174 research outputs found

    A review on the electroencephalography markers of Stroop executive control processes

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    The present article on executive control addresses the issue of the locus of the Stroop effect by examining neurophysiological components marking conflict monitoring, interference suppression, and conflict resolution. Our goal was to provide an overview of a series of determining neurophysiological findings including neural source reconstruction data on distinct executive control processes and sub-processes involved in the Stroop task. Consistently, a fronto-central N2 component is found to reflect conflict monitoring processes, with its main neural generator being the anterior cingulate cortex (ACC). Then, for cognitive control tasks that involve a linguistic component like the Stroop task, the N2 is followed by a centro-posterior N400 and subsequently a late sustained potential (LSP). The N400 is mainly generated by the ACC and the prefrontal cortex (PFC) and is thought to reflect interference suppression, whereas the LSP plausibly reflects conflict resolution processes. The present overview shows that ERP constitute a reliable methodological tool for tracing with precision the time course of different executive processes and sub-processes involved in experimental tasks involving a cognitive conflict. Future research should shed light on the fine-grained mechanisms of control respectively involved in linguistic and non-linguistic tasks

    Learning to read aligns visual analytical skills with grapheme-phoneme mapping: evidence from illiterates

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    Learning to read puts evolutionary established speech and visual object recognition functions to novel use. As we previously showed, this leads to particular rearrangements and differentiations in these functions, for instance the habitual preference for holistic perceptual organization in visual object recognition and its suppression in perceiving letters. We performed the experiment in which the differentiation between holistic non-letter processing and analytic letter processing in literates was originally shown (van Leeuwen and Lachmann, 2004) with illiterate adults. The original differentiation is absent in illiterates; they uniformly showed analytic perception for both letters and non-letters. The result implies that analytic visual perception is not a secondary development resulting from learning to read but, rather, a primary mode of perceptual organization on a par with holistic perception

    Neurodynamics of executive control processes in bilinguals: evidence from ERP and source reconstruction analyses

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    International audienceThe present study was designed to examine the impact of bilingualism on the neuronal activity in different executive control processes namely conflict monitoring, control implementation (i.e., interference suppression and conflict resolution) and overcoming of inhibition. Twenty-two highly proficient but non-balanced successive French–German bilingual adults and 22 monolingual adults performed a combined Stroop/Negative priming task while event-related potential (ERP) were recorded online. The data revealed that the ERP effects were reduced in bilinguals in comparison to monolinguals but only in the Stroop task and limited to the N400 and the sustained fronto-central negative-going potential time windows. This result suggests that bilingualism may impact the process of control implementation rather than the process of conflict monitoring (N200). Critically, our study revealed a differential time course of the involvement of the anterior cingulate cortex (ACC) and the prefrontal cortex (PFC) in conflict processing. While the ACC showed major activation in the early time windows (N200 and N400) but not in the latest time window (late sustained negative-going potential), the PFC became unilaterally active in the left hemisphere in the N400 and the late sustained negative-going potential time windows. Taken together, the present electroencephalography data lend support to a cascading neurophysiological model of executive control processes, in which ACC and PFC may play a determining role

    An Electrophysiological Examination of Attentional Biases to Emotional Faces in Depression and Social Anxiety

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    Cognitive theories have proposed that major depressive disorder (MDD) and social anxiety disorder (SAD) involve attentional biases toward and away from specific environmental stimuli. Research has often examined these biases in response to emotional facial expressions, but evidence of attentional biases is mixed. An event-related potential called the N2pc offers advantages over other measures of attentional bias and may clarify conflicting findings. Studies on the N2pc and social anxiety have found consistent results, but there is little work examining depression. Previous N2pc studies are limited by the types of emotional faces they use and by comparing attention for emotional faces only with neutral faces. Further, the effect of MDD-SAD comorbidity has not been thoroughly examined using the N2pc. In this study, undergraduate participants completed self-report questionnaires of depression and social anxiety symptoms. Electroencephalography and reaction time (RT) data were collected during a modified dot-probe task that put emotional faces (angry, disgust, sad, and happy) in direct competition with each other and with neutral faces. ANCOVAs predicting the N2pc and RT showed that no depression or social anxiety-related attentional biases were stronger for any one face type relative to biases for the other face types. However, multiple regressions predicting attentional bias toward specific face type showed that depression and social anxiety interacted to predict attentional biases. Depression was associated with an N2pc attentional bias toward sad faces when social anxiety was low. Social anxiety was related to an N2pc attentional bias away from angry faces at low depression and towards angry faces at high depression, and there was an RT attentional bias away from disgust faces at low depression. Additionally, depression was related to an attentional bias away from neutral faces, while social anxiety was related to a bias toward them. These findings bolster evidence of a sad-related bias in depression and social threat-related biases in social anxiety but highlight the generally overlooked impact of co-occurring symptoms. Interventions for MDD and SAD should target attentional biases in a nuanced manner that considers comorbidity and patterns of both vigilance for and avoidance of social stimuli

    Processamento da confiabilidade em caras: o papel das diferenças individuais nos estilos de vinculação

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    Research suggests that the presence of a human face elicits automatic appraisals of its trustworthiness. To completely understand trust-based interactions, research must consider not only the characteristics of the person that make him or her trustworthy but also the observer effects that contribute to individual variation in such judgments. Based on the assumption that different attachment styles can influence attention mechanisms and information processing, the main goal of the current dissertation was to investigate the impact of attachment representations on the processing of facial cues that resemble (un)trustworthiness. Using a multi-method approach, this thesis investigated the novel issue of whether and how attachment styles are related to interpretational (Study 1) and/or attentional biases of facial (un)trustworthiness (Study 2 and 3). In Study 1, using a sample of 179 participants, we asked the simple but fundamental question of whether individuals with different attachment styles differ in their conscious appraisal of facial trustworthiness. Given that recent studies have shown that individuals high in trait anxiety are also biased to interpret ambiguous stimuli in a threatening way, we also explored whether individuals level of (trait and state) anxiety would also impact judgments of trustworthiness. We found that both anxiosuly-attached and highly trait-anxious individuals were more sensitive to changes in untrustworthy than trustworthy faces, judging unfamiliar untrustworthy and neutral-looking faces as more untrustworthy than less anxious individuals. In study 2, using one of the most widely used tasks in attention bias research, we aimed to investigate the extent to which an individual’s attachment style is associated with selective attention to un(trustworthy) faces. Specifically, our second study introduced an adapted dot-probe design to more clearly investigate what specific selective attention processes (orienting or disengaging) is responsible for a potential attentional bias in insecure individuals. With a sample of 167 participants, our findings suggested that both individuals who scored high on anxious-attachment and trait-anxiety have a difficulty disengaging their attention from untrustworthy faces. Finally, in our third study, we employed another widely used electroencephalography paradigm (the oddball task) to examine the neural correlates of facial untrustworthiness processing and shed light on the temporal characteristics of a possible processing bias toward untrustworthy faces. With a sample of 56 participants, our results revealed greater P3 (350-600 ms) amplitude in response to untrustworthy than neutral faces, suggesting that untrustworthy faces are more salient to all individuals. To our knowledge, the present investigation is the first one to assess whether and how attachment styles are associated with the processing of facial cues that resemble (un)trustworthiness.Investigações sugerem que a presença de uma cara humana provoca uma avaliação automática do seu nível de confiabilidade. Para compreender completamente as interações baseadas na confiança, a investigação deve considerar, para além das características do parceiro que o/a tornam confiável, os efeitos do observador que contribuem para a variação individual nesses julgamentos. Tendo como base a ideia de que diferentes tipos de vinculação podem influenciar os mecanismos atencionais e o processamento de informação, a presente tese teve como principal objetivo investigar o impacto do estilo de vinculação no processamento da confiabilidade em caras. Com o recurso a diferentes métodos de investigação, o presente trabalho investigou o tópico inovador de uma potencial correlação entre o tipo de vinculação e a presença de um viés interpretativo (Estudo 1) e/ou atencional (Estudos 2 e 3) em relação a caras que variam na sua confiabilidade. O Estudo 1, com uma amostra de 179 participantes, teve como base a simples, mas pertinente, questão de saber se indivíduos com estilos de vinculação diferentes diferem na sua avaliação consciente da confiabilidade com base na aparência facial. Dado que estudos recentes demonstraram que indivíduos com graus elevados de ansiedade-traço interpretam estímulos ambíguos como ameaçadores, o primeiro estudo também explorou se o grau de ansiedade (traço e estado) impacta avaliações de confiabilidade. Os resultados sugeriram que tanto indivíduos com uma vinculação ansiosa como indivíduos com graus elevados de ansiedade traço são mais sensíveis a mudanças em faces de baixa, comparativamente a alta, confiabilidade, julgando caras que parecem pouco confiáveis e neutras como menos confiáveis, do que indivíduos menos ansiosos. O Estudo 2, recorrendo a uma das tarefas mais usadas na investigação sobre enviesamentos atencionais, teve como objetivo investigar o grau de associação entre o estilo de vinculação e a atenção seletiva para caras que variam em confiabilidade. Especificamente, o segundo estudo introduziu uma adaptação no design da tarefa de dot-probe, com o intuito de investigar de forma mais precisa quais os processos responsáveis por um potencial viés atencional em indivíduos com uma vinculação insegura. Utilizando uma amostra de 167 participantes, os resultados sugeriram que ambos os indivíduos que pontuaram alto no estilo de vinculação insegura e na ansiedade-traço demonstram dificuldade em desviar a sua atenção de caras com baixa confiabilidade percebida. Por fim, no terceiro estudo, aplicamos uma tarefa amplamente usada em estudos eletroencefalográficos (a tarefa de oddball), com o intuito de avaliar os correlatos neuronais do processamento de confiabilidade em caras e identificar as características temporais de um possível enviesamento em relação a faces pouco confiáveis. Recorrendo a uma amostra de 56 participantes, os resultados revelaram uma maior amplitude na P3 em resposta a caras de baixa confiabilidade comparativamente a caras neutras, sugerindo que estas faces parecem ter um elevado grau de saliência para todos os indivíduos. Tanto quanto sabemos, a presente investigação é a primeira a avaliar se e como é que os estilos de vinculação se associam ao processamento de pistas faciais que aparentam baixa ou alta confiabilidade.Programa Doutoral em Psicologi

    The Effect of Prior Knowledge of Color on Behavioral Responses and Event-Related Potentials During Go/No-go Task

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    In daily life, the meaning of color plays an important role in execution and inhibition of a motor response. For example, the symbolism of traffic light can help pedestrians and drivers to control their behavior, with the color green/blue meaning go and red meaning stop. However, we don’t always stop with a red light and sometimes start a movement with it in such a situation as drivers start pressing the brake pedal when a traffic light turns red. In this regard, we investigated how the prior knowledge of traffic light signals impacts reaction times (RTs) and event-related potentials (ERPs) in a Go/No-go task. We set up Blue Go/Red No-go and Red Go/Blue No-go tasks with three different go signal (Go) probabilities (30, 50, and 70%), resulting in six different conditions. The participants were told which color to respond (Blue or Red) just before each condition session but didn’t know the Go probability. Neural responses to Go and No-go signals were recorded at Fz, Cz, and Oz (international 10–20 system). We computed RTs for Go signal and N2 and P3 amplitudes from the ERP data. We found that RT was faster when responding to blue than red light signal and also was slower with lower Go probability. Overall, N2 amplitude was larger in Red Go than Blue Go trial and in Red No-go than Blue No-go trial. Furthermore, P3 amplitude was larger in Red No-go than Blue No-go trial. Our findings of RT and N2 amplitude for Go ERPs could indicate the presence of Stroop-like interference, that is a conflict between prior knowledge about traffic light signals and the meaning of presented signal. Meanwhile, the larger N2 and P3 amplitudes in Red No-go trial as compared to Blue No-go trial may be due to years of experience in stopping an action in response to a red signal and/or attention. This study provides the better understanding of the effect of prior knowledge of color on behavioral responses and its underlying neural mechanisms

    Cognitive aspects of emotional expression processing

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    This thesis investigates the hypothesis that emotions play an influential role in cognition. Interference between facial emotional expression processing and selected tasks is measured using a variety of experimental methods. Prior to the main experimental chapters, the collection and assessment (Chapter 2, Exp. 1) of stimulus materials is described. Experiments 2-11 then concentrate on the likelihood of interference with other types of information from the face. Findings using a Garner design suggest that, although identity processing may be independent of expression variation, expression processing may be influenced by variation in identity (Exps. 2-4). Continued use of this design with sex (Exps. 6-7) and gaze direction (Exps. 9-10) information appears to support the (mutual) independence of these facial dimensions from expression. This is, however, in contrast to studies that indicate the modification of masculinity judgements by expression (Exp. 5), and the interaction of gaze direction and expression when participants rate how interesting they find a face (Exp. 8). Further to this, a search task (Exp. 11) shows that slower responses to an angry (cf. happy) face looking at us, may be due to the presence of an aversive mouth. Experiments 12-15 test for interference in the field of time perception: complex interactions between expression and encoder and decoder sex are indicated. Finally, Experiments 16-17 find that exposure to a sequence in which the majority of faces are angry depresses probability learning, and that prior exposure to varying quantities of angry and happy faces affects our later memory for them. Overall, there is evidence that exposure to emotional expressions may affect other (selected)c ognitive processesd ependingu pon which expressionsa re used and which experimental methods are chosen. It is suggested that future investigations would benefit from techniques that describe the temporal profile of an emotional response

    The Impact of a Single Session of Mindfulness Meditation on the Attentional Blink in Non-Meditators

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    Attentional resources are limited therefore a stimulus can go undetected if it closely follows another target by 200-500ms. This phenomenon is known as the attentional blink. Mindfulness meditation has been shown to be beneficial in target detection and in decreasing the attentional blink. Since there is no standard for the type of meditation or duration of practice that leads to attention benefits, this study compares the two most popular types of meditation in a group of non-meditators: focused attention and open monitoring meditation. This study utilized an attentional blink paradigm to measure if a single session of mindfulness meditation can improve target detection capabilities. The focused attention group decreased their attentional blink, shown in improved T2 detection whereas the open monitoring group did not however this change was not significant. This finding suggests that focused attention meditation can improve participants’ ability to distribute attentional resources effectively to multiple targets, but a longer session and/or more participants will be necessary to have confidence in this conclusion

    Difficulty disengaging attention from appearance words among women with high social anxiety

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    Pathological eating behaviors (PEB) and body dissatisfaction are more prevalent among women with higher social anxiety (HSA) than women with lower social anxiety (LSA). Attentional bias may play a role in these relationships. Attentional bias toward appearance is related to PEB and body dissatisfaction. Further, difficulty disengaging attention from threat is thought to maintain anxiety among HSA individuals. It follows that some HSA women may find scrutiny regarding their appearance threatening and difficulty disengaging attention from appearance cues may play an especially important role in PEB and/or body dissatisfaction among HSA women. The present study tested this theory, hypothesizing that: (1) HSA women would exhibit greater difficulty disengaging attention from appearance words than LSA women, and (2) HSA women with greater difficulty disengaging attention from appearance words would exhibit greater PEB and body dissatisfaction than HSA women with lower difficulty disengaging attention and LSA women. Difficulty disengaging was examined among 52 undergraduate women (HSA = 26, LSA = 26). Although HSA women reported higher scores on measures of PEB and body dissatisfaction than LSA women, HSA women did not exhibit more difficulty disengaging attention and difficulty disengaging did not moderate the relationships between social anxiety and PEB/body dissatisfaction. Follow-up analyses revealed that HSA women were more likely to engage in binge-eating and restricted eating than LSA women, but difficulty disengaging attention was only related to purging behaviors (regardless of social anxiety status). Among women who engaged in PEB, LSA women with higher difficulty disengaging reported the highest number of PEB
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