Selective attention is a mechanism used to allocate resources to information processing. Both mood states and emotionally salient stimuli can influence which information is selectively attended. This information is subsequently processed in a more elaborative manner and affects task performance. The experiments presented in this thesis explore the influence of mood and emotional stimuli on selective attention and consequently task performance. Mood induction procedures were used to induce transient neutral, sad, and happy mood states in healthy volunteers. A systematic review and meta-analysis of 41 studies using sad mood induction procedures showed cognitive impairments in performance in the context of task neutral stimuli. In contrast biases in attention towards mood-congruent negative stimuli led to improved task performance. A series of three behavioural experiments with 197 participants demonstrated that participants made decisions on the basis of less information when that information was preceded by emotional but not neutral stimuli. Induced mood state did not affect performance. The behavioural and neural correlates of visual attentional processing to emotional stimuli were explored using magnetoencephalography in 24 healthy participants following sad, happy, and neutral mood induction procedures. The M300, a component associated with selective attention, had greater amplitude following presentation of negative compared with positive stimuli, which was associated with improved task performance. Reduced M300 amplitude and impairments in performance occurred following sad mood induction procedures. The experiments presented in this thesis demonstrate prioritized processing of emotional information and provide some evidence for impaired performance following sad mood induction procedures.

Learning of a positive diagnosis of HIV may be one of the most challenging and stressful events in life. The memory of this event is emotionally laden, and even years later evokes an emotional response. Similarly, many people living with HIV (PLH) have memories of the first time they were treated differently because of their diagnosis. While research frequently examines the subjective of stress, few studies have examined biological markers of stress in people living with HIV. Heart Rate Variability offers a non-invasive measure of stress. Beyond serving as a biological marker for stress, changes in HRV are also associated with emotional functioning. Research demonstrates decreased HRV levels in patients with Depression, Anxiety, and PTSD. We conducted a repeated measures MANOVA to examine effects of stress induction on HRV in individuals with high and low levels of HIV-related stigma. We found that the high stigma group was significantly different from the low stigma group in regard to changes in participants’ HRV, Wilks’ λ = .50, F (1, 51) = 11.63, p < .001. A hierarchical linear regression examined the relationship between HRV and other measures of stress (Heart Rate and Blood Pressure). We found that systolic blood pressure and heart rate in the stress condition were predictive of HRV (adjusted R2=.29, F (5,46) =4.07, p<.01). Results of our study support the use of HRV as a measure of stress in HIV-positive adults. Additionally, the results of our study demonstrate significant relationships between stigma, social support and stress in HIV-positive adults.

The current study examined the relationship between affect changes or lack thereof when one logs onto Facebook or Yahoo!. Facebook was specifically chosen for examination in the current study due to its widespread use, its vast effect on society, and its unique features that allow users to obtain information and have social interaction at the same time. Yahoo! served as a control due to the fact that it is a highly popular site that has similar features of Facebook without having the social functions. Both sites allow users to observe news that is pertinent and of interest to them and both are popular; the main difference between the two sites is the social component that Facebook can offer that Yahoo! is unable to offer users. Findings suggest that logging onto Facebook increases positive affect and joy, but this is short lived. After a period of time on the website negative affect and anger increase. Further research needs to be conducted in order to understand what activities on Facebook lead to more or less affect modulation and future studies are discussed.

[pt] A Realidade Virtual tem seu uso sendo disseminado em diversas áreas de conhecimento, incluindo o campo da Psicologia. Assim, vem sendo utilizada como método terapêutico e também em pesquisas científicas. Um desses usos no campo experimental se dá em Procedimentos de Indução de Humor, nos quais o indivíduo é inserido no ambiente virtual por meio de um equipamento eletrônico como mediador. Essa dissertação apresenta dois artigos vinculados a essa temática. O primeiro se trata de uma revisão sistemática realizada para explorar a forma em que a Realidade Virtual é utilizada em indução de humor. Nesta revisão encontramos evidências da eficácia da técnica, além de identificarmos o equipamento de Óculos de Realidade Virtual como o mais utilizado, a população universitária como amostra mais comum e a atividade eletrodérmica como medida fisiológica mais frequentemente utilizada para avaliação da indução. O segundo artigo apresenta um estudo empírico com a intenção de investigar a Realidade Virtual na indução de humor e melhora na capacidade interoceptiva. As análises indicaram efeito de interação entre tempo e grupo para atividade eletrodérmica. Tamanhos de efeito moderados a grandes foram observados para maior reatividade emocional negativa e melhor interocepção, sugerindo que com uma amostra maior esses efeitos poderiam ser significativos. Os resultados de frequência cardíaca não apresentaram diferenças significativas. Os resultados apresentados da atividade eletrodérmica indicam sucesso na indução de emoção. O presente estudo se mostra relevante por trazer novos procedimentos e tecnologias para auxiliar nas pesquisas em psicologia, com a Realidade Virtual se mostrando eficaz em estudos de difícil aplicação. O caráter clínico do estudo é reforçado por sua a intenção em melhorar a capacidade cognitiva da interocepção, apresentando indícios da possibilidade de seu uso em tratamentos clínicos, ajudando o indivíduo em eventos com conteúdo emocional, onde a capacidade de identificar e discernir suas emoções e sensações corporais possibilitaria gerar respostas mais adaptativas. / [en] Virtual Reality has been disseminated in several areas of knowledge, including the field of Psychology, for example being used as a therapeutic method and in scientific research. One of these uses as an experimental tool is as a Mood Induction Procedure, in which the individual experiences a virtual environment mediated through electronic equipment. This dissertation presents two articles related to this theme. The first is a systematic review carried out to explore ways in which Virtual Reality can be used as a mood induction procedure. In this review we found evidence for the efficacy of the method, in addition to identifying the Headmounted Display equipment as the most used, college students as the most common sample and electrodermal activity as the most frequently used physiological measure. The second article presents an empirical study investigating Virtual Reality as a mood inductor and how it can be used to promote emotional reactivity and improve interoception. The analyses indicated significant increases for electrodermal activity in an emotional condition elicited by Virtual Reality. Moderate to large effect sizes were observed for negative emotional reactivity and for interoception, which could be significant with a larger sample. Heart rate results did not show significant differences. The presented results of the electrodermal activity indicate successful mood induction. This study is relevant for presenting new procedures and technologies to assist in research in psychology, with Virtual Reality being a potential experimental tool. The clinical character of the study is reinforced by the promising results of the pilot study in relation to interoception, suggesting that Virtual Reality may be employed in clinical treatments, helping subjects to identify and discern their emotions and sensations in emotional situations, which would allow the development of more adaptive responses.

[pt] A presente dissertação tem como objetivo explorar a conexão entre memórias autobiográficas (MA) e imagética mental (IM) através de uma revisão sistemática e um estudo empírico. A presente revisão investiga o papel da AM e MI como procedimentos de indução de humor (PIH). Os resultados em geral sugerem que uma variedade de pistas tem sido usada para evocar MA ou IM. Verificou-se também que poucos estudos relataram resultados estatísticos sobre a eficácia dos métodos, controle dos efeitos de demanda ou empregaram medidas fisiológicas da emoção. Recomenda-se um trabalho adicional para investigar as implicações dessas questões metodológicas. O estudo empírico explorou os efeitos das tarefas IM (positivo ou neutro) sobre a MA de adultos jovens saudáveis. Na Sessão 1, os participantes se lembraram de um evento triste. Dependendo do grupo, eles deveriam imaginar um cenário alternativo positivo ou neutro para a memória. Duas semanas mais tarde, na Sessão 2, eles tiveram que completar a mesma tarefa de memória. Os resultados indicam que os PIHs foram eficazes, com aumentos no humor negativo após a MA triste e melhorias no humor em ambos os grupos após IM, independentemente do seu conteúdo emocional. Isso sugere que as IMs podem ser usadas como uma estratégia eficaz de regulação emocional para o material autobiográfico negativo, e que o conteúdo emocional das imagens pode não ter um impacto crucial nesse processo, porém são necessários mais estudos para realizar esta avaliação, explorar diferentes tipos de memória emocional e estender esse paradigma para populações clínicas. / [en] The current dissertation aims to explore the connection between autobiographical memories (AM) and mental imagery (MI) through a systematic review and an empirical study. The present review investigates the role of AM and MI as mood induction procedures (MIP). Results broadly suggest that a variety of cues to elicit AM or MI has been used. It was also found that few studies reported statistical results about the methods efficacy, control for demand effects, or employed physiological measures of emotion. Further work investigating the implications of these methodological issues is recommended. The empirical study explored the effects of MI tasks (positive or neutral) on AM of healthy young adults. In Session 1, participants remembered a sad life event. Depending on their group, they should imagine either a positive or a neutral alternative scenario to the memory. Two weeks later, in Session 2, they had to complete the same memory task. Results indicate that MIPs were effective, with increases in negative mood after the sad AM and improvements in mood in both groups after imagery regardless of its emotional content. Memory report revealed that groups had a similar profile of memory intrusion. This suggests that mental imagery may be used as an effective emotional regulation strategy for negative autobiographical material, and that the emotional content of imagery may not have a crucial impact in this process. Further studies are needed to evaluate the use of imagery as emotional regulation, explore different types of emotional memory and extend this paradigm to clinical populations.