The time required to identify a common object depends on several factors, especially pre-existing knowledge and episodic representations newly established as a result of a prior study. My research examined how these factors contribute to identification of objects (both studied and non-studied) and to performance on explicit memory tests. The overall goal was to explore the link between memory and object perception. One series of experiments examined influences due to object orientation in the plane of the page. Subjects were shown color photos of objects, and memory was assessed either with an old/new recognition test or with a test that required them to identify objects that were slowly faded in on a computer monitor. The critical variables were the type of photo — each showing either an object with a predominant or cardinal orientation (e.g., helicopter) or a non-cardinal object (e.g., pencil), and the orientation at which the photos were displayed at study and at test (e.g., rotated 0°, 120°, or 240°). For non-studied targets, identification test performance showed a large effect due to display orientation, but only for cardinal objects. For studied targets, study-to-test changes in orientation influenced priming for both non-cardinal and cardinal objects, but orientation specific priming effects (larger priming when study and test orientations matched rather than mismatched) were much larger with cardinal than non-cardinal objects, especially, when their display orientation, at test was unusual (i.e., 120°, 240°). A second series of experiments examined influences due to object size (size of an object presented alone) and relative size (size of an object relative to another object). Size manipulations had a large effect on identification of non-studied objects but study-to- test changes in size had only a minimal effect on priming. In contrast, study1to-test changes in relative size influenced recognition decision speed which is an index of priming. The combined findings suggest that both semantic and episodic representations behave as if they coded orientation but only for cardinal objects. They also suggest that episodic representations code relative size but not size information. The findings are explained by the instance views of memory. / Arts, Faculty of / Psychology, Department of / Graduate

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Individual differences on complex memory spans predict a variety of higher-order cognitive tasks (e.g. reading comprehension, reasoning, following direction) as well as low-level attention tasks (e.g. Stroop, dichotic listening, antisaccade). The current study attempted to better determine the role of individual differences in complex memory span and episodic retrieval. Specifically, two experiments explored the possibility that individual differences in complex memory span reflect differences in the ability to successfully retrieve items from secondary memory via a cue-dependent search process. High and low complex span participants were tested in delayed (Experiment 1) and continuous distractor (Experiment 2) free recall with varying list-lengths. Across both experiments low spans recalled fewer items than high spans, recalled more previous list intrusions than high spans, and recalled at a slower rate than high spans. It is argued that low spans search through a larger set of items than high spans and, thus low spans episodic retrieval deficits are associated with an inability to use cues to guide a search and retrieval process of secondary memory. Implications for dual-component models of memory are discussed.

[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.

Gestures have been shown to enhance memory recall for children and adults, but little research has investigated the benefits of gesturing to recall in older adult populations. While theory suggests that older adults may be less embodied, that their cognitive and perceptual processes may be less grounded in their sensorimotor capacities, the literature is unclear on whether or not gesturing is still associated with memory in this population. To test the effect of gesturing on recall we compare 58 younger (20-29 yrs) and 62 older (60-85yrs) adults’ performance on an episodic memory recall task (immediately, and at a 3-week delay) after randomly assigning participants to two conditions (instructed gesture or free gesture). In the free gesture condition participants were allowed to freely gesture while describing 26 3-second-long vignettes. Participants in the instructed gesture condition were additionally asked to provide meaningful gestures while providing descriptions to vignettes. Analyzing observational data from the free gesture conditions, we found that both immediately and at a delay, younger and older adults recalled more of the vignettes that they had spontaneously gestured for than those that they had not gestured for. When looking at the effects of instructing gesture, we found that asking older adults to gesture increased their overall recall of vignettes at a delay when compared to older adults left to freely gesture. The same increase to recall was not found for younger adults. These findings suggest that spontaneous gesturing at encoding is just as significant to episodic memory recall for older adults as it is for younger adults, and that asking older adults to gesture may additionally benefit episodic memory for older adults.

by Tracy Man-kiu Ma. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 48-61). / Abstract and appendix in English and Chinese. / ABSTRACT --- p.ii / ACKNOWLEDGEMENTS --- p.iii / TABLE OF CONTENTS --- p.iv / LIST OF TABLES --- p.vi / LIST OF FIGURES --- p.vii / LIST OF APPENDICES --- p.viii / Chapter CHAPTER ONE- --- INTRODUCTION / Mesial temporal lobe and its sequel of damages --- p.1 / Mesial temporal lobe pathologies --- p.2 / Memory assessment instruments and the Hong Kong List Learning Test --- p.4 / The receiver operating characteristics (ROC) analysis --- p.6 / Purpose of the present study --- p.7 / Chapter CHAPTER TWO- --- METHOD / Participants --- p.9 / Materials --- p.10 / Procedure --- p.13 / Statistical analysis --- p.15 / Chapter CHAPTER THREE - --- RESULTS / Memory Profiles of NPC Patients with bilateral temporal lobe lesions --- p.18 / Receiver operating characteristics (ROC) analysis for test performance --- p.26 / Validity and reliability --- p.33 / Chapter CHAPTER FOUR - --- DISCUSSION / The clinical utility of the blocked condition --- p.39 / Optimal cutoff scores for sensitivity and specificity --- p.40 / Memory profiles of NPC patients and its implications --- p.42 / Limitations --- p.45 / Conclusions --- p.46 / REFERENCES --- p.48 / APPENDICES --- p.62