The research presented here focused primarily on an attempt to bridge the two literatures of source memory and metameory on the topic of 'monitoring'. The contributions were two-fold: an investigation of the viability of a metacognitive judgment for SM: the judgment of source learning (JOSL), and a simultaneous investigation of the relationship of age and 'monitoring' in source memory and metacognition. In the first experiment, young participants (18-25 years of age) were asked to predict (using JOSLs) whether they would be able to discriminate between pictures that were presented to them during study, images of words they generated during study, or words they never studied in a later memory test. Participants made either immediate or delayed JOSLs (on a 0-100 scale) for each item presented during the study phase. Experiment 2 was a cross-sectional study comparing young and old adults (60-80 years of age) using a modified version of the previous task. In both experiments, intraindividual correlations of JOSLs with SM (gammas) indicated that delayed JOSLs were accurate predictors of future SM performance. There were no effects of age on gamma correlations of JOSLs with SM. Based on these results, although SM showed an age-related deficit, metacognitive predictions of SM did not show this same effect.

[Truncated abstract] The aim of the present series of studies was to identify barriers to working memory for multifeature visuospatial stimuli in normal aging. Memory for multifeature stimuli requires retention of multiple visuospatial features, as well as the relationships between features within stimuli, known as memory binding. In Experiment 1, younger people (17-25 years) and older people (66-95 years) completed a modification of Wheeler and Treisman’s (2002) visual change detection task, to determine the effects of normal aging on memory binding, and memory for multiple features ... Results indicated that older people did not have a memory binding decrement compared to younger people. Further, younger people performed more accurately when cued to attend to a specific feature, while older people’s performance did not improve with cueing ... Experiment 2 employed the binding condition and the ‘either’ condition, with stimuli presented either sequentially or simultaneously. Results were consistent with Experiment 1, with no age-related binding decrement, regardless of the method of stimulus presentation. In Experiment 1, older people demonstrated a shape memory decrement compared to younger people. Experiments 3A and 3B were performed to determine whether this result did represent a memory decrement per se, or whether it was a consequence of a shape perception decrement ... Compared to younger people, older people demonstrated a similar performance decrement across shape perception and memory tasks, indicating that their performance was mediated by an underlying perceptual decrement. Experiment 4 was conducted to determine if older people had difficulty selectively attending to a feature across multifeature stimuli, as suggested by their failure to benefit from cueing in Experiment 1 ... Older people had a greater performance decrement when the irrelevant feature was incompatible with the correct response, compared to younger people, consistent with a selective attention decrement. Experiment 5B adapted the design of Experiment 4 to both a perception task and a working memory task, while Experiment 5A identified appropriate stimulus features to use in Experiment 5B ... Overall, older people do not have particular difficulty remembering multiple visuospatial features, or binding these features within working memory. Rather, older people’s performance was marked by difficulty selectively attending to a specified feature across multifeature stimuli.

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Working memory (WM) is a process that allows for the temporary and limited storage of information for an immediate goal or to be stored into a more permanent system. A large number of studies have led to the widely accepted view that WM is mediated by the frontoparietal network (FPN), consisting of areas in the prefrontal cortex (PFC) and posterior parietal cortex (PPC). Current evidence suggests that task specific patterns of neuronal oscillatory activity within the FPN play a fundamental role in WM, and yet specific spatio-temporal properties of this activity are not well characterized. This study utilized multisite local field potential (LFP) data recorded from PFC and PPC sites in two macaque monkeys trained to perform a rule-based, Oculomotor Delayed Match-to-Sample task. The animals were required to learn which of two rules determined the correct match (Location matching or Identity matching). Following a 500 ms fixation period, a sample stimulus was presented for 500 ms, followed by a randomized delay lasting 800-1200 ms in which no stimulus was present. At the end of the delay period, a match stimulus was presented, consisting of two of three possible objects presented at two of three possible locations. When the match stimulus appeared, the monkey made a saccadic eye movement to the target. The rule in effect determined which object served as the target. Time-frequency plots of three spectral measures (power, coherence, and Wiener Granger Causality (WGC) were computed from MultiVariate AutoRegressive LFP time-series models estimated in a 100-ms window that was slid across each of three analysis epochs (fixation, sample, and delay). Low (25- 55 Hz) and high gamma (65- 100 Hz) activity were investigated separately due to evidence that they may be functionally distinct. Within each epoch, recording sites in the PPC and PFC were classified into groups according to the similarity of their power t-f plots derived by a K-means clustering algorithm. From the power-based site groups, the corresponding coherence and WGC were analyzed. This classification procedure uncovered spatial, temporal, and frequency dynamics of FPN involvement in WM and other co-occurring processes, such as sensory and target related processes. These processes were distinguishable by rule and performance accuracy across all three spectral measures- power, coherence, and WGC. Location and Identity rule were distinguishable by the low and high-gamma range. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Memory monitoring, or the ability to accurately assess one’s memory retrieval success, is known to be declined for older adults. The behavioral decline has been well explored, and is specific to tasks of source monitoring; tasks involving item memory monitoring do not show age-related deficits. This study attempts to further characterize the decline by exploring neuroanatomical contributions to the decline, and genetic influences that may explain performance variability in older adults. Older adults were genotyped for the serotonin transporter (5-HTTLPR) gene, and those that are carriers of the low-expressing allele demonstrate the expected age-related decline of source monitoring performance when compared to younger adults. Interestingly, older adults who lack this allele did not display any decline in performance when compared to younger adults. Neuroanatomical correlates of task performance indicate that prefrontal regions in the inferior and lateral cortices support accurate source memory monitoring, likely through their role in the proper selection of memory cues and inhibition of irrelevant information. This relationship suggests that age-related atrophy occurring in these structures could be responsible for the performance deficits on source memory monitoring tasks. There was no direct relationship seen between genotype for the 5-HTTLPR gene and cortical volumes, however diffusion tensor imaging shows that older adults who carry this allele have altered connections between the medial temporal lobe, responsible for memory retrieval, and prefrontal cortex, which monitors the retrieval process. Through stronger connections of critical networks, older adults who lack the 5-HTTLPR short allele may be able to compensate for the age-related atrophy seen in the prefrontal cortex. Functional results further indicate that the older adult non-carriers recruit inferior and lateral frontal regions to a greater extent than the older adult carriers during accurate memory monitoring. These results begin to suggest a neuroprotective mechanism for the 5-HTTLPR genotype, wherein some older adults may be able to postpone the expected decline of memory monitoring by retaining the ability to recruit essential inferior frontal structures through more organized white matter pathways. / text

Research into the reminiscence bump aims to improve our understanding of how the memories formed during our adolescence and early adulthood subsequently influence our autobiographical recollections later in life. The purpose of this study was to investigate the temporal dynamics of autobiographical memory in a sample involving two different age groups of adult South African participants. The main objective of the research was to explore the participants’ memories for salient events and to determine whether these memories exhibit the typical reminiscence bump that has been found in autobiographical memory research. This sample consisted of two sets of cohorts, totalling 48 research participants. The first group comprised participants ranging between the ages of 40 and 59 years, and the second group involved participants ranging between the ages of 60 to 79 years. A convergent parallel mixed method approach was adopted in this study. Both quantitative and qualitative data, on the distribution, valence and life domain importance of the reminiscence bump, were collected through the lifeline interview method. The results confirmed that reminiscence bumps are reflected in the memories of both age groups between the ages of 10 and 30 years. Most life events recalled were of positive affect thus confirming the positivity bias in older adults. The family and home life domains were indicated as the most important life domains in the autobiographical memories of both groups. The main conclusion drawn from the study was that there was not a significant difference in the dynamics of the autobiographical memories between the two groups, as reflected in the temporal characteristics of their reminiscence bumps. Future research could further explore the patterns of memories, and researchers could in particular investigate the semantic and affective aspects of these autobiographical memories in more depth. / Psychology / M.A. (Psychology)

The purposes of the present study were to investigate the relationship between short-term memory and reading in learning disabled and average learners, and to determine whether this relationship is different between ages 8 to 10 and ages 11 to 13 in these two populations. Studies have shown that children with learning disabilities tend to perform poorer on short-term memory tasks compared to children with no disabilities. The present study was conducted because the short-term memory component in the Stanford-Binet Intelligence Scale is new and it was felt that information regarding this test's usefulness with learning disabled students would be beneficial for individuals in the field of educational assessment. A total of 80 children, 39 average and 41 learning disabled were selected from the five public elementary schools that have learning disabilities classes in the Langley School District. For each group of learning disabled children selected from the learning disabilities class, an equal number of average learners was chosen from the same school. The children were divided into two age groups: 8- to 10-year-olds and 11- to 13-year-olds and then further divided into their two learning categories. Four short-term memory subtests of the Stanford-Binet Intelligence Scale: Fourth Edition: Bead Memory, Memory for Sentences, Memory for Digits and Memory for Objects and three reading comprehension subtests, from B.C. QUick Individual Educational Test, Peabody Individual Achievement Test and Test of Reading Comprehension respectively, were administered to all groups to measure short-term memory and reading. The Multivariate Analysis of Variance and the Pearson Product-Moment Correlation were used to analyse the data. Results showed that the average learners scored significantly higher than the learning disabled group in both short-term memory and reading. There was no interaction effect of learning group and age on reading or short-term memory. Significant relationships were found between short-term mmeory and reading for the average learning group but none was found for the learning disabled group. / Education, Faculty of / Graduate