressed trauma survivors reflecting a process of affect regulation.     

Simulating episodic memory deficits in semantic dementia with the TraceLink model

Although semantic dementia is primarily characterised by deficits in semantic memory, episodic memory is also impaired. Patients show poor recall of old autobiographical and semantic memories, with better retrieval of recent experiences; they can form new memories, and normal performance on pictorial recognition memory has been demonstrated. As these abnormalities in episodic memory are virtually a mirror image of those seen in the amnesic syndromes, semantic dementia poses a challenge to extant models of remote memory and amnesia. Here, we show that one such model, TraceLink, can reproduce some of the principal findings on episodic memory in semantic dementia. A loss of nodes and connections within the trace system, which can be identified with the temporal neocortical memory storage sites implicated in semantic dementia, simulates without further assumptions the findings reported above.     

Altering access to autobiographical episodes with prior semantic knowledge

Within autobiographical knowledge, semantic and episodic memory are traditionally considered separate, but newer models place them along a continuum, which raises the possibility of an intermediate form of knowledge - personal semantics. This study tested how different types of semantics – general semantics and two forms of personal semantics – impact access to personal episodic memories. In two experiments, participants made a series of true/false judgments about a prime statement, which reflected a general semantic fact, a context-dependent (e.g., repeated event) or context-independent (e.g., trait), personal semantic fact and then retrieved a specific past episodic memory. There was a significantly stronger priming effect for accessing specific episodic memories after judging personal semantic facts versus general facts. We also found that context-dependent and -independent personal semantic facts had separable priming effects on episodic memory. These findings support a continuum model of memory and verifies that there are multiple forms of personal knowledge.     

Simulating episodic memory deficits in semantic dementia with the TraceLink model

Although semantic dementia is primarily characterised by deficits in semantic memory, episodic memory is also impaired. Patients show poor recall of old autobiographical and semantic memories, with better retrieval of recent experiences; they can form new memories, and normal performance on pictorial recognition memory has been demonstrated. As these abnormalities in episodic memory are virtually a mirror image of those seen in the amnesic syndromes, semantic dementia poses a challenge to extant models of remote memory and amnesia. Here, we show that one such model, TraceLink, can reproduce some of the principal findings on episodic memory in semantic dementia. A loss of nodes and connections within the trace system, which can be identified with the temporal neocortical memory storage sites implicated in semantic dementia, simulates without further assumptions the findings reported above.     

More emotional facial expressions during episodic than during semantic autobiographical retrieval

There is a substantial body of research on the relationship between emotion and autobiographical memory. Using facial analysis software, our study addressed this relationship by investigating basic emotional facial expressions that may be detected during autobiographical recall. Participants were asked to retrieve 3 autobiographical memories, each of which was triggered by one of the following cue words: happy, sad, and city. The autobiographical recall was analyzed by a software for facial analysis that detects and classifies basic emotional expressions. Analyses showed that emotional cues triggered the corresponding basic facial expressions (i.e., happy facial expression for memories cued by happy). Furthermore, we dissociated episodic and semantic retrieval, observing more emotional facial expressions during episodic than during semantic retrieval, regardless of the emotional valence of cues. Our study provides insight into facial expressions that are associated with emotional autobiographical memory. It also highlights an ecological tool to reveal physiological changes that are associated with emotion and memory.     

Accurate, inaccurate and omitted details in collective emotional memories: The case of Itzhak Rabin's assassination

Collective memory of the assassination of the former Israeli Prime Minister, Itzhak Rabin, was originally examined by asking 61 Israeli students, about two weeks after the assassination (T1) and about 11 months later (T2) to fill out an open-ended questionnaire about the assassination. About 13 years later (T3) a new sample of 80 students also filled out the memory questionnaire. In T2 and T3 the participants also self-assessed various emotional and cognitive variables about their memories. All answers were segmented and categorised into accurate and inaccurate memories. Data analyses showed that the amounts of accurate memories decreased from T1 to T2 by 18 per cent, and from T2 to T3 by an additional 16 per cent, and were positively correlated in T2 with national importance and emotional reaction, and in T3 with self-assessed ability to remember events and amounts of visual representations. Content analysis of the most frequently memorised accurate, inaccurate and omitted memories showed that they displayed differential qualitative characteristics and that the most prevalent accurate narrative has varied over time. It appears that the collective memories of Rabin's assassination showed episodic features similar to those shown by eyewitnesses exposed to emotion-arousing events only once. The data suggest a distinction between episodic "collective memories" and semantic "collective knowledge".     

Intention superiority effect on implicit memory of shopping lists: Activation and inhibition processes

Intentional memory is defined as the ability to remember to perform intentions in the future. Forming an intention such as “shopping” activates access to memories related to the products on the shopping list. As Intention Superiority Effect (ISE) studies show, these memories are more accessible in semantic and episodic memory, more activated over time and protected from competing representations. The inhibition of competing representations in intentional memory has been little examined so far. In this study we attempt to analyze changes in activation in the recall of products on a shopping list and competitors through implicit memory tasks. Sixty-five participants learned two shopping lists on a computer. Later, they were told to virtually buy one of them (prospective list) and not the other (neutral list). Prior to intentional task execution, they performed an implicit retrieval task in which we manipulated the appearance or not of cues from the intentional list and analyzed the influence of the items from the intentional list on items related to intentional and neutral lists. The main result of this study is that intention retrieval by intentional cues strengthens the activation of products related to the intentional list and/or inhibits competing products related to the neutral list. The inhibition is episodic rather than semantic in nature. The ISE requires the recall of the intention during the retention period through intentional cues for maintaining the intention. This seems to defend automatic recovery theories and not the intention persistence hypothesis. Also, the results are better explained by the directed forgetting paradigm rather than by the retrieval-induced forgetting paradigm.     

Odour-induced mental time travel into the past and future: Do odour cues retain a unique link to our distant past?

Proustian memories, or memories spontaneously evoked by taste and odours, have been argued to be uniquely linked to our remote past. This view suggests an asymmetry between odour-cued memories and odour-cued representations of future events regarding their temporal distance to the present. We investigated the temporal distribution and other phenomenological qualities of autobiographical memories and future events employing a 2 (temporal direction: past vs future)×3 (cue type: verbal, visual, and odour) mixed design. We found that while odour-evoked memories were predominantly from the first decade of life, the future condition showed a marked preponderance of odour-cued events in the upcoming year. Odour-evoked memories were also less specific than the verbal and visual conditions. The odour condition was responsible for interactions concerning coherency of the events and the events’ significance to the life story. The results support the view that odours possess a unique ability to evoke remote autobiographical memories.     

Odour-induced mental time travel into the past and future: do odour cues retain a unique link to our distant past?

Proustian memories, or memories spontaneously evoked by taste and odours, have been argued to be uniquely linked to our remote past. This view suggests an asymmetry between odour-cued memories and odour-cued representations of future events regarding their temporal distance to the present. We investigated the temporal distribution and other phenomenological qualities of autobiographical memories and future events employing a 2 (temporal direction: past vs future) × 3 (cue type: verbal, visual, and odour) mixed design. We found that while odour-evoked memories were predominantly from the first decade of life, the future condition showed a marked preponderance of odour-cued events in the upcoming year. Odour-evoked memories were also less specific than the verbal and visual conditions. The odour condition was responsible for interactions concerning coherency of the events and the events' significance to the life story. The results support the view that odours possess a unique ability to evoke remote autobiographical memories.     

Semantic integration as a boundary condition on inhibitory processes in episodic retrieval

Recalling an experience often impairs the later retention of related traces, a phenomenon known as retrieval-induced forgetting (RIF). Research has shown that episodic associations protect competing memories from RIF (Anderson & McCulloch, 1999). We report 4 experiments that examined whether semantic associations also protect against RIF. In all experiments, robust RIF occurred when there were few associations between practiced and nonpracticed sets, but RIF was abolished when there were many. The benefits of semantic integration were independent of episodic integration strategies and were not mediated by intentional use of the associations. Rather, these results establish a new boundary condition on RIF--semantic integration--that has a potent impact on the magnitude of RIF and may explain variability in the RIF phenomenon.