There has long been interest in the effect of repetition on memory amongst cognitive psychologists. A major area of research has examined how repetition at study improves encoding and subsequent memory performance. Another focus in the literature has been on manipulating fluency at retrieval to influence feelings of familiarity, with item repetition at test inducing a classic false recognition effect. Examination of these disparate areas of research hints that similar mechanisms may be operational in producing effects of repetition at study and repetition at test. Work from the false recognition literature suggests that items are more likely to be classified as “old” if they are made to be fluent at test. In other words, fluency may be used as a cue to indicate that information is already known. This fluency attribution process may also influence encoding: if increased fluency signals that information is known, then there may be no need to encode that information. The empirical goal of this thesis was first to better understand the impact of repetition on encoding, and then to better understand the role of fluency when both learning and retrieving information. This thesis documents some of the first examples of a counter-intuitive repetition decrement effect, in which items seen a single time are better remembered than items seen twice in succession. Evidence connecting this repetition decrement effect to effects of false recognition is presented, with the suggestion of a common process leading to these two memory effects. More important, this thesis demonstrates the impact of fluency at both encoding and retrieval, and can allow for better understanding of how human cognition operates on a daily basis. / Dissertation / Doctor of Philosophy (PhD)

This thesis explores the role of gist memory and gist representation in the formation of false recognition, specifically in the Deese, Roediger and McDermott Paradigm. We found that normal individuals displayed a range of susceptibility to false recognition and true recognition and this was related to their scores on both the Autism Spectrum Quotient and the Toronto-Alexithymia Scale. More ‘male-brained’ participants exhibited less susceptibility to false recognition but also less veridical recognition. The reverse was true for more ‘female-brained’ participants. The idea of false recognition and gist memory lying along a continuum was further emphasised by work on individuals with Autism Spectrum Disorder. We found they were less susceptible to false recognition but also produced less veridical recognition. We also found differences in performance between two groups of autism individuals who also differed in age. The results of further manipulations using both picture and word paradigms suggested that gist memory could be improved in younger individuals with autism. We also examined a patient group with Functional Memory Disorder using the DRM paradigm and a confabulation task and found them less able to produce true recognition in the DRM compared with a control group. Their memory impairments could not be attributed to depression since none were clinically depressed, so we suggested that they represent the tale end of impairment to gist memory. We also explored gist memory in a patient with dense anterograde amnesia who showed reduced true recognition and a tendency to reduced false recognition, but through manipulation of the stimuli using word and pictorial material she could perform like controls due to improved item-specific discrimination. A new face recognition paradigm was also tested in which she showed a tendency towards increased false recognition in comparison with controls. Finally, we suggest the use of the DRM paradigm as a test for memory malingering since we found participants could not replicate the performance of amnesia patients without a cost in their response latencies. This is discussed through the case study of GC a man suspected of exaggerating his memory symptoms.

Face recognition involves a number of complex cognitive processes, including memory, executive functioning, and perception. A breakdown of one or more of these processes may result in false facial recognition, a memory distortion in which one mistakenly believes that novel faces are familiar. This study examined the cognitive mechanisms underlying false facial recognition in healthy older and younger adults, patients with frontotemporal dementia, and individuals with congenital prosopagnosia. Participants completed face recognition memory tests that included several different types of lures, as well as tests of face perception. Older adults demonstrated a familiarity-based response strategy, reflecting a deficit in source monitoring and impaired recollection of context, as they could not reliably discriminate between study faces and highly familiar lures. In patients with frontotemporal dementia, temporal lobe atrophy alone was associated with a reduction of true facial recognition, while concurrent frontal lobe damage was associated with increased false recognition, a liberal response bias, and an overreliance on "gist" memory when making recognition decisions. Individuals with congenital prosopagnosia demonstrated deficits in configural processing of faces and a reliance on feature-based processing, leading to false recognition of lures that had features in common from study to test. These findings may have important implications for the development of training programs that could serve to help individuals improve their ability to accurately recognize faces.

Many items encoded into episodic memory are highly similar – seeing a stranger’s car may result in a memory representation which overlaps in many features with the memory of your friend’s car. To avoid falsely recognising the novel but similar car, it is important for the representations to be distinguished in memory. Even in healthy young adults failures of this mnemonic discrimination lead relatively often to false recognition, and such errors become substantially more frequent in older age. Whether an item’s representation is discriminated from similar memory representations depends critically on how it is encoded. However, the precise encoding mechanisms involved remain poorly understood. Establishing the determinants of successful mnemonic discrimination is essential for future research into strategies or interventions to prevent recognition errors, particularly in the context of age-related decline. A fuller understanding of age-related decline in mnemonic discrimination can also inform basic models of memory. This thesis evaluated the contribution of encoding processes to mnemonic discrimination both in young adults and in ageing, within the framework of two prominent accounts of recognition memory, the pattern separation account (Wilson et al., 2006) and Fuzzy Trace Theory (FTT; Brainerd & Reyna, 2002). Firstly, a functional magnetic resonance imaging study in young adults found evidence for differences in regions engaged at encoding of images according to the accuracy of later mnemonic discrimination, consistent with both pattern separation and FTT. Evidence of functional overlap between regions showing activity consistent with pattern separation, and activity associated with later accurate recognition was consistent with a role of cortical pattern separation in successful encoding, but there was no direct evidence that cortical pattern separation contributed to mnemonic discrimination. This first evidence of cortical pattern separation in humans was supported by findings that in the majority of pattern separation regions, response functions to stimuli varied in their similarity to previous items were consistent with predictions of computational models. Regional variation in the dimension(s) of similarity (conceptual/perceptual) driving pattern separation was indicative of variation in the type of mnemonic interference minimised by cortical pattern separation. Further evidence of encoding contributions to mnemonic discrimination was provided by an event-related potential study in young and older adults. Older adults showed less distinct waveforms than young adults at encoding of items whose similar lures were later correctly rejected compared to those falsely recognised, supporting the proposal that age-related encoding impairments contribute to the decline in mnemonic discrimination. Finally, a set of behavioural studies found that older adults’ mnemonic discrimination deficit is increased by conceptual similarity, supporting previous findings and consistent with FTT’s account of greater emphasis by older adults on gist processing. However, older adults required greater reduction in perceptual or conceptual similarity in order to successfully reject lures, as uniquely predicted by the pattern separation account. Together, the findings support the notion that encoding processes contribute directly to mnemonic discrimination and its age-related decline. An integrated view of the pattern separation account and FTT is discussed and developed in relation to the current findings.

This study examined whether schemas formed during training (graduate coursework, clinical supervision, etc.) are responsible for the tendency of clinicians to experience higher rates of false recall for clinical case details when compared to novices. Participants in this study were recruited from a general psychology class to limit preexisting knowledge of psychological disorders. Half of the participants were trained to recognize features of Generalized Anxiety Disorder with the purpose of forming a schema for that disorder, whereas the other half were not. Participants’ memory for the diagnostic and non-diagnostic details within a hypothetical case vignette was tested using a free recall prompt followed by a yes/no recognition test. Trained participants falsely recognized the diagnostic detail ‘restlessness’ and falsely recalled the diagnostic detail ‘uncontrollable worry’ at a significantly higher rate than controls, suggesting that the training successfully formed a schema for GAD symptoms.

ABSTRACT OF THE DISSERTATION OF Yonglian Wang, for Doctor of Philosophy degree in Electrical and Computer Engineering, presented on May 19, 2009, at Southern Illinois University- Carbondale. TITLE: SPEECH RECOGNITION UNDER STRESS MAJOR PROFESSOR: Dr. Nazeih M. Botros In this dissertation, three techniques, Dynamic Time Warping (DTW), Hidden Markov Models (HMM), and Hidden Control Neural Network (HCNN) are utilized to realize talker-independent isolated word recognition. DTW is a technique utilized to measure the distance between two input patterns or vectors; HMM is a tool utilized to model speech signals using stochastic process in five states to compare the similarity between signals; and HCNN calculates the errors between actual output and target output and it is mainly built for the stress compensated speech recognition. When stress (Angry, Question and Soft) is induced into the normal talking speech, speech recognition performance degrades greatly. Therefore hypothesis driven approach, a stress compensation technique is introduced to cancel the distortion caused by stress. The database for this research is SUSAS (Speech under Simulated and Actual Stress) which includes five domains encompassing a wide variety of stress, 16,000 isolated-word speech signal samples available from 44 speakers. Another database, called TIMIT (10 speakers and 6300 sentences in total) is used as a minor in DTW algorithm. The words used for speech recognition are speaker-independent. The characteristic feature analysis has been carried out in three domains: pitch, intensity， and glottal spectrum. The results showed that speech spoken under angry and question stress indicates extremely wide fluctuations with average higher pitch, higher RMS intensity, and more energy compared to neutral. In contrast, the soft talking style has lower pitch, lower RMS intensity, and less energy compared to neutral. The Linear Predictive Coding (LPC) cepstral feature analysis is used to obtain the observation vector and the input vector for DTW, HMM, and stress compensation. Both HMM and HCNN consist of training and recognition stages. Training stage is to form references, while recognition stage is to compare an unknown word against all the reference models. The unknown word is recognized by the model with highest similarity. Our results showed that HMM technique can achieve 91% recognition rate for Normal speech; however, the recognition rate dropped to 60% for Angry stress condition, 65% for Question stress condition, and 76% for Soft stress condition. After compensation was applied for the cepstral tilts, the recognition rate increased by 10% for Angry stress condition, 8% for Question stress condition, and 4% for Soft stress condition. Finally, HCNN technique increased the recognition rate to 90% for Angry stress condition and it also differentiated the Angry stress from other stress group.

There is evidence of false recognition (FR) driven by orthographic similarities within languages (Lambert, Chang, & Lin, 2001; Raser, 1972) and some evidence that FR crosses languages (Parra, 2013). No study has investigated whether FR based on orthographic similarities occurs for unknown words in an unknown language. This study aimed to answer this question. It further explored whether FR based on orthographic similarities is more likely in a known (English) than in an unknown (Spanish) language. Forty-six English monolinguals participated. They studied 50 English and 50 Spanish words during a study phase. A recognition test was given immediately after the study phase. It consisted of 40 Spanish and 40 English words. It included list words (i.e., words presented at study); homographs (i.e., words not presented at study, orthographically similar to words presented at study); and unrelated words (i.e., words not presented at study, not orthographically similar to words presented at study). The LSD post-hoc test showed significant results supporting the hypothesis that false recognition based on orthographic similarities occurs for words in a known language (English) and in an unknown language (Spanish). Further evidence was provided by the LSD post-hoc test supporting the hypothesis that false recognition based on orthographic similarities was more likely to occur in a known language than an unknown language. Results provided evidence that the meaning and orthographic form are used when information is encoded thereby influencing recognition decisions. Furthermore, these results emphasize the significance of orthography when information is encoded and retrieved.

<p>This thesis presents four studies investigating (1) whether incidentally primed control-related words can attenuate the impact of activated stereotypes on subsequent evaluation of a target person, (2) the impact of motivated forgetting on the recall of stereotypically congruent and incongruent information, and (3) the impact of a directed forgetting instruction on the false recall and recognition of nonpresented stereotypical information.</p><p>In three experiments, Study I showed that participants initially primed with the social category, <i>immigrant, </i>and subsequently primed with words that were evocative of control or self-control made less negative impression of a target displaying ambiguous behaviors than participants not exposed to such words.</p><p>Study II, using a directed-forgetting paradigm, demonstrated in two experiments that participants subliminally primed with Swedish facial photographs who later studied stereotypically incongruent words roughly recalled an equal number of items regardless of the forget or remember instructions. </p><p>Study III showed that participants primed with the social category, <i>immigrant</i> and then studied a list of stereotypically related and unrelated words falsely recognized more nonpresented stereotypical words when they were furnished with a forget than a remember instruction. Similarly, Study IV (Experiment 2) demonstrated that participants primed with the social category, <i>immigrant</i>, but not with a neutral category, falsely recalled more nonpresented stereotypical words when their cognitive capacity was depleted through a concurrent memory load task. </p><p>The thesis presents a review and a discussion of some of the theoretical underpinnings of the extant literature on stereotyping and intergroup relations and of the social implications of the present findings.</p>

This thesis presents four studies investigating (1) whether incidentally primed control-related words can attenuate the impact of activated stereotypes on subsequent evaluation of a target person, (2) the impact of motivated forgetting on the recall of stereotypically congruent and incongruent information, and (3) the impact of a directed forgetting instruction on the false recall and recognition of nonpresented stereotypical information. In three experiments, Study I showed that participants initially primed with the social category, immigrant, and subsequently primed with words that were evocative of control or self-control made less negative impression of a target displaying ambiguous behaviors than participants not exposed to such words. Study II, using a directed-forgetting paradigm, demonstrated in two experiments that participants subliminally primed with Swedish facial photographs who later studied stereotypically incongruent words roughly recalled an equal number of items regardless of the forget or remember instructions. Study III showed that participants primed with the social category, immigrant and then studied a list of stereotypically related and unrelated words falsely recognized more nonpresented stereotypical words when they were furnished with a forget than a remember instruction. Similarly, Study IV (Experiment 2) demonstrated that participants primed with the social category, immigrant, but not with a neutral category, falsely recalled more nonpresented stereotypical words when their cognitive capacity was depleted through a concurrent memory load task. The thesis presents a review and a discussion of some of the theoretical underpinnings of the extant literature on stereotyping and intergroup relations and of the social implications of the present findings.

Depuis ces deux dernières décennies, des efforts considérables en psychologie cognitive et neuropsychologie ont été déployés pour mieux comprendre les dynamiques entre les différents systèmes cognitifs (fonctions exécutives, mémoire, langage, etc.). L’observation d’une co-existence entre des atteintes en rétention à court terme verbale (RCTv) et en langage dans plusieurs pathologies a conduit certains chercheurs à concevoir une alternative à la conceptualisation classique de la RCTv, telle que proposée par le modèle initial de la mémoire de travail de Baddeley (1986). Particulièrement, les travaux sur l’aphasie ont conduit à l’émergence d’une approche psycholinguistique de la RCTv, postulant que le traitement et le maintien des mots font appel à des processus communs. Cette approche, et particulièrement le modèle d’activation interactive (N. Martin & Gupta, 2004; N. Martin & Saffran, 1997), prédit que les capacités en RCTv sont notamment modulées par les caractéristiques linguistiques engagées durant l’épreuve, variant selon la nature des items verbaux et la modalité de rappel, ainsi que par les compétences linguistiques des individus. L’objectif de la présente thèse était de tester ces prédictions à partir d’une exploration des relations entre le traitement sémantique des mots et la RCTv chez l’adulte sain (article 1) et dans la démence de type Alzheimer (DTA) (article 2). Dans le premier article, deux expériences mettent en évidence l’influence des liens associatifs entre les mots sur les capacités à maintenir temporairement des informations verbales. Les participants ont tendance à faussement reconnaître des mots associés aux mots de la liste, reflet d’une activation du réseau sémantique durant la rétention temporaire. Cette contribution sémantique est accentuée en situation de suppression articulatoire, une condition qui empêche le participant de répéter les listes durant la tâche. Les résultats du second article indiquent que la modalité de réponse module différemment la performance en RCTv chez les participants âgés sans atteinte neurologique et ceux atteints de la DTA. Ces données en RCTv sont compatibles avec les atteintes spécifiques du traitement du mot, également trouvées chez le groupe avec DTA. Les implications théoriques et cliniques de ces résultats sont discutées. Les limites et perspectives futures sont également abordées. / For the past two decades, considerable efforts have been made in cognitive psychology and neuropsychology in order to improve our understanding of the interactions between different cognitive systems (executive functions, memory, language etc.). Evidence of short-term memory (STM) and language impairments in many clinical populations has lead some researchers to put forward an alternative to Baddeley’s working memory model (1986). Based on studies of aphasia, the psycholinguistic approach of STM postulated that word processing and maintenance refer to common processes. Specifically, the interactive activation model (N. Marin & Gupta, 2004; N. Martin & Saffran, 1997) predicts that STM capacities are in particular affected by the linguistic characteristics engaged during the test, and vary according to the nature of verbal items and recall modality, as well as word processing ability. The goal of this thesis was to test some of these predictions by investigating the relationship between semantic treatment and STM in healthy adults (article 1) and dementia of Alzheimer Type (DAT) (article 2). In the first article, two experiments underline the influence of the associative links between words on the capacity to temporarily retain verbal information. Participants tend to wrongly recognize words associated with words from the list, reflecting an activation of the semantic network during temporary retention. This semantic contribution increases in a situation of articulatory suppression, a condition that limits the possibility to repeat lists during the task. The results of the second article indicated that recall modality influences differently the performance in STM of the elderly participants and those with DAT. These data in STM are compatible with a specific word processing impairment, also found in the group with DAT. The theoretical and clinical implications of these results are discussed. Limits and future research perspectives are also presented.