In a world dominated by temporal order, memory capable of processing, encoding and subsequently recalling ordered information is very important. Over the decades this memory, known as serial memory, has been extensively studied, and its effects are well known. Many models have also been developed, and while these models are able to reproduce the behavioural effects observed in human recall studies, they are not always implementable in a biologically plausible manner. This thesis presents the Ordinal Serial Encoding model, a model inspired by biology and designed with a broader view of general cognitive architectures in mind. This model has the advantage of simplicity, and we show how neuro-plausibility can be achieved by employing the principles of the Neural Engineering Framework in the model’s design. Additionally, we demonstrate that not only is the model able to closely mirror human performance in various recall tasks, but the behaviour of the model is itself a consequence of the underlying neural architecture.

Objectives: The aim of the two exploratory studies presented here, was to investigate expert-novice cognitive performance in the field of dietetic counseling. More specifically, the purpose was to characterize the knowledge used and the cognitive reasoning strategies of expert, intermediate and novice dietitians during their assessment of clinical vignettes of simulated dyslipidemia cases. Background: Since no studies have been conducted on the expert-novice differences in knowledge utilization and reasoning in the field of dietetics, literature from various domains looking at expert-novice decision-making was used to guide the studies presented here. Previous expert-novice research in aspects of health such as counseling and diagnostic reasoning among physicians and nurses has found differences between in the way experts extract and apply knowledge during reasoning. In addition, various studies illustrate an intermediate effect, where generalist performance is somewhat poorer than that of experts and novices. Methods: The verbal protocols of expert (n=4), generalist (n=4), and novice (n=4) dietitians were analyzed, using propositional analysis. Semantic networks were generated, and used to compare reasoning processes to a reference model developed from an existing Dyslipidemia care map by Brauer et al, (2007, 2009). Detailed analysis was conducted on individual networks in an effort to obtain better understanding of cue utilization, concept usage, and overall cohesiveness during reasoning. Results: The results of the first study indicate no statistical differences in reasoning between novices, generalist and experts with regards to recalls and inferences. Interesting findings in the study also suggest that discussions of the terms “dietary fat” and “cholesterol” by individuals in each level of expertise had qualitative differences. This may be reflective of the information provided in the case scenearios to each participating dietitian. Furthermore, contrary to previous studies in expert-novice reasoning, an intermediate effect was not evident. The results of the second study show a statistical difference in data driven (forward) reasoning between experts and novices. There was no statistical difference in hypothesis driven (backward) reasoning between groups. The reasoning networks of experts appear to reveal more concise explanations of important aspects related to dyslipidemia counseling. Reasoning patterns of the expert dietitians appear more coherent, although there was no statistical difference in the length or number of reasoning chains between groups. With previous research focusing on diagnostic reasoning rather than counseling, this finding may be a result of the nature of the underlying task. Conclusion: The studies presented here serve as a basis for future expert-novice research in the field of dietetics. The exploration of individual verbal protocols to identify characteristics of dietitians of various levels of expertise, can provide insight into the way knowledge is used and applied during diet counseling. Subsequent research can focus on randomized sample selection, with case scenarios as a constant, in order to obtain results that can be generalized to the greater dietitian population.

The thesis investigated the importance of cognition for speech understanding in experienced and new hearing aid users. The aims were 1) to develop a cognitive test (Sentence-final Word Identification and Recall, or SWIR test) to measure the effects of a noise reduction algorithm on processing of highly intelligible speech (everyday sentences); 2) to investigate, using the SWIR test, whether hearing aid signal processing would affect memory for heard speech in experienced hearing aid users; 3) to test whether the effects of signal processing on the ability to recall speech would interact with background noise and individual differences in working memory capacity; 4) to explore the potential clinical application of the SWIR test; and 5) to examine the relationship between cognition and speech recognition in noise in new users over the first six months of hearing aid use. Results showed that, for experienced users, noise reduction freed up cognitive resources and alleviated the negative  impact of noise on memory when speech stimuli were presented in a background of speech babble spoken in the listener’s native language. The possible underlying mechanisms are that noise reduction facilitates auditory stream segregation between target and irrelevant speech and reduces the attention captured by the linguistic information in irrelevant speech. The effects of noise reduction and SWIR performance were modulated by individual differences in working memory capacity. SWIR performance was related to the self-reported outcome of hearing aid use. For new users, working memory capacity played a more important role in speech recognition in noise before acclimatization to hearing aid amplification than after six months. This thesis demonstrates for the first time that hearing aid signal processing can significantly improve the ability of individuals with hearing impairment to recall highly intelligible speech stimuli presented in babble noise. It also adds to the literature showing the key role of working memory capacity in listening with hearing aids, especially for new users. By virtue of its relation to subjective measures of hearing aid outcome, the SWIR test can potentially be used as a tool in assessing hearing aid outcome. / Avhandlingens övergripande mål var att studera kognitionens betydelse för talförståelse hos vana och nya hörapparatsanvändare. Syftena var att 1) utveckla ett kognitivt test (Sentence-final Word Identification and Recall, eller SWIR test) för att mäta en brusreducerande algoritms effekt på bearbetningen av tydligt tal (vardagsmeningar); 2) att med hjälp av SWIR testet undersöka huruvida hörapparatens signalbehandling påverkade återgivningen av uppfattat tal hos vana hörapparatsanvändare; 3) att utvärdera om effekten av signalbehandling på förmågan att komma ihåg tal påverkas av störande bakgrundsljud samt individuella skillnader i arbetsminnets kapacitet; 4) att undersöka den potentiella kliniska tillämpningen av SWIR testet och 5) att undersöka förhållandet mellan kognition och taluppfattning i störande bakgrundsljud hos nya hörapparatsanvändare under de första sex månaderna med hörapparater. Resultaten visade att för vana hörapparatsanvändare lindrade brusreduceringen det störande ljudets negativa inverkan på minnet när meningar presenterades i form av irrelevant tal på deltagarnas modersmål. De möjliga underliggande mekanismerna är att brusreducering underlättar diskriminering av de auditiva informationsflödena mellan det som ska uppfattas och det som är irrelevant, samt minskar graden av uppmärksamhet som fångas av den språkliga informationen i det irrelevanta talet. Effekterna av brusreducering och resultaten av SWIR var beroende av individuella skillnader i arbetsminnets kapacitet. Resultaten av SWIR har också samband med det självrapporterade utfallet av  hörapparatsanvändning. För nya användare spelar arbetsminnets kapacitet initialt en viktigare roll för taluppfattning i störande bakgrundsljud, innan anpassningen till hörapparatens förstärkning skett, än efter sex månader. Denna avhandling visar för första gången att hörapparatens signalbehandling kan signifikant förbättra möjligheten för individer med hörselnedsättning att minnas tydligt tal, som presenteras i störande bakgrundsljud. Avhandlingen bidrar till litteraturen med en diskussion om hur arbetsminnets kapacitet spelar roll i taluppfattning med hörapparat, i synnerhet för nya användare. Med stöd av dess samband med det självrapporterade utfallet, kan SWIR testet användas som redskap i bedömning av hörapparaters effekt.

A decision to recall products by firms can lead to negative consequences such as erosion of shareholder wealth and loss of customer goodwill. Further, the way a recall is managed can lead to more negative consequences than the recall decision itself. Therefore the manner in which firms manage such decisions can help mitigate these negative consequences. This thesis examines two such decisions: recall restitution and time to recall. A firm’s decisions on restitution offered to affected customers and time to recall may evoke conflicting reactions from shareholders and customers, where serving the interests of one stakeholder affects the interests of the other. While higher restitutions and faster recalls improve customer goodwill, they lead to erosion of shareholder wealth. This finding is used to hypothesize the influence of organizational characteristics (position of the firm in the value chain, firm’s internal operations, and firm’s recall experience), and key crisis factors (ambiguity and severity) on these decisions. This thesis uses data on toy recalls issued in the U.S. from 1988 to 2011. The results show that firms tend to favor shareholders by offering lower restitutions to affected customers when they are situated farther from the customer in the supply chain, when they have more experience with recalls, when the crisis is severe, and when the cause of the crisis is ambiguous. When the recall is due to the internal operations of the firm, restitution offered to affected customers is lower only when the severity of the recall is high. Firms issue recalls quickly when the crisis is severe in order to reduce customer hazards and avoid negative publicity. Severe recalls, however, may be delayed when firms are experienced in recall management, and when such recalls are caused by the internal operations of the firm. The findings of this thesis highlight one of the dilemmas that firms face in a crisis decision making situation and help foster an understanding of the conditions under which firms manage shareholder versus customer reactions in order to mitigate the negative consequences of recall management decisions.

This study examined the recall of televised stories for younger (4-6 years) and older (7-9 years) children with and without ADHD under two different viewing conditions (toys present/toys absent). Each child watched two Rugrats television programs, once with toys present and once with toys absent. Immediately after viewing a program, the child completed a free recall of the observed story. Nonreferred childrens recall increased more than ADHD childrens as importance level increased, and older nonreferred children recalled more information overall than older children with ADHD. For the toys condition, children with ADHD had smaller correlations between the story units recalled and the order of these units in the story than did nonreferred children. Children with ADHD demonstrated multiple difficulties in story comprehension. They were less sensitive to thematic importance and they produced less coherent recalls than their nonreferred peers.

Learning occurs not only when we encode information but also when we test our memory for this information at a later time. In three empirical studies, I investigated the individual and combined effects of interleaved testing (via repeated rounds of study and test practice) and encoding (via motor enactment) during learning on later cued-recall performance for action phrases. Such materials (e.g., “water the flowers”) contain a verb and a noun and approximate everyday memory that typically revolves around past and future actions. Study I demonstrated that both interleaved testing (vs. study only) and enactment (vs. verbal encoding) individually reduced the forgetting rate over a period of 1 week, but these effects were nonadditive. That is, the direct testing effect on the forgetting rate occurred for verbal, but not for enactive encoding; enactment reduced the forgetting rate for the study-only condition, but not for the study–test condition. A possible explanation of these findings is that both study techniques sufficiently elicit verb–noun relational processing that cannot be increased further by combining them. In Studies II and III, I replicated these testing-effect results and investigated whether they varied as a function of recall type (i.e., noun-cued recall of verbs and verb-cued recall of nouns). For verbal encoding (Study II), the direct testing effect was of similar size for both noun- and verb-cued recall. For enactive encoding, the direct testing effect was lacking irrespective of recall type. In addition, interleaved tests enhanced subsequent re-encoding of action phrases, leading to an accelerated learning. This indirect testing effect was increased for the noun-cued recall of verbs—for both verbal and enactive encoding. A possible explanation is that because nouns are semantically more stable, in that the meaning of nouns changes less over time and across different contexts, they are more recognizable. Hence, associated information (e.g., about the recall status) may be more available to the learner during restudy that, in turn, can initiate more effective re-encoding. The two different testing benefits (i.e., direct and indirect) may, partly, engage different mechanisms, as they were influenced differentially by the manipulations of encoding type and recall type. The findings presented in the thesis provide new knowledge regarding the combined effects of strategies and materials that influence memory. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1. Epub ahead of print. Paper 2: Manuscript. Paper 3: Manuscript.</p>

A decision to recall products by firms can lead to negative consequences such as erosion of shareholder wealth and loss of customer goodwill. Further, the way a recall is managed can lead to more negative consequences than the recall decision itself. Therefore the manner in which firms manage such decisions can help mitigate these negative consequences. This thesis examines two such decisions: recall restitution and time to recall. A firm’s decisions on restitution offered to affected customers and time to recall may evoke conflicting reactions from shareholders and customers, where serving the interests of one stakeholder affects the interests of the other. While higher restitutions and faster recalls improve customer goodwill, they lead to erosion of shareholder wealth. This finding is used to hypothesize the influence of organizational characteristics (position of the firm in the value chain, firm’s internal operations, and firm’s recall experience), and key crisis factors (ambiguity and severity) on these decisions. This thesis uses data on toy recalls issued in the U.S. from 1988 to 2011. The results show that firms tend to favor shareholders by offering lower restitutions to affected customers when they are situated farther from the customer in the supply chain, when they have more experience with recalls, when the crisis is severe, and when the cause of the crisis is ambiguous. When the recall is due to the internal operations of the firm, restitution offered to affected customers is lower only when the severity of the recall is high. Firms issue recalls quickly when the crisis is severe in order to reduce customer hazards and avoid negative publicity. Severe recalls, however, may be delayed when firms are experienced in recall management, and when such recalls are caused by the internal operations of the firm. The findings of this thesis highlight one of the dilemmas that firms face in a crisis decision making situation and help foster an understanding of the conditions under which firms manage shareholder versus customer reactions in order to mitigate the negative consequences of recall management decisions.

Auditory sequencing ability was studied in 18 five and 18 nine year old normal-hearing children, and in 18 hearing-impaired children aged 6 to 14 years. Subjects selected were able to repeat syllables differing in initial consonant or final vowel and identify pictures corresponding to 200-msec. environmental sounds. Sequences of 2, 3 and 4 such items were recorded at 1, 2 and 4 items per second. Significant interactions between type of stimuli, sequence length and rate were obtained. Normal-hearing children and, to a lesser extent, hearing-impaired children had greater facility in recalling verbal than nonverbal sequences. For aIl groups, the fastest rate was optimal for consonants, and the slowest rate for nonverbal sounds. Normal children were superior to hearing-impaired subjects on verbal sequences. On nonverbal sequences, hearing-impaired were more accurate than normal five year olds, but less accurate than nine year olds. Implications for auditory training are discussed. / L'habilite de suivre un ordre auditif fut étudiee chez des enfants d'audition normale de cinq et neuf ans et chez des sujets atteints de surdite, ages de 6 à 14 ans, 18 pour chaque groupe. Les sujets choisis pouvaient repeter des syllabes enregistrees, identifier des images correspondant à des sons d'entourage de 200 msec. de duree. Des ordres de 2, 3 et 4 de ces stimuli furent enregistrés au rythme de 1, 2 et 4 stimuli par seconde. Les enfants d'audition normale et, d'une façon moins eVidente, les enfants atteints de surdité avaient une plus grande facilite à se rappeler des ordres verbaux plutôt que non-verbaux. Pour tous les groupes, la vitesse la plus rapide fut optimale pour les consonnes, et la vitesse la plus lente, pour les sons non-verbaux. Les sujets d'audition normale furent superieurs à ceux atteints de surdité, pour les ordres verbaux mais ces derniers, furent supérieur aux sujets ages de cinq ans et non pas de neuf ans, pour les ordres non-verbaux. Des implications pour l'entraînement auditif sont discutes. fr

The giant panda (Ailuropoda melanoleuca) is an endangered species and many efforts are being made to ensure its survival, including numerous research studies. However, there has been little investigation of spatial memory in the giant panda. Spatial memory is an important mechanism for survival in the wild, allowing an animal to find and remember the location of food, mates, den sites and avoid predators. Memory assessment in non-human species typically involves the use of recognition, as opposed to recall tasks. The current study tested spatial memory recall in 1.1 giant pandas using a delayed response memory task. The design required a delayed response to a previously lighted location, with varying lengths of delay between the observation phase and the test phase. The male subject reached criterion at 2-, 3-, 4-, 5-, 6-, and 10-second delays. The female subject reached criterion at 2-, 3-, 4-, 5-, 6-, 10-, and 15-second delays. The results support the hypothesis that giant pandas have working memory recall ability for spatial location.

This thesis investigated the effects of eyewitnesses retellings and discussions with non-witnesses on the eyewitness memory and meta-memory judgments. In Study I, the effect of eyewitness discussions with non-witnesses (persons who had not experienced the event) on eyewitness memory and meta-memory realism for the overall information about an event was investigated. The results suggest that discussions of an experienced event may reduce some of the beneficial memory and meta-memory effects caused by mere retellings, but may not have great negative effects compared to a control condition. Analysis of the type of questions asked suggests listeners ask more about the peripheral details as compared with the central details. In a follow-up study to study I conducted a year later participants in the Retell condition no longer showed evidence of the memory and meta-memory benefits evident at the original final test after about 24 days. However, participants in the Retell condition recalled a higher number of correct items than participants in the Control condition. In Study II, the effect of eyewitness discussions with non-witnesses on eyewitness memory and meta-memory realism for different types of information was investigated. The different types of information were Forensically central, Forensically peripheral, and Non-forensic information. These are types of information that the police may ask at the beginning of a crime investigation. The results from the two experiments showed that participants had better memory and meta-memory realism for Forensically central and Non-forensic information than for Forensically peripheral information. Moreover, participants in the four conditions were equally capable of distinguishing between correct and incorrect items. Further, in Experiment 1 participants in conditions involving retelling and discussing the event reported more total number and number of correct Forensically central items as compared to the Control condition. Study III investigated if retellings and discussions would cause more reminiscence and hypermnesia than mere retellings. The results showed that discussions indeed cause more reminiscence and hypermnesia over the five sessions as compared to mere retellings. The results also showed that the number of times a piece of in- formation was repeated over the sessions was associated with a higher probability for that piece of information being retrieved at the final recall. Interestingly, if the information was retold or discussed in an earlier or later session did not predict if this information would be reported in the testing session or not. Last, the results showed that the forensically peripheral information, but not forensically central information was affected by the reiteration effect (i.e., the effect that confidence tends to increase when a person asserts the same statement many times). This may be due to the fact that the peripheral information was less integrated than the central information. / Det är vanligt att ögonvittnen återger och diskuterar en upplevd brottshändelse med sin familj och vänner. Syftet med dessa diskussioner är att uppdatera familj och vänner om vad som är nytt. Dessa diskussioner har konsekvenser för ögonvittnets senare minnesrapportering och meta-minnesbedömningar. Med minnesrapportering menas här vad ett ögonvittne kan återerinra sig om den bevittnade händelsen och med meta-minnesbedömningar menas ögonvittnets känslor av säkerhet på att hans/hennes minnen av händelsen är korrekta. Vittnens meta-minnesbedömningar kallas nedan konfidensbedömningar. Med uttrycket ”god realism” i meta-minnesbedömningarna menas att nivån på vittnets konfidensbedömningar matchar nivån på korrektheten i vittnets minnesrapportering av den upplevda händelsen. Vittnets minnesrapportering och konfidensbedömningar av sina rapporterade minnen är viktig information i kriminaltekniska sammanhang. Minnet hjälper oss att förstå detaljerna i brottshändelsen och vittnets konfidensbedömningar ger hjälp att förstå korrektheten av dessa minnen. Denna avhandling har undersökt effekterna av att ögonvittnen återberättar och diskuterar (en filminspelning av) en upplevd brottshändelse med icke-vittnen (personer som inte upplevt händelsen) på ögonvittnens minnesrapportering och på deras konfidensbedömningar av de rapporterade minnena. I Studie I fick deltagarna först se en kort film (c:a 4 minuter) och därefter fem gånger över en tre-veckorsperiod uppdelade i tre betingelser antingen enbart fick återberätta händelsen eller både återberätta och diskutera händelsen med icke-vittnen (antingen i en laboratoriemiljö eller med familjemedlemmar och vänner). Lyssnarna var nya personer i var och en av de fem sessionerna. Dessa tre försöksbetingelser jämfördes mot en kontrollbetingelse där dessa aktiviteter inte skedde. Alla deltagarna genomförde en avslutande sjätte testsession där vittnena fick instruktionen att återberätta allt vad de kan minnas av den upplevda händelsen (dvs öppen fri framtagning) och tre dagar senare ge konfidensbedömningar av de olika ingående elementära minneutsagorna i de rapporterade minnena. Av intresse i studien var alltså effekten av upprepat återberättande och diskussioner av en upplevd händelse på ögonvittnens minnesrapportering och på realismen i vittnenas konfidensbedömningar i den avslutande sjätte testsessionen. Resultaten tyder på att diskussioner om en upplevd händelse kan minska några av de positiva effekterna på kvalitén i minnesrapporteringen och på realismen i meta-minne som orsakas av enbart återberättande, men att diskussionerna inte får stora negativa effekter jämfört med en kontrollbetingelse där återberättande och diskussioner av händelsen inte skett. Analys av vilken typ av frågor lyssnarna ställde visade att man frågade mer om de perifera detaljerna i händelsen, jämfört med händelsens centrala detaljer (i första hand handlingar). En uppföljande studie till studie I genomfördes ett år senare. Denna studie visade inga kvarstående tecken på de fördelar på minnesrapportering och meta-minne som deltagarna i den betingelse som enbart återberättat händelsen fem gånger uppvisade i slutsessionen i Studie I efter c:a 24 dagar. Däremot hade deltagarna, i den betingelse som enbart återberättat händelsen, efter ett år ett högre antal korrekta minnesrapporterade utsagor jämfört med deltagarna i kontrollbetingelsen. Studie II utgick delvis från samma data som i Studie I. Här undersöktes effekten av ögonvittnens diskussioner med icke-vittnen på ögonvittnens minne och meta-minne realism för olika typer av information. De olika typer av information som analyserades var Forensiskt central, Forensiskt perifer och Icke-forensiskt relevant information. De två Forensiskt relevanta informationstyperna är sådan information som det är troligt att polisen kan vilja ha i början av en brottsutredning. Resultaten från de två experimenten i Studie II visade att deltagarna hade bättre minne och meta-minne realism för Forensiskt central och för Icke-forensiskt relevant information än för Forensiskt perifer information. Dessutom var deltagarna i de fyra betingelserna i Experiment I (samma fyra betingelser som i Studie I) lika kapabla att skilja mellan korrekt och inkorrekt objekt med hjälp av nivån på sina konfidensbedömningar för alla tre informationstyperna. Experiment 1 i Studie II visade också att deltagarna i de betingelser där deltagarna återberättade och diskuterade händelsen rapporterade ett högre antal korrekta Forensiskt centrala minnesutsagor jämfört med kontrollbetingelsen. Studie III gällde data från två av betingelserna i Studie I, närmare bestämt inspelade data från de fem återgivningsomgångarna i den betingelse där deltagarna enbart återberättat händelsen och inspelade data från den betingelse där deltagarna både återberättade och diskuterade händelsen i laboratoriet. Studien visade att deltagarna i den betingelse där deltagarna både återgav och diskuterade händelsen uppvisade mer reminiscens (fler minnesutsagor, både korrekta och inkorrekta över de fem sessionerna) och mer hypermnesi (tillskott av mer korrekta minnesutsagor över de fem sessionerna) än deltagarna i den betingelse där de bara återberättade händelsen fem gånger över tre veckor. Resultaten visade också att antalet gånger en minnesutsaga upprepades under sessionerna var förenat med en högre sannolikhet för att minnesutsagan skulle återges vid den slutliga återgivningen. Däremot hade det, intressant nog, ingen effekt om minnesutsagorna hade återberättats eller diskuterats i en tidigare eller senare session (av de 5 sessionerna) på om minnesutsagan skulle redovisas i den sjätte testsession eller inte. Slutligen visade resultatet i Studie III att de Forensiskt perifera minnesutsagorna, men inte de Forensiskt centrala utsagorna, uppvisade en så kallad reitereringseffekt vilken innebär att säkerhetskänslan (dvs upplevd konfidens att utsagan är korrekt) höjs som en effekt av att utsagan upprepas fler gånger. Detta kan bero på att den Forensiskt perifera informationen är mindre välintegrerad än den Forensiskt centrala informationen.