210 research outputs found

    Valence, Arousal, and Gender Effect on Olfactory Cortical Network Connectivity: a study using Dynamic Causal Modeling for EEG

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    The cortical network including the piriform (PC), orbitofrontal (OFC), and entorhinal (EC) cortices allows the complex processing of behavioral, cognitive, and context-related odor information and represents an access gate to the subcortical limbic regions. Among the several factors that influence odor processing, their hedonic content and gender differences play a relevant role. Here, we investigated how these factors influence EEG effective connectivity among the mentioned brain regions during emotional olfactory stimuli. To this aim, we acquired EEG data from twenty-one healthy volunteers, during a passive odor task of odorants with different valence. We used Dynamic Causal Modeling (DCM) for EEG and Parametric Empirical Bayes (PEB) to investigate the modulatory effects of odors’ valence on the connectivity strengths of the PC-EC-OFC network. Moreover, we controlled for the influence of arousal and gender on such modulatory effects. Our results highlighted the relevant role of the forward and backward PC-EC connections in odor’s brain processing. On the one hand, the EC-to-PC connection was inhibited by both pleasant and unpleasant odors, but not by the neutral one. On the other hand, the PC-to-EC forward connection was found to be modulated (posterior probability (Pp)>0.95) by the arousal level associated with an unpleasant odor. Finally, the whole network dynamics showed several significant gender-related differences (Pp>0.95) suggesting a better ability in odor discrimination for the female gender

    Human Olfactory Perception: A Literature Review

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    There has been wide debate about the degree to which humans are impacted by olfaction. Despite former assumptions that we are dominantly visual/auditory creatures, recent studies suggest that humans are more highly macrosmatic than originally thought. Humans have demonstrated behavioral, physiological, cognitive and affective responses to olfactory stimuli even when the stimuli were perceived unconsciously. The mechanism by which humans perceive these signals is unclear; there is much debate as to whether the vomeronasal organ is functional in humans. Regardless of the mechanism of perception, it is clear olfaction is psychologically impactful for humans. The following literature review summarizes research in the field related to olfactory functioning and perception. The review discusses animals and their interactions with and use of olfactory cues, the human olfactory system, parallels among animals and humans in reactions to odorants, human sensitivity to odorants, and the vomeronasal organ debate. Human research areas included in the review: human-odorant interaction, odor as an identification marker for individual humans, human psychological response to odors, the impact of odor on human affect and sexual behavior, odor production and preference linked to human characteristics, and the effect of odor on human learning

    Methods to assess food-evoked emotion across cultures

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    Autonomous Assessment of Videogame Difficulty Using Physiological Signals

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    Given the well-explored relation between challenge and involvement in a task, (e.g., as described in Csikszentmihalyi’s theory of flow), it could be argued that the presence of challenge in videogames is a core element that shapes player experiences and should, therefore, be matched to the player’s skills and attitude towards the game. However, handling videogame difficulty, is a challenging problem in game design, as too easy a task can lead to boredom and too hard can lead to frustration. Thus, by exploring the relationship between difficulty and emotion, the current work intends to propose an artificial intelligence model that autonomously predicts difficulty according to the set of emotions elicited in the player. To test the validity of this approach, we developed a simple puzzle-based Virtual Reality (VR) videogame, based on the Trail Making Test (TMT), and whose objective was to elicit different emotions according to three levels of difficulty. A study was carried out in which physiological responses as well as player self- reports were collected during gameplay. Statistical analysis of the self-reports showed that different levels of experience with either VR or videogames didn’t have a measurable impact on how players performed during the three levels. Additionally, the self-assessed emotional ratings indicated that playing the game at different difficulty levels gave rise to different emotional states. Next, classification using a Support Vector Machine (SVM) was performed to verify if it was possible to detect difficulty considering the physiological responses associated with the elicited emotions. Results report an overall F1-score of 68% in detecting the three levels of difficulty, which verifies the effectiveness of the adopted methodology and encourages further research with a larger dataset.Dada a relação bem explorada entre desafio e envolvimento numa tarefa (p. ex., con- forme descrito na teoria do fluxo de Csikszentmihalyi), pode-se argumentar que a pre- sença de desafio em videojogos é um elemento central que molda a experiência do jogador e deve, portanto, ser compatível com as habilidades e a atitude que jogador exibe perante o jogo. No entanto, saber como lidar com a dificuldade de um videojogo é um problema desafiante no design de jogos, pois uma tarefa muito fácil pode gerar tédio e muito di- fícil pode levar à frustração. Assim, ao explorar a relação entre dificuldade e emoção, o presente trabalho pretende propor um modelo de inteligência artificial que preveja de forma autônoma a dificuldade de acordo com o conjunto de emoções elicitadas no jogador. Para testar a validade desta abordagem, desenvolveu-se um jogo de puzzle em Realidade Virtual (RV), baseado no Trail Making Test (TMT), e cujo objetivo era elicitar diferentes emoções tendo em conta três níveis de dificuldade. Foi realizado um estudo no qual se recolheram as respostas fisiológicas, juntamente com os autorrelatos dos jogado- res, durante o jogo. A análise estatística dos autorelatos mostrou que diferentes níveis de experiência com RV ou videojogos não tiveram um impacto mensurável no desempenho dos jogadores durante os três níveis. Além disso, as respostas emocionais auto-avaliadas indicaram que jogar o jogo em diferentes níveis de dificuldade deu origem a diferentes estados emocionais. Em seguida, foi realizada a classificação por intermédio de uma Má- quina de Vetores de Suporte (SVM) para verificar se era possível detectar dificuldade, considerando as respostas fisiológicas associadas às emoções elicitadas. Os resultados re- latam um F1-score geral de 68% na detecção dos três níveis de dificuldade, o que verifica a eficácia da metodologia adotada e incentiva novas pesquisas com um conjunto de dados maior

    Contribution of perceptual and emotional skills to moral decision-making

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    Moral decision-making is the ability to choose an optimal course of action based on a system of norms and values that guides our behaviour in a community. Even though the models of moral decision-making have mainly focused on cognitive reasoning and emotions, moral decisions - like all kind of decisions - are taken within a context and in interaction with environmental factors. Therefore, the role played by such factors is critical in order to explain how a decision is reached. In Chapter 1, after a systematic overview of the different theoretical models proposed to explain morality, I discuss the evidence in favour of the role played by sensory stimuli in moral choices, focusing on a recent meta-analysis (Landy & Goodwin, 2015a) that showed that besides vision, chemosensory stimuli play a central role in the moral decision process. Then, I explore the link between odours and morality, starting from the disgust emotion, arguing that olfactory stimuli could extend their effects to morality via mechanisms unrelated to disgust, as suggested by the shared neural underpinnings underlying olfaction and moral choices..

    Beyond liking : emotional and physiological responses to food stimuli

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    Background and aim Traditional liking ratings are typically seen as an important determinant in eating behavior. However, in order to better understand eating behavior, we need to first better understand (the dynamic and implicit features underlying) liking appraisal. The aim of this thesis was to investigate the effects of food stimuli varying in sensory modality (smell and taste), pleasantness and intensity, on emotional and physiological responses leading up to liking appraisal. Methods Four studies, using healthy participants, were conducted as part of this thesis. In the first study, responses to pleasant versus unpleasant food odors varying in intensity were measured discretely using pleasantness ratings, intensity ratings and non-verbally reported emotions (PrEmo), as well as continuously using facial expressions and autonomic nervous system (ANS) responses. To further explore how explicit and implicit factors contribute to pleasantness appraisal, the same measures were assessed in response to food odors with a wider range of valence. Next, we focused on facial expressions and ANS responses elicited by single sips of breakfast drinks that were equally liked. In the last study, we investigated changes in pleasantness after consuming semi-liquid meals to (sensory-specific) satiety, combined with measures of facial expressions and ANS responses. Results Both non-verbal reported emotions and emotional facial expressions were demonstrated to be able to discriminate between food odors differing in pleasantness and between food odors differing in intensity. In addition to discrete emotional responses, odor valence associated best with facial expressions after 1 second of odor exposure. Furthermore, facial expressions and ANS responses measured continuously were found odor-specific in different rates over time. Results of food odors with a wider range of valence showed that non-verbally reported emotions, facial expressions and ANS responses correlated with each other best in different time windows after odor presentation: facial expressions and ANS responses correlated best with the explicit emotions of the arousal dimension in the 2nd second of odor presentation, whereas later ANS responses correlated best with the explicit emotions of the valence dimension in the 4th second. For food stimuli varying in flavor (breakfast drinks), facial expressions and ANS responses showed strongest associations with liking after 1 second of tasting, as well as with intensity after 2 seconds of tasting. Lastly, we were able to demonstrate that ANS responses, as well as facial expressions of anger and disgust were associated with satiety. Further effects of sensory-specific satiety were also reflected by skin conductance, skin temperature, as well as facial expressions of sadness and anger. Conclusions Both non-verbal reported emotions and emotional facial expressions were demonstrated to be able to discriminate between food odors differing in pleasantness and/or intensity. Explicit and implicit emotional responses, as well as physiological patterns are related to liking appraisals involved in smelling foods. Implicit measures such as facial expressions and ANS responses can provide more multidimensional information for both food odors and tastes than explicit measures and prove to be highly dynamic over time with specific time courses. Early implicit facial and ANS responses primarily reflect emotion arousal, whereas later ANS responses reflect emotion valence, suggesting dynamic unfolding of different appraisals of food stimuli. Furthermore, ANS responses and facial expressions can reflect pleasantness, satiety, and a combination of both: sensory-specific satiety. This suggests that implicit processes play an important role in dynamic liking appraisals with respect to eating behavior.</p

    Recognizing emotions induced by wearable haptic vibration using noninvasive electroencephalogram

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    The integration of haptic technology into affective computing has led to a new field known as affective haptics. Nonetheless, the mechanism underlying the interaction between haptics and emotions remains unclear. In this paper, we proposed a novel haptic pattern with adaptive vibration intensity and rhythm according to the volume, and applied it into the emotional experiment paradigm. To verify its superiority, the proposed haptic pattern was compared with an existing haptic pattern by combining them with conventional visual–auditory stimuli to induce emotions (joy, sadness, fear, and neutral), and the subjects’ EEG signals were collected simultaneously. The features of power spectral density (PSD), differential entropy (DE), differential asymmetry (DASM), and differential caudality (DCAU) were extracted, and the support vector machine (SVM) was utilized to recognize four target emotions. The results demonstrated that haptic stimuli enhanced the activity of the lateral temporal and prefrontal areas of the emotion-related brain regions. Moreover, the classification accuracy of the existing constant haptic pattern and the proposed adaptive haptic pattern increased by 7.71 and 8.60%, respectively. These findings indicate that flexible and varied haptic patterns can enhance immersion and fully stimulate target emotions, which are of great importance for wearable haptic interfaces and emotion communication through haptics
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