Successful recognition memory decisions depend on mnemonic and decision making processes that are computed by multiple, distributed brain areas. However, little is known about what computations these areas perform or how these areas are connected. Here, I collected behavioral and functional magnetic resonance imaging data from humans during the performance of an old-new recognition memory task with retrospective confidence judgments. Across runs, choice bias was successfully manipulated by providing rewards for correct responses that were either symmetric (equal reward for hits and correct rejections) or asymmetric (one response worth more than the other). Successful recognition memory was associated with activation in anterior prefrontal, parahippocampal, posterior cingulate, and parietal cortex. Resting state functional connectivity demonstrated that these brain areas are organized into two distinct networks. The first network includes parahippocampal cortex and angular gyrus. The second network includes lateral prefrontal cortex and intraparietal sulcus. The hippocampal-cortical network was most active during old vs. new decisions, did not differentiate hits from false alarms, and was differentially active during low confidence old and new judgments. In contrast, while the frontoparietal network was robustly activated by hits, it was not activated during either false alarms or low confidence old judgments. Thus, these two distinct networks can be distinguished by their relative connectivity to the medial temporal lobe vs. lateral prefrontal cortex and their responses during uncertain old judgments and errors. The choice bias manipulation had opposing effects on the parietal components of these networks, which further suggests these networks make distinct contributions to mnemonic decision making. / Psychology

Episodic simulation refers to the construction of imagined, hypothetical events that might occur in one's personal future. Damage to our capacity for episodic simulation can produce grave consequences, impairing our ability to anticipate, plan, and prepare for the future. New theoretical approaches have begun to uncover the cognitive and neural mechanisms underlying episodic simulation, but much remains to be examined. The purpose of this dissertation is to further investigate the mechanisms supporting episodic simulation as well as the functions it serves. In the first study of the dissertation I examine age-related deficits in imagining the future, remembering the past, and describing the present (Paper 1). These findings replicate known deficits in older adults in episodic simulation and memory, yet provide evidence of non-episodic processes that also shape their expression. I next examine component cognitive and neural processes that are recruited to generate imagined events (Paper 2). Distinct regions of the hippocampus were active when encoding, tracking novelty, or constructing imagined events, suggesting a multifaceted role of the hippocampus in supporting episodic simulation. Finally, I present evidence that episodic simulation and memory can be used to facilitate empathy, that is, intentions to help a person in need (Paper 3). People are more willing to help a person in need after imagining or remembering helping that individual. Furthermore, the episodic vividness of these imagined or remembered events heightened intentions to help. These findings elucidate a previously unconsidered mechanism for facilitating empathy, and, in doing so, open the possibility for a new functional account of episodic simulation. I close by discussing the promise of this line of work that aims to provide new insights into the relationship between episodic simulation, memory, and empathy. / Psychology

Dual-process models propose that two processes support recognition memory; familiarity, a general sense that something has been previously encountered; and recollection, the retrieval of details concerning the context in which a previous encounter occurred. Event-related potential (ERP) studies of recognition memory have identified a set of old/new effects that are thought to reflect these processes: the 300-500ms bilateral-frontal effect, thought to reflect familiarity and the 500-800ms left-parietal effect, thought to reflect recollection. Whilst the exact functional role of these effects remains unclear, they are widely viewed as reliable indices of retrieval. The ERP literature reviewed in this thesis suggests that the characteristics of these recognition effects vary with task specific details and individual participant differences, suggesting that the recognition effects purported to index retrieval may be conditional on both task and participant. This thesis examined the influence of individual differences on behavioural measures of recognition and the neural correlates of recognition memory, focusing on factors of stimulus material, task performance and participant genotype. Clear evidence of stimulus differences were found, with pictures eliciting more anteriorly distributed effects than words, and a late onsetting frontopolar old/new effect that was unique for voices. Furthermore, the pattern of ERP activity associated with successful recognition of faces appeared to vary as a function of general face recognition ability, with participants poorer at remembering faces exhibiting a 300-500ms old/new effect not present for those good at remembering faces. The data also suggested that activity over right-frontal electrodes, evident in some previous studies, may be participant specific and could reflect additional retrieval support processes. Contrary to expectations, behavioural task performance was not found to significantly modulate the ‘typical’ recognition memory effects. However, a number of genetic polymorphisms were found to significantly influence both behavioural scores and the pattern of ERP activity associated with recognition memory. These results therefore suggest that inherent participant differences influence the neural correlates of recognition memory, in a way that variations in task performance do not. Overall, the results from this thesis therefore suggest that the ‘typical’ bilateral-frontal and left-parietal effects thought to index retrieval are not universal. Furthermore the results suggest that the specific processes engaged during retrieval (as indexed by variations in ERP activity) may be dependent on specific task requirements, stimulus material and the genetic makeup of the individual.

No description available.

The capacity to mentally project the self into the future or, what has recently been termed “episodic foresight” is an emerging topic of study in developmental psychology. The aim of this dissertation was to review available research on this topic and explore its development in two groups of children: typically-developing preschoolers and children with autism spectrum disorder (ASD). This dissertation had two main goals. The first goal was to explore whether tasks thought to measure episodic foresight in children are related and whether, as has been hypothesized, they were related to theory of mind (ToM) and executive function (EF). Study 1 showed that after controlling for age and language ability, episodic foresight tasks were not intercorrelated, nor were they individually related to ToM or EF tasks. Importantly, however, an episodic foresight composite score was related to several EF tasks. Specifically, the results suggested a significant relation between episodic foresight and inhibitory control. The second goal of this dissertation was to explore the development of episodic foresight in children with ASD. Specifically, I tested whether children with ASD would perform more poorly on a series of episodic foresight tasks than a mental-age matched group of typically-developing children. Study 2 revealed significant group differences on several episodic foresight tasks, suggesting that children with ASD showed impairments in thinking about themselves in the future. These results are a timely contribution to the research on episodic foresight and will hopefully aid in the further development of tasks that adequately measure this important cognitive ability in children.

Reliving the past requires the integration of multi-modal sensory details into a coherent mental impression of the initial event. In most people, memory for life episodes, or Autobiographical Memory (AM), is rich in sensory-perceptual elements that provide the vivid impression of travelling back in time. Abundant evidence indicates that the hippocampus plays a central role in AM recollection, but much research is still needed to determine which AM attributes engage the hippocampus at retrieval. My work assessed the relationship between hippocampal function and the perceptual richness of memory episodes. I designed a paradigm that captured the complexity of AM, and that manipulated perceptual richness while controlling for other AM confounds, such as recency, rehearsal, personal relevance, and “story” content. Participants studied and recalled perceptually enriched and impoverished laboratory events (film clips and written narratives, respectively) matched for the complexity of their storyline. An AM condition was also included for comparison. I tested healthy individuals and participants with unilateral medial temporal lobe epilepsy (mTLE), a clinical population with well documented hippocampal damage, on this paradigm. Perceptual richness was greatly reduced in people with mTLE, an effect that was most salient in the perceptually enriched conditions (AM and film clips). In a functional MRI version of this paradigm conducted on healthy individuals, I identified neural regions sensitive to the perceptual richness of AM and laboratory events, which included the anterior portion of the right hippocampus and other regions known to play a role in imagery and visual processing. In patients with right-lateralized mTLE, activation in these brain regions was markedly reduced in all memory conditions, which was consistent with the reduced perceptual richness I observed behaviourally. I reveal a clear relationship between hippocampal function and the perceptual richness of episodic memory, suggesting that the hippocampus plays a central role among brain regions that support the integration of multi-modal details into enriched memory experiences. My findings also advance our knowledge of how pathology and the nature of memory representation affect the neural correlates of episodic memory.

Reliving the past requires the integration of multi-modal sensory details into a coherent mental impression of the initial event. In most people, memory for life episodes, or Autobiographical Memory (AM), is rich in sensory-perceptual elements that provide the vivid impression of travelling back in time. Abundant evidence indicates that the hippocampus plays a central role in AM recollection, but much research is still needed to determine which AM attributes engage the hippocampus at retrieval. My work assessed the relationship between hippocampal function and the perceptual richness of memory episodes. I designed a paradigm that captured the complexity of AM, and that manipulated perceptual richness while controlling for other AM confounds, such as recency, rehearsal, personal relevance, and “story” content. Participants studied and recalled perceptually enriched and impoverished laboratory events (film clips and written narratives, respectively) matched for the complexity of their storyline. An AM condition was also included for comparison. I tested healthy individuals and participants with unilateral medial temporal lobe epilepsy (mTLE), a clinical population with well documented hippocampal damage, on this paradigm. Perceptual richness was greatly reduced in people with mTLE, an effect that was most salient in the perceptually enriched conditions (AM and film clips). In a functional MRI version of this paradigm conducted on healthy individuals, I identified neural regions sensitive to the perceptual richness of AM and laboratory events, which included the anterior portion of the right hippocampus and other regions known to play a role in imagery and visual processing. In patients with right-lateralized mTLE, activation in these brain regions was markedly reduced in all memory conditions, which was consistent with the reduced perceptual richness I observed behaviourally. I reveal a clear relationship between hippocampal function and the perceptual richness of episodic memory, suggesting that the hippocampus plays a central role among brain regions that support the integration of multi-modal details into enriched memory experiences. My findings also advance our knowledge of how pathology and the nature of memory representation affect the neural correlates of episodic memory.

Background: The relationship between average alcohol consumption and heart disease is well researched, showing a substantial cardioprotective association. This dissertation examined the epidemiological evidence for an effect of heavy episodic drinking (HED) over and above the effect of average alcohol consumption on heart disease. Methods: Electronic databases were systematically searched for epidemiological studies on the effect of HED on heart disease and identified articles were quantitatively summarized in a meta-analysis. Meta-regression models were used to examine the effect of characteristics of primary studies. Using individual-level data, semi-parametric Cox regression models were used to investigate HED exposure within narrow categories of average alcohol consumption in a US national population sample (n = 9,937) in relation to heart disease mortality in an 11-22 year follow-up. Frequency of heavy drinking episodes was used to identify latent classes of drinking history using growth mixture modeling in a sub-sample of this US cohort. Retrieved classes were used as independent variables in Cox regression models with heart disease mortality as the outcome event. Results: A pooled relative risk of 1.45 (95% confidence interval (CI): 1.24-1.70) for HED compared with non-HED drinkers with average alcohol consumption between 0.1-60 g/day was derived in a meta-analysis. A strong and consistent association with HED was found among current drinkers consuming an average of 1-2 drinks per day in the US cohort. There was no evidence of increased heart disease mortality resulting from the frequency of heavy drinking episodes before the age of forty. Conclusions: There is reasonable and consistent evidence for an association of HED and heart disease in current drinkers, negating any beneficial effect from alcohol consumption on heart health. History of frequency of heavy drinking episodes, however, showed no evidence for such an effect modification.

This thesis presents research designed to explore the role of physiological and psychological factors in mediating the effects of victimisation upon eyewitness memory. A tripartite model of arousal and memory is proposed encompassing physiological, psychological and motivational mechanisms. In order to investigate the potential role of these mechanisms, three laboratory based studies and one archival study are presented. The results of the laboratory studies suggest that physiological arousal may not influence eyewitness memory. In contrast, whilst direct support for an influence of psychological arousal is not provided, the possibility that psychological arousal may be an important factor cannot readily be dismissed. From a methodological perspective, contrary to existing laboratory-based research concerning visually-induced arousal, the results of the laboratory studies suggest that personal involvement may be an important factor influencing memory. Furthermore, the third laboratory study found that, differences in memory for emotional and neutral material may be a function of inherent differences between the material rather than an influence of arousal. Finally, in order to compare and contrast laboratory based research with the performance of real witnesses, a field based study utilising closed-circuit television to assess eyewitness accuracy for action details was conducted. In line with Studies One and Two, victims and bystanders were not found to differ in their memory performance. This study provides direct support for existing field and archival research suggesting that real victims and bystanders tend to be highly accurate in their eyewitness accounts. Taken together, the results of the research presented in this thesis suggest that whilst physiological arousal may not be an important factor influencing eyewitness memory, psychological and motivational influences may be important when witnesses are personally involved with the target incident.

The aim of this qualitative study was to explore product attachment among men and women in conjugal associations and to design a series of household objects to encourage product attachment. A preliminary study based on the interview responses of 16 married individuals was used to identify themes and to develop the instrument employed in the main study. The main study sample consisted of eight married couples and the qualitative methodology involved the thematic content analysis of their responses to a questionnaire and in-depth interviews. The findings supported product attachment theory, and masculinity and femininity was reflected by the objects that the participants perceived to be the most valuable. Men tended to prefer objects with a functional value serving a consumer experience, particularly those that they could interact with and/or express the masculine desire to be independent and take an active role. Women were more variable in their preferences, but most became attached to objects with shared, affective and/or affiliative value. The values which made an object special were found, in general, not to be common to both husband and wife; however, those objects with a shared value, reflecting episodic memories concerning their marriage, were highlighted. These findings led to the construction of a tentative explanatory model to expand product attachment theory in the context of married couples. Underpinned by this model, action is recommended to promote the design and segmented marketing of products in order to create an emotional bond for one or both conjugal partners. Designs are proposed for a series of household objects to encourage the progressive development of episodic memories among married couples. Some prospective designs of products specifically targeted to promote shared value among the married couple segment of the market, including furniture and decorative items for the home are described. Further research is recommended to expand product attachment theory to take into consideration the design of objects for the married couples market.