人們對於錯誤訊息處理經由自我覺察或外在回饋之管道，可藉由事件關聯電位分別測得ERN (error-related negativity) 及FRN (feedback-related negativity)。過去研究曾指出雙側作業(Flanker task)中錯誤所引發的ERN會受到以圖片呈現的短期情緒所調節，然而對於回饋誘發的FRN與個體情緒調節的關係則未曾被探討過。過去FRN的研究認為唯有當受試者所進行的作業為增強學習作業時，受試者對於回饋結果的預期狀態才能反映於FRN的反應強度。本研究利用兩個實驗分別採用非增強學習作業及增強學習作業，其中並以IAPS情緒圖片進行短期情緒的引發，在受試者於實驗中對其反應結果的不同預期狀態，探測受試者FRN受短期情緒調節的效果。 實驗一利用非增強學習作業，結果顯示FRN的強度可以反映受試者對於回饋結果的預期狀態，其中以非預期時FRN的強度為最大，預期時FRN的強度為最小；另外，正向情緒圖片對於FRN具有調節效果，正向情緒下FRN反應強度小於中性以及負向情緒下FRN反應強度。實驗二利用增強學習作業，前述的FRN強度反映受試者對回饋結果的預期效果，只有在實驗前半段的嘗試次中被觀測到，此效果未見於全部嘗試次納入分析；另外，實驗二中沒有觀察到情緒對於FRN的調節效果。 綜合而言，本研究發現受試者唯有持續處於學習的情形下，FRN才能反映受試者對於回饋結果的預期狀態，情緒對FRN的調節效果也僅於此情況下才能被觀測到。 / Error-related information in human can be processed via self-awareness and/or feedback given externally, which are measurable by the use of event-related potential (ERP) and termed error-related negativity (ERN) and feedback-related negativity (FRN) respectively. Previous studies showed that short-term affective stimuli would modulate the magnitude of ERN elicited by Flanker task. However, such modulation effect has not been tested on FRN. Furthermore, the magnitude of FRN is indicated to be related to the expectancy states toward feedback when the subject is undergoing a reinforcement learning task. Present study, thus, was designed to test the affective modulation effect on FRN in two separate tasks. In which, emotional pictures adopted from IAPS were used as the short-term affective stimuli, and different expectancy states in both non-reinforcement learning task (Experiment1) and reinforcement learning task (Experiment 2) were manipulated. In the results of Experiment 1, the magnitude of FRN was larger under the unexpected condition in comparing to the expected one. Modulation effect of short-term affective stimuli on FRN was obtained when positive emotion pictures were presented in non-reinforcement learning task, which FRN amplitude was significantly smaller in comparing to those measured after the presentation of neutral and negative pictures. In the results of Experiment 2, FRN elicited in the unexpected condition was only obtained from analyzing the dada collected in the first half of trails. Such effect was not confirmed when the data from all trials were analyzed. A lack of modulation effect of short-term affective stimuli on FRN appeared in Experiment 2. In conclusion, it is indicated that the expectancy depended FRN is most apparent when the subject is undergoing a continuous learning-demanded process. Meanwhile, short-term affective stimuli can modulate such FRN.

My dissertation aims to contribute to a more comprehensive understanding of how consumers make sense of online word-of-mouth. Each essay in my dissertation probes beyond the effect of rating valence and explores the role of textual content. In the first essay, I explore negativity bias among online consumers evaluating peer information about potential sellers. I propose that both the likelihood of negativity bias and resistance to change after a trust violation will depend on the domain of information discussed in a review. Three experiments showed that negativity bias is more prominent for information regarding sellers' integrity than information regarding their competence. These findings suggest that the universality of negativity bias in a seller review setting has been exaggerated. In the second essay, I examine the impact of emotional arousal on the perceived helpfulness of text reviews. I propose an inverse U-shaped relationship by which the arousal conveyed in a text review will be associated by readers with lower perceived helpfulness only beyond an optimal level, and that the detrimental effect of arousal is present for negative reviews even when objective review content is controlled for. To test these hypotheses, two studies were conducted in the context of Apple's mobile application market. In Study 1, I collected actual review data from Apple's App Store, coded those reviews for arousal using text analysis tools, and examined the non-linear relationship between arousal and review helpfulness. In Study 2, I experimentally manipulated the emotional arousal of reviews at moderate to high levels while holding objective content constant. Results were largely consistent with the hypotheses. This essay reveals the necessity of considering emotional arousal when evaluating review helpfulness, and the results carry important practical implications. In the third essay, I explore effects of the emotions embedded in a seller review on its perceived helpfulness to readers. I propose that over and above the well-known negativity bias, the impact of discrete emotions in a review will vary, and that one source of this variance is perceptions of reviewers' cognitive effort. I focus on the roles of two distinct, negative emotions common to seller reviews: anxiety and anger. In Studies 1 and 2, experimental methods were utilized to identify and explain the differential impact of anxiety and anger in terms of perceived reviewer effort. In Study 3, actual seller reviews from Yahoo! Shopping websites were collected to examine the relationship between emotional review content and helpfulness ratings. These findings demonstrate the importance of discriminating between discrete emotions in online word-of-mouth, and they have important repercussions for consumers and online retailers.

This thesis examines six trans feminine informants in New York City's experiences of oppression, trans-misogyny, femi-negativity, racism, and classism, as well as their experiences of community support, conflicts and resistance practices through the lens of the term sisterhood and the practice of sisterhooding. Focus has also been placed on the informant's views on allyship and coalition, and their relationship to other communities, such as the trans masculine community. The research has been conducted through in-depth, semi-structured, qualitative interviews with six trans feminine activists in New York City. The informant group was heterogenous in regards to age, race/ethnicity, as well as in regards to where in the city they resided and which parts of the movement they were engaged in. My findings follow Jenny Gunnarsson Payne's (2006) theory on sisterhood as an empty signifier, as my informants had different definition's of the term and concept of sisterhood, and while all of them expressed ambivalences towards the term and concept, they also all used the term to varying degrees. Several saw advantages in using the term to describe kinship and solidarity between trans feminine people. The participating informants in the study listed several different conflicts within trans feminine movements. Many of them were generally skeptical to conflicts, especially to those related to cattiness, competition, language and terminology – sentiment's which I agree with, albeit with the addition, which some of my informant's also stressed, that certain conflict's regarding differences in oppressions related to intersectional hierarchies, may be necessary. In the concluding chapter I argue for an understanding of trans-sisterhood based both on an understanding of similarities and difference's in experience and an understanding of solidarity that prioritizes the voices, perspectives and leadership of the most marginalized. My informant's described grave street harassment, employment discrimination and experiences of desexualization from gay/queer men and hypersexualization from so-called tranny chasers. Because of the lack of previous research on trans femininities from the perspective of an understanding of the specific oppressions of trans-misogyny and femi-negativity, this thesis has had a broad, rather then detailed, perspective and following in the foot steps of Julia Serano (2007) argues for an analysis on the position of trans women and other trans femininities beyond the gender neutral category of transgender. A majority of my informants sharp statements on the subordination of trans femininity to trans masculinity supports my argument for the need of more research in the field of trans femininity studies with perspectives from both transgender studies and critical femininity studies. / Genom djupintervjuer undersöker uppsatsen sex olika transfeminina informanter i New Yorks erfarenheter av förtryck, trans-misogyni, femi-negativitet, rasism och klassism, såväl som deras erfarenheter av stöd, konflikter och motståndspraktiker, vilket sker genom ett undersökande av deras inställning till termen systerskap och den systerskapande praktiken. Fokus har också legat på informanternas syn på allierade, koalitioner och deras relation till andra grupper, som till exempel transmaskulina personer. För att fånga in en intersektionell bredd av erfarenheter var informantgruppen heterogen i förhållande till ålder, “ras”/etnicitet, samt i förhållande till var de bodde i staden och vilka delar av rörelsen de var engagerade i. Informanterna beskrev grova erfarenheter av trakasserier på gatorna och diskriminering på arbetsmarknaden, samt erfarenheter av hypersexualisering från så kallade tranny chaser's och avsexualisering från homosexuella och queera män. I linje med Jenny Gunnarsson Payne's (2006) teori om systerskap som tom signifikant, hade mina informanter många olika definitioner av begreppet systerskap, och medan många av dem uttryckte ambivalenser i förhållande till termen, använde sig alla av begreppet i varierande grad. Flera av dem såg stora fördelar i att använda termen för att beskriva samhörighet och solidaritet mellan transfeminina. Mina informanter listade flera olika konflikter inom de transfeminina rörelsen och var allmänt skeptiska till konflikter, framförallt till de som handlade om elaka attityder, tävlande, språk och terminologi – vilket jag håller med dem om, med tillägget, som en del informanter också tydliggjorde, att visa konflikter gällande intersektionella hierarkier kan vara nödvändiga. Jag argumenterar  för en förståelse av trans-systerskap som baseras både i en förståelse av likheter och skillnader i erfarenheter sam i en förståelse av solidaritet som prioriterar perspektiven och ledarskapet av de mest marginaliserade rösterna. Uppsatsen har ett brett perspektiv eftersom det tidigare gjorts väldigt lite forskning om transfemininiter utifrån den specifika förståelsen av trans-misogyni och femi-negativitet. I likhet med Julia Serano (2007) argumenterar jag för ett analyserande av transkvinnors och andra transfemininas situation bortanför trans som könsneutral kategori och får stöd i majoriteten av mina informanters skarpa uttalanden om den hierarkiska underordningen av transfemininitet gentemot transmaskulinitet. Slutligen menar jag att det behövs mer forskning inom fältet transfemininitetsstudier med perspektiv både från kritiska femininitetsstudier och transstudier.

L’amusie congénitale est un trouble neuro-développemental qui s’exprime par un déficit de discrimination tonale fine. Le cerveau des amusiques ne répond pas aux petites différences de hauteur, tel que révélé par l’absence de la composante de potentiel évoqué P3b, qui est associée aux processus de discrimination tonale tardifs et conscients. Peu d’études se sont penchées sur les mécanismes précoces et préconscients de discrimination tonale chez les amusiques, qui peuvent être étudiés par l’entremise d’une composante de potentiel évoqué appelée la négativité de discordance (MMN). Certaines études ont démontré qu’il est possible d’enregistrer la MMN pendant la présentation d’un film avec la trame sonore en simultané aux sons visant à évoquer la composante. Toutefois, une étude a démontré que la présentation de la trame sonore réduisait l’amplitude de la MMN, sans néanmoins clarifier la nature de l’effet d’interférence en cause. Les objectifs du présent projet sont d’abord, d’investiguer les effets à l’origine de la réduction d’amplitude de la MMN observée lors de la présentation d’un film avec la trame sonore, puis d’évaluer cette même composante chez les amusiques. La première étude visait à déterminer si un effet d’interférence attentionnelle ou acoustique était en cause dans la réduction d’amplitude observée sur la MMN lors de la présentation de la trame sonore d’un film. Les résultats ont montré qu’un effet de masquage acoustique, attribuable à la trame sonore, était responsable de la réduction d’amplitude de la MMN, cette dernière augmentant au fur et à mesure que l’intensité sonore de la trame du film était réduite. La seconde étude a été conduite dans le but d’investiguer la MMN chez les amusiques et de vérifier si le complexe d’ondes anormales N2b-P3b, observé en réponse aux grandes différences tonales chez les amusiques, pouvait être attribuable à un effet de saillance des stimuli. Dans un premier temps, nous avons comparé la MMN des amusiques à celle des contrôles, puis nous avons modifié le paradigme expérimental visant à évoquer la N2b-P3b en ajustant les probabilités d’occurrence des sons présentés aux contrôles en fonction des sons perçus par les amusiques. Les résultats ont montré que le cerveau des amusiques parvient à discriminer les différences de hauteur à un niveau précoce et préconscient, tel que révélé par une MMN normale, mais que les réponses cérébrales plus tardives, associées au processus de discrimination des hauteurs conscient, sont anormales chez les amusiques, et ce, uniquement pour les petites différences de hauteur, tel que révélé par l’absence de la P3b. En conclusion, ces résultats démontrent que l’amplitude de la MMN est affectée de manière significative par la présentation de la trame sonore d’un film et que cela est attribuable à un effet d’interférence acoustique. Dans un deuxième temps, nous avons démontré que les mécanismes précoces et préconscients de discrimination tonale sont préservés chez les amusiques, et que le déficit sous-jacent à l’amusie congénitale est attribuable à une atteinte du processus de discrimination tonale fine associé à un niveau de traitement cérébral tardif et conscient, le complexe d’ondes anormales N2b-P3b étant pour sa part attribuable à un effet de saillance des stimuli. / Congenital amusia is a neurodevelopmental disorder which is characterized by a deficit in fine-grained pitch discrimination. In fact, the amusic brain does not respond to small pitch changes, such as reflected by the absence of the event-related (ERP) component P3b, which is associated to late and conscious pitch discrimination processes. Until now, very few studies focused on early preconscious levels of processing in amusia, which can be studied through an ERP component called the mismatch negativity (MMN). Some studies have demonstrated that the MMN can be recorded while playing the soundtrack of a movie in concurrence with the MMN-critical tones. However, one study demonstrated that playing the movie soundtrack reduced MMN amplitude, but did not investigate the origin of this effect. The main goals of this project are, first, to investigate the nature of the effect responsible for the MMN reduction observed when playing a movie soundtrack, and secondly, to evaluate the MMN in congenital amusia. The first study aimed to investigate if an attentionnal or acoustical interference effect could account for the reduction in MMN amplitude observed when playing the movie soundtrack. The results showed that an acoustical masking effect of the movie soundtrack was responsible for the reduction in MMN amplitude. In fact, MMN amplitude increased as the intensity level of the movie soundtrack decreased. The goal of the second study was to investigate the MMN in congenital amusia, but also to explore if the abnormal N2b-P3b complex observed in amusics in a previous study could be accounted for by an effect of salience of the stimuli. Thus, we first compared the MMN results between amusics and controls, and then, we modified the experimental paradigm meant to evoke the N2b-P3b by adjusting the probabilities of occurrence of the sounds presented to the controls as a function of the sounds perceived by their matched amusics. The results showed that the amusic brain can detect all pitch changes at an early and preconscious level of processing, such as demonstrated by a normal MMN in both groups. Furthermore, our results showed that the amusic brain does not respond normally solely to small pitch changes at a later conscious level of processing, such as revealed by the absence of the P3b, thus showing that the abnormal N2b-P3b complex of ERP components observed in a previous study is better explained by a saliency effect of the stimuli and does not represent an electrophysiological anomaly specific to congenital amusia. In conclusion, our results have first shown that MMN amplitude is decreased by presenting a movie soundtrack and this is due to a masking effect at the acoustical level of the soundtrack over the MMN-critical tones. Finally, our second study showed that the early preconscious mechanisms of pitch discrimination are preserved in congenital amusia, and that the pitch deficit underlying congenital amusia is limited to an anomaly in the late and conscious processing of small pitch changes, the abnormal N2b-P3b complex being rather explained by an effect of salience of the stimuli.

Doctorat en philosophie et lettres / info:eu-repo/semantics/nonPublished

Les dysfonctions interpersonnelles sont au cœur du trouble de la personnalité limite (TPL). La recherche passée a examiné différents mécanismes sous-jacents aux dysfonctions interpersonnelles dans la personnalité limite, incluant la dérégulation émotionnelle et l’impulsivité, les déficits dans la reconnaissance des expressions faciales émotionnelles, la mentalisation faible, la confiance et la coopération faibles, les difficultés concernant l’empathie et l’intimité ainsi que l’instabilité affective et interpersonnelle. Ainsi, la présente thèse vise à développer les connaissances sur les mécanismes socio-cognitifs sous-jacents aux dysfonctions interpersonnelles dans la personnalité limite. Dans ce but, cette thèse examine le rôle des évaluations d’autrui dans la personnalité limite. En effet, chacun forme des évaluations plus ou moins positives ou négatives à partir des premières interactions avec une nouvelle personne et ces impressions, tout en évoluant, demeurent fondamentales dans les interactions sociales, incluant dans les relations amoureuses. Ces évaluations peuvent se manifester de deux manières : en effet, il y a maintenant amplement de preuves empiriques suggérant que les évaluations peuvent résulter de processus relativement réfléchis et délibérés (c.-à.-d., évaluations délibérées) ou qu’elles peuvent émerger à partir de processus plus instantanés où il y a aucune ou peu d’intention consciente d’évaluer le stimulus (c.-à.-d., évaluations spontanées). Dans cette thèse, deux études mesurent les traits de la personnalité limite (PL) sur un continuum de sévérité et examinent si ces traits impliquent des évaluations d’autrui plus négatives ou clivées (c.-à.-d., instables et polarisées) aux niveaux spontané et délibéré. L’étude 1 (N = 204) examinait les évaluations d’un personnage de film à deux temps de mesure, c.-à.-d., après un extrait de film positif et après un extrait de film négatif. Les évaluations spontanées étaient mesurées à l’aide d’une tâche d’amorçage évaluatif et les évaluations délibérées étaient mesurées à l’aide d’une mesure auto-rapportée. L’étude 1 examinait deux hypothèses principales : si les traits du PL étaient liés à (1) plus d’instabilité et (2) plus de négativité dans les évaluations du personnage de film aux niveaux délibéré et spontané. Les résultats montraient que les participants évaluaient généralement positivement le personnage sur les deux types d’évaluations. Contrairement à l’hypothèse de l’instabilité, les traits du PL n’impliquaient pas d’alternance entre des évaluations positives et négatives ou entre des évaluations négatives et positives. Cela était vrai pour les évaluations spontanée et délibérée. Toutefois, les deux types d’évaluations impliquaient des biais négatifs contextuels. Spécifiquement, les traits PL étaient reliés à des évaluations relativement plus négatives du personnage de film. Ce patron de résultat est discuté à la lumière des considérations additionnelles suivantes : (1) il émergeait dans différentes conditions de l’étude selon le type d’évaluations, (2) il semblait avant tout déterminé par davantage de positivité chez les individus avec des traits PL faibles et (3) il était basé sur une interaction marginale à trois voies pour la mesure implicite. Pris dans leur ensemble, les résultats obtenus avec les mesures explicite et implicite dans l’étude 1 convergent partiellement avec les appuis empiriques et les théories cliniques sur les biais négatifs dans le TPL, mais il importe de nuancer les résultats sur la mesure implicite considérant qu’ils sont basés sur une interaction marginale. L’étude 2 (N = 292) examinait les évaluations du partenaire après que les participants aient imaginé soit (a) que leur partenaire les rejetait ou (b) qu’il cherchait une connexion (c) ou sans qu’ils aient imaginé aucun scénario (condition contrôle). Les évaluations spontanées du partenaire étaient mesurées avec une tâche de lettre-nom (name-letter task) et les évaluations délibérées du partenaire étaient mesurées à l’aide d’une mesure auto-rapportée. L’étude 2 examinaient deux hypothèses principales : si les traits PL étaient liés (1) à des évaluations plus polarisées du partenaire (c.-à.-d., alternance entre les valences positive et négative) ou (2) à des évaluations plus négatives du partenaire. Ces deux hypothèses étaient examinées au niveau des évaluations spontanées et délibérées. D’abord, conformément à la recherche passée, les résultats montraient que les participants avaient des évaluations à prédominance positives à l’endroit de leur partenaire et d’eux-mêmes. Deuxièmement, contrairement aux hypothèses, les manipulations de rejet et de connexion n’influençaient pas les évaluations spontanées du partenaire et leur influence sur les évaluations délibérées du partenaire était marginale et petite. Troisièmement, les résultats ne supportaient pas l’hypothèse de la polarité : les individus avec des traits PL élevés ne manifestaient pas davantage de positivité après la condition de connexion et ils ne manifestaient pas davantage de négativité après la condition de rejet. Plutôt, les individus avec des traits PL élevés avaient une préférence réduite pour les initiales de leur partenaire et rapportaient des réactions moins positives à l’endroit de leur partenaire indépendamment des conditions de l’étude, conformément à un biais négatif généralisé sur les deux types d’évaluations. La discussion nuance les implications des résultats pour prendre en compte le fait que les conditions expérimentales n’ont pas produit les effets principaux attendus sur les évaluations du partenaire. Prises dans leur ensemble, les deux études ont trouvé des évaluations généralement positives et les traits PL modulaient ces effets : les deux études comportent des preuves préliminaires suggérant que les individus avec des traits PL pourraient évaluer relativement plus négativement les autres et que ces biais négatifs pourraient se présenter au niveau de leurs évaluations spontanées et délibérées. Ces résultats suggèrent que de potentiels biais négatifs à l’endroit d’autrui pourraient être issus d’une combinaison de processus à la fois relativement précoces et tardifs dans les étapes de traitement de l’information. Toutefois, cette interprétation est nuancée et considérée avec prudence étant donné (a) qu’elle est basée en partie sur des effets marginaux, (b) que certains effets n’ont pas été répliqués à travers les conditions de chaque étude et d’une étude à l’autre et (c) que certains des effets principaux attendus des conditions expérimentales n’ont pas été observés dans l’étude 2. / Interpersonal dysfunctions are central to borderline personality disorder (BPD). Past research has examined different mechanisms underlying interpersonal dysfunctions in borderline personality, including emotion dysregulation and impulsivity, deficits in facial emotion recognition, low mentalization, low trust and cooperation, impairments in empathy and intimacy as well as affective and interpersonal instability. The present thesis also aims at obtaining deeper insights into the interplay of socio-cognitive mechanisms underlying interpersonal dysfunctions in borderline personality. Toward this goal, this thesis examined the role of evaluations of others in borderline personality. In fact, evaluations of others exist from the first moment when we meet someone and it remains one of the most fundamental impressions we have in our social interactions, including in romantic interactions. Such evaluations can present at two levels of evaluations; in fact, there is ample evidence that evaluations can be the result of relatively thoughtful, deliberate processes (i.e. deliberate evaluations) or of relatively instantaneous processes where there is no or little conscious intention to evaluate the stimuli (i.e. spontaneous evaluations). In this thesis, two studies assessed borderline personality (BP) features on a continuum of severity and examined whether these features are related with negative or split-off (i.e., unstable and polarized) evaluations of others at the spontaneous and deliberate levels of evaluations. Study 1 (N = 204) examined evaluations of a movie character at two different times, that is, after a positive clip and after a negative clip. Spontaneous evaluations were measured with an evaluative priming task and deliberate evaluations were measured with a self-report measure. Study 1 examined two main hypotheses: whether BP features are related with (1) more unstable or (2) more negative evaluations of the movie character at the spontaneous and deliberate levels of evaluations. Results showed that participants had overall positive evaluations of the movie character on both types of evaluations. Contrary to the instability hypotheses, BP features involved no switch from positive to negative evaluations or from negative to positive evaluations on either type of evaluations. However, we found evidence for context-specific negativity biases for both spontaneous and deliberate evaluations. Specifically, BP features were related with relatively more negative evaluations of the movie character. This effect was interpreted in light of the following additional considerations: (1) it emerged in different conditions of the study depending on the type of evaluations, (2) it appeared to be driven by greater positivity in individuals with low BP features and (3) it relied on a marginal three-way interaction regarding the implicit measure. Together, the results obtained on the explicit and implicit measures in Study 1 partially converge with empirical evidence and clinical theorizing about negativity biases in BPD and the result on the implicit measure should be considered with prudence given that it relies on a marginal three-way interaction. Study 2 (N = 292) examined partner evaluations after participants imagined either (a) that their partner rejected them or (b) sought connection or (c) imagined no scenario (control condition). Spontaneous partner evaluations were measured with a name-letter task and deliberate partner evaluations were measured with a self-report measure. Study 2 examined two main hypotheses: whether BP features are related with (1) more polarized partner evaluations (i.e., alternation between negativity and positivity) or (2) more negative partner evaluations at the spontaneous and deliberate levels of evaluations. First, replicating prior research, results showed that individuals had predominantly positive evaluations of themselves and of their partner. Second, contrary to expectations, the rejection and closeness manipulations did not influence spontaneous partner evaluations and their influence on deliberate partner evaluations was marginal and small. Third, the results did not support the polarity hypothesis: individuals with high BP features did not display greater positivity after the closeness condition and greater negativity after the rejection condition. Instead, individuals with high BP features showed a reduced preference for their partner’s initials and reported less positive reactions to their partner independent of study conditions, in line with a generalized negativity bias on both types of evaluations. The discussion nuances the implications of the results to take in consideration the fact that the experimental conditions did not produce the expected main effects on partner evaluations. Taken together, both studies found overall more positive evaluations, but BP features modulated this effect: we found preliminary evidence that individuals with high BP features had more negative evaluations (i.e., negativity biases) on both kinds of evaluations and in both studies. These results suggest that potential negativity biases toward others may be shaped both at relatively early and late processing stages in borderline personality. However, this interpretation is considered with prudence given that (a) it is partly based on marginal effects, (b) that some effects did not replicate across conditions of each study or across the two studies and (c) that the expected main effects of experimental conditions were not observed in Study 2.

Abstract To be able to acquire, produce, and comprehend language, precise central auditory processing (CAP), neural processes utilized for managing auditory input, is essential. However, the auditory environments are not always optimal for CAP because noise levels in children’s daily environments can be surprisingly high. In young children, CAP and its developmental trajectory as well as the influence of noise on it have scarcely been investigated. Event-related potentials (ERPs) offer promising means to study different stages of CAP in small children. Sound processing, preattentive auditory discrimination, and attention shifting processes can be addressed with obligatory responses, mismatch negativity (MMN), and novelty P3 of ERPs, respectively. In this thesis the developmental trajectory of CAP from 2 to 4 years of age as well as noise-induced changes on it, were investigated. In addition, the feasibility of the multi-feature paradigm with syllable stimuli and novel sounds in children was evaluated. To this end, obligatory responses (P1, N2, and N4) and MMNs for consonant, frequency, intensity, vowel, and vowel duration changes, as well as novelty P3 responses, were recorded in a silent condition and with babble noise using the multi-feature paradigm. The participants were voluntary, typically developing children. Significant P1, N2, N4, and MMN responses were elicited at both ages. Also a significant novelty P3, studied at the age of 2 years, was found. From 2 to 4 years, the P1 and N2 latencies shortened. The amplitudes of N2, N4, and MMNs increased and the increment was the largest at frontal electrode locations. During noise, P1 decreased, N2 increased, and the latency of N4 diminished as well as MMNs degraded. The noise-induced changes were largely similar at both ages. In conclusion, the multi-feature paradigm with five syllable deviant types and novel sounds was found to be an appropriate measure of CAP in toddlers. The changes in ERP morphology from 2 to 4 years of age suggest maturational changes in CAP. Noise degraded sound encoding, representation forming, and auditory discrimination. The children were similarly vulnerable to hampering effects of noise at both ages. Thus, noise might potentially harmfully influence language processing and thereby its acquisition in childhood. / Tiivistelmä Kielen omaksumiselle, tuottamiselle sekä ymmärtämiselle on tärkeää tarkka keskushermostollinen kuulotiedon käsittely eli ne hermostolliset prosessit, joita käytetään kuullun aineksen käsittelyyn. Kuunteluympäristöt eivät kuitenkaan aina ole optimaalisia kuulotiedon käsittelylle, sillä melutasot lasten elinympäristöissä voivat olla hyvinkin korkeita. Pienten lasten kuulotiedon käsittelyä, sen kehittymistä ja melun vaikutusta siihen on tutkittu vähän. Kuuloherätevasteet ovat toimiva tapa tarkastella pienten lasten kuulotiedon käsittelyä eri näkökulmista. Äänen käsittelyä, esitietoista kuuloerottelua ja tarkkaavuuden siirtymistä voidaan tarkastella obligatoristen vasteiden, poikkeavuusnegatiivisuuden ja novelty P3 -vasteiden avulla. Tässä väitöskirjassa tarkastellaan kuulotiedon käsittelyn kehittymistä kahden vuoden iästä neljän vuoden ikään sekä melun vaikutusta siihen. Lisäksi arvioidaan tavuärsykkeitä ja poikkeavia ääniä sisältävän monipiirreparadigman soveltuvuutta lapsitutkimuksiin. Tutkimuksissa rekisteröitiin monipiirreparadigman avulla obligatorisia vasteita (P1, N2 ja N4); konsonantin, taajuuden, intensiteetin, vokaalin ja vokaalin keston muutokselle syntyneitä MMN-vasteita sekä novelty P3 -vasteita hiljaisuudessa ja taustamelussa. Tutkimuksen osallistujat olivat vapaaehtoisia tyypillisesti kehittyviä lapsia. Molemmilla tutkimuskerroilla P1, N2, N4 ja MMN poikkesivat merkitsevästi nollatasosta samoin kuin kaksivuotiailta tutkittu novelty P3. Kahden vuoden iästä neljään vuoteen P1- ja N2-vasteiden latenssi lyheni sekä N2, N4 ja MMN vahvistuivat, muutoksen ollessa suurinta frontaalisilla elektrodeilla. Melun aikana P1 heikkeni, N2 vahvistui ja N4-vasteen latenssi lyhentyi. Lisäksi MMN-vaste heikkeni. Melun aiheuttamat muutokset olivat samankaltaisia sekä kahden että neljän vuoden iässä. Johtopäätöksenä voidaan todeta viittä eri tavuärsyketyyppiä ja yllättäviä ääniä sisältävän monipiirreparadigman olevan toimiva menetelmä taaperoiden kuulotiedon käsittelyn tutkimiseen. Kahden ja neljän ikävuoden välillä tapahtuvat muutokset vasteissa kuvastavat kehityksellisiä muutoksia kuulotiedon käsittelyssä. Melu heikentää äänitiedon peruskäsittelyä, edustumien muodostumista ja esitietoista kuuloerottelua. Lapset olivat lähes yhtä alttiita melun vaikutuksille sekä kahden että neljän vuoden iässä. Melu voi siis haitata kielen prosessointia ja sen omaksumista.

No description available.

<p><b>Purpose:</b> Children with speech sound disorder (SSD) mispronounce more speech sounds than is typical for their age and a growing body of research suggests that a deficit in speech perception abilities contributes to development of the disorder. However, little work has been done to characterize the neurophysiological processes indexing speech perception deficits in SSD. The primary aim of the current study was to compare the neural activity underlying speech perception in young children with SSD and typical development (TD).</p><p><b>Method</b>: Twenty-eight children ages 4;1-6;0 participated in the current study. Event-related potentials (ERPs) were recorded while children completed a speech perception task which included phonetic (speech sound) and lexical (meaning) matches and mismatches. Groups were compared on their judgment accuracy for matches and mismatches as well as the mean amplitude of the Phonological Mapping Negativity (PMN) and N400 ERP components.</p><p><b>Results</b>: Children with SSD demonstrated lower judgment accuracy across the phonetic and lexical conditions compared to peers with TD. The ERPs elicited by lexical matches and mismatches did not distinguish the groups. However, in the phonetic condition, the SSD group exhibited a more consistent left lateralized PMN effect and a delayed N400 effect over frontal sites compared to the TD group.</p><p><b>Conclusions</b>: These findings provide some of the first evidence of a delay in the neurophysiological processing of phonological information for young children with SSD compared to their peers with TD. This delay was not present for the processing of lexical information, indicating a unique difference between children with SSD and TD related to speech perception of phonetic errors.</p>

No description available.