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In several models of long-term memory it is assumed, either explicitly or implicitly, that different meanings of homonyms and even different senses of nonhomonyms have separate representations in long-term memory. While evidence has accrued, particularly from studies employing lexical decision tasks, to suggest that homonyms are multiply represented in semantic memory, claims for multiple representation of homonyms in episodic memory have tended to be made on a purely post hoc basis. The aim of the present research was to determine the manner in which homonyms are represented in episodic memory. A series of experiments were conducted in which either one or two meanings of homonyms were encoded at input. Retention of the homonyms or their biasing nouns was tested in a variety of retrieval contexts. The results obtained were consistent with a conceptualisation of episodic memory in which successive encodings of the same item are represented within the same memory trace which was established on the first occurrence of the item. When to different meanings of a homonym are encoded at input the encoded meanings will be represented within a single memory trace, with each different meaning being represented by an independent set of encoded semantic features. The generality of the framework for episodic memory which is developed is demonstrated through its interpretive application to a wide range of episodic memory phenomena.

“Despite the fact that memory in people with autism spectrum disorders (ASD) has been researched for over fifty years, there has been very little in the way of attempts to synthesize or codify the findings” (Boucher & Bowler, 2008, p. xv). It is the intent of this thesis to address this need specifically for episodic memory function in individuals with autism or Asperger’s syndrome. A scoping review was conducted on episodic memory function in this population and the findings are used to: (1) produce an episodic memory profile for individuals with autism or Asperger’s syndrome; and (2) identify gaps in the existing literature for future areas of study. The framework for the search criteria was based on Lind and Bowler’s (2008) claim of development of episodic memory being dependent on three cognitive abilities: (1) concept of self; (2) meta-representation; and (3) temporal cognition. Implications for teaching practice were discussed in light of the findings. / Thesis (Master, Education) -- Queen's University, 2012-09-24 16:42:01.194

Boston University. University Professors Program Senior theses. / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2031-01-02

The evaluation of past experience is influenced both by the strength of retrieved memories and factors in the immediate retrieval environment, including emphasised goals and cued expectations. However, the laboratory study of episodic memory has neglected such environmental influences, despite their overt contribution to real- world decision outcomes. The aim of this PhD thesis was to rectify this neglect, and clarify the interaction of memory evidence and environmental strategies in the service of strategic memory control. A related aim was to investigate whether control processes identified in the isolated domain of episodic memory in fact performed a more general or “cross-domain” function. An initial series of behavioural experiments (Experiments 1-3) elucidated an overlooked source of strategic bias in the standard recognition environment –implicit goal emphasis imparted by question format. Experiment 4 investigated whether the question bias was commonly enacted across different domains of evaluation, yielding modest evidence in favour of this underlying cross-domain function. Experiment 5 instantiated more explicit manipulation of goal emphasis and cued expectation, and recovered independent and opposing strategic effects of these two environmental factors, emerging across episodic and non-episodic domains. Experiment 6 employed a simultaneous EEG-fMRI approach to elucidate the neural correlates of memory control, identifying a modulation of the late positive event- related potential during the resolution of mnemonic conflict, which was sourced to BOLD variation in regions of the rostral cingulate zone and intraparietal sulcus. Experiment 7 used pupillometry to examine pupil-linked autonomic systems that have also been implicated in memory control, and isolated two distinct components of the dilation response evoked during environmental conflict –an “early amplitude” unexpected familiarity effect and a “trailing slope” uncertainty effect. The findings illuminate the cross-domain underpinnings of an adaptive memory control system, evidenced in behaviour and across different functional neuroimaging modalities, and across episodic and non-episodic domains of evaluation.

This thesis aims to examine the role of the hippocampus in declarative memory through the development of animal behavioural models of episodic memory for laboratory rats. Episodic memory- memory for unique events or episodes- is part of the declarative memory system thought to be mediated by the medial temporal lobe area of the brain in humans. One commonly used test of episodic memory in human subjects is paired associate learning. The first part of this thesis describes the adaptation of this human test for use with laboratory rats. Using their natural foraging tendency, rats were trained to search for different flavours of food at different locations within a large enclosure. When cued with a piece of food of a particular flavour in a separate box, rats learned to return to the place where that flavour of food had previously been found. This paradigm was used to investigate the role of the hippocampus in paired-associate learning using temporary pharmacological inactivation and permanent neurotoxic lesion techniques. The hippocampus has also been strongly implicated in spatial navigation, learning and memory in rats and humans. In the experiments described previously, attempts were therefore made to demonstrate that the results were not confounded by a simple deficit in spatial navigation. An alternative approach to studying episodic memory in the laboratory rat is to use the criteria established by Tulving in 1972 to describe episodic memory. He stated that episodic memory should encompass the memory for an event and the spatiotemporal context in which it occurred, i.e. the ”what”, ”where” and ”when” of an event. He later updated these criteria to include demonstration of autonoetic consciousness- most easily described as a sense of self awareness. Since this is difficult or impossible to demonstrate in animals, the term ”episodic-like” memory was coined (Clayton & Dickinson 1998) to describe the flexible use of information about the spatiotemporal aspects of an event by non-human species. Since it has been difficult to demonstrate the use of time (when) in rats (Bird et al; 2003, Babb & Crystal 2006a), Eacott & Norman (2004) suggested that the ”when” component could be replaced by context; i.e. another element specific to a particular event that they labelled ”which”. The next part of this thesis describes the use of the task published by Eacott & Norman to test episodic-like memory in the laboratory rat. Using the innate spontaneous behaviour of rats to explore novel aspects of their environment, they were exposed to multiple unique events. These consisted of various three-dimensional objects being presented in different locations within different contexts. Their memory for manipulations of the environment was then tested by presenting them with an event in which one combination of object, location and context was different from combinations which had previously been encountered. Due to their tendency to explore novel aspects of their environment, normal rats spent the majority of their time exploring the object that was in a novel location relative to the context in which it was presented. This successfully demonstrated integrated memory for what, where and which- similar to that previously defined by Tulving. The rats also showed that they could use this information flexibly because every trial involved unique combinations of objects, locations and contexts so there was no inadvertent semantic rule-learning involved. Permanent neurotoxic lesions of the hippocampus were used to determine the extent to which this structure is involved in memory for the what, where and which of an event. The experimental results presented in this thesis demonstrate an indisputable role for the hippocampus in a variety of tasks designed to parallel episodic memory in humans. The next steps in this line of research should involve characterisation of the roles of the various subregions of the hippocampus in episodic-like and paired associate memory.

Episodic memory, the ability to store and retrieve information from our past, is at the very heart of human experience, underpinning our identity and relationship with the world. Episodic memory is not a unitary phenomenon: in dual-process theory, researchers draw a distinction between familiarity, a rapid and automatic sense of oldness to a previously encountered stimulus ("I know that face"), and recollection, the reactivation of additional context from a particular episode ("We met at the York conference"). A fundamental objective in the study of human memory is to ground recollection and familiarity in neural terms. This requires accurately measuring the contribution of each from behavioural data, which in turn relies on an accurate characterisation of recollection. This thesis introduces a novel source retrieval task to demonstrate that recollection has two critical, and fiercely contested, properties: it is thresholded, i.e. it can fail completely, and successful recollection is graded, i.e. it varies in strength. The consequences of this characterisation are explored. Firstly, familiarity and recollection are functionally separable retrieval mechanisms. Secondly, the models currently used to measure the contribution of each are generally flawed, and a corrected model is described which better fits, and explains, the extant data. Finally, the frequency of recollection is shown to be dissociable from its strength, a result which links behavioural data more strongly than before to a neurocomputational account of episodic memory, and which suggests a relationship between the representational overlap of memory traces and their retrieval. This thesis necessitates a change in the way behavioural memory data is modelled, and consequently the interpretation of evidence underpinning neuroanatomical accounts of memory experience. Significantly, however, it also moves the field beyond a long-running debate and provides a deeper dual-process framework with which to address outstanding questions about the relationship between, and neural basis of, episodic memory processes.

From an adaptive perspective human memory ought to be strategically attuned towards information deemed to be of value according to nature's criterion; i.e. that which promotes individual survival and reproduction. The experiments in this thesis represent an interdisciplinary venture to merge cognitive psychology with social perception research in order to study how sociosexual pressures may have shaped women's episodic memory systems. A vast literature has validated sexual dimorphism as a cue by which women comparatively judge the value of potential mates in terms of their perceived biological and behavioural characteristics (e.g. heightened sexual dimorphism in men correlates with positive biological attributes but also negative behavioural traits). The first 5 experiments extend this work by focusing on the functional contribution women's episodic memory systems may play in constraining generalisations. Experiments 1 and 2 reveal a mnemonic bias in women's memory for contents of encounters with men who have (attractive) masculinised low vs. (less attractive) feminised high pitch. Experiment 3 finds a similar memory benefit for information associated either with masculinised or feminised men's faces, depending on whether women prefer masculinised or feminised characteristics in men. Data from Experiments 6 and 7 reveal further evidence of sociosexual adaptation in women's episodic memory. Memory appears to be biased towards remembering the location of women with feminised (highly attractive) facial features, i.e. high-value competitors for potential mates. While no sociosexual bias was found in women's location memory for attractive male faces, a sociosexual bias was present in women's location memory for men with attractive, low-pitch voices. Considered along with other recent adaptive memory research, the data in this thesis further erode the idea of episodic memory as a general purpose mechanism.

Empirical evidence suggesting colour influences object recognition is mixed; leading to conclusions that colour may not always be represented in object memory. Positive evidence for the representation of colour in episodic object memory is often complicated by the possibility that encoding specificity may be responsible for such observations. The current thesis examined whether colour is represented and makes an independent contribution of shape in episodic memory for familiar and novel objects, using a modified paradigm based on the typical retrieval- practice task (e.g., Anderson, Bjork, & Bjork, 1994). Participants studied pictures of objects, presented one at a time. In a subsequent practice phase, participants either performed Old/New recognition with a subset of the studied objects and their distractors (Experiments 1-7), or they rated a subset of the studied objects for attractiveness, complexity, and usefulness (Experiments 8 and 9). The critical manipulation concerned the nature of unpracticed objects. Unpracticed objects shared either shape only (Rp- Shape), colour only (Rp-Colour), both shape and colour (Rp-Both), or neither shape nor colour (Rp-Neither), with the practiced objects. Interference effects in memory between practiced and unpracticed items are revealed m the forgetting of related unpracticed items - retrieval-induced forgetting (RIF). If both shape and colour information is explicit in the object representations in episodic memory, then there would be significant RIF for unpracticed objects sharing shape only and colour only with the practiced objects. RIF was significant for Rp-Shape and Rp-Colour objects, suggesting that shape and colour are represented and independently drive competition effects in episodic object memory. The use of RIF to probe those representations improves on previous evidence, because it bypasses alternative encoding specificity explanations. The current work provides proof of concept for a modified retrieval-practice paradigm and establishes it as a tool to probe feature- based representations that do not easily lend themselves to retrieval practice.