Attention to the periphery attenuates the EPN and LPP

Current research shows that emotions have an important role in guiding attention and cognitions especially when the emotional stimuli are affective. Load theory proposes that when the perceptual load on attention is sufficiently high, irrelevant emotional stimuli is no longer attended to and thus will not produce a distracting effect. In this study 18 participants performed two discrimination tasks where their attention was manipulated spatially. To investigate the effect of spatial attention on ERP components, emotional pictures in 14 different semantic categories were shown while EEG was recorded. The results indicate that a successful perceptual load was achieved, reflected in the behavioral data that show there was a clear difference in performance between tasks. Further the results indicate that a strong effect was achieved in the mean amplitudes of both EPN and LPP corresponding to the semantic categories of pictures. Critically directing the attention to the periphery while emotionally salient pictures were presented attenuated the mean amplitude of both EPN and LPP

The effects of valenced odors on facial perception

We use our senses to navigate in the world. An important property of olfaction, the sense of smell, is to enable us to approach beneficial things, and to avoid what might be toxic or otherwise harmful in our environment. Other peoples’ behaviors are also paramount for our survival. Thus, we use our vision to decode their internal states from their facial expressions. For many modalities, multiple senses are integrated to enhance sensory percepts. In this thesis, I investigated how valenced odors affect the perception of facial expressions. Specifically, using a multi-method approach, I studied the integration of unpleasant and pleasant odor contexts on odor-congruent and incongruent facial expressions, disgusted, and happy faces. The effects I am interested in are those that valenced odors have on face perception, attention to faces, and the cortical processing of faces. To answer these questions, I used questionnaires, ratings, EEG, and behavioral measures such as reaction times. Across studies, ratings of face valence are affected in the direction of the odor valence (e.g., faces are rated more negatively in the context of an unpleasant odor). Also, overall, the results in my studies indicate that faces are perceived as more arousing in valenced odor contexts; however, these effects occur regardless of facial expression. In study 1, I found that valenced odors and facial expressions are integrated at an earlier time-frame than previously thought. Specifically, I found that the N170 event-related potential component (ERP) to disgusted facial expressions was lower in amplitude in the unpleasant odor condition than in the pleasant odor condition. This effect was not present for happy faces in the N170 component. An unpleasant odor might thus facilitate the processing of threat-related information. In study 2, I found evidence that odors, in general, did not affect the recognition speed of facial expressions that changed from neutral to disgusted or happy over 3 seconds. Also, I found robust evidence against congruency effects in facial expression recognition reaction times (RTs). The results indicated that faces overall were recognized faster in the unpleasant odor condition. Further, these results were not qualified by individual differences in body odor disgust. Thus, unpleasant odors might facilitate the recognition of facial expressions regardless of trait body odor disgust. In study 3, I studied whether valenced odors directed spatial attention toward odor-congruent facial expressions in a “dot-probe” task. I found decisive evidence that odors do not affect attention towards disgusted and happy facial expressions, casting doubt on the dot-probe experiment. However, I found that probes were detected faster as a function of time-on-task in the unpleasant odor condition. I hypothesized that this effect might be due to maintained vigilance in the presence of an unpleasant odor and task fluency effects. In summary, the results indicate that valenced odors affect facial perception. Generally, faces are perceived as more valenced and arousing in odor contexts. Further, an unpleasant odor may decrease RTs; however, this effect seems to be irrespective of the target type. Also, odor face integration may happen earlier than thought; yet, evidence in the literature is mixed, and more research is needed. The methods I have used may increase transparency and robustness of published results, and help accelerate knowledge development in this field of research

Gender moderates valence effects on the late positive potential to emotional distracters

Attention is captured more strongly by emotional pictures than by neutral pictures. This allocation of attention to emotional pictures is commonly indexed by the late positive potential (LPP), an event-related potential (ERP) that is larger for negative and positive pictures than for neutral pictures. However, findings are mixed in regards to valence effects, that is, whether the LPP is larger for negative pictures than for positive pictures (negativity bias) or vice versa (positivity bias). Additionally, previous ERP studies have not explicitly considered a moderating effect of gender. In the present study, positive, negative, and neutral pictures were shown at fixation but were always task-irrelevant. Results showed that LPP amplitudes for the positive and negative distracters were moderated by gender. Men showed a positivity bias on the LPP. Women did not show a clear valence bias on the LPP, but they showed a negativity bias on picture ratings. These gender differences for the LPP did not habituate, as they were obtained even for pictures that were repeated 20 times. Because previous studies with other measures suggest a positivity bias for men and a negativity bias for women, the present findings extend these studies suggesting that attention allocation for emotional pictures of different valence is similarly moderated by gender

Gender moderates valence effects on the late positive potential to emotional distracters

AbstractAttention is captured more strongly by emotional pictures than by neutral pictures. This allocation of attention to emotional pictures is commonly indexed by the late positive potential (LPP). This event-related potential (ERP) is larger for negative and positive pictures than for neutral pictures. However, findings are mixed in regards to valence effects, that is, whether the LPP is larger for negative pictures than for positive pictures (negativity bias) or vice versa (positivity bias). Additionally, previous ERP studies have not explicitly considered a moderating effect of gender. In the present study, positive, negative, and neutral pictures were shown at fixation but were always task-irrelevant. Results showed that LPP amplitudes for the positive and negative distracters were moderated by gender. Men showed a positivity bias on the LPP (i.e., larger amplitudes for positive pictures than for negative pictures). Women did not show a clear valence bias on the LPP, but they showed a negativity bias on picture ratings. These gender differences for the LPP did not habituate, as they were obtained even for pictures that were repeated 20 times. Because previous studies with other measures suggest a positivity bias for men and a negativity bias for women, the present findings extend these studies suggesting that attention allocation for emotional pictures of different valence is similarly moderated by gender

Do Valenced Odors and Trait Body Odor Disgust Affect Evaluation of Emotion in Dynamic Faces?

Disgust is a core emotion evolved to detect and avoid the ingestion of poisonous food as well as the contact with pathogens and other harmful agents. Previous research has shown that multisensory presentation of olfactory and visual information may strengthen the processing of disgust-relevant information. However, it is not known whether these findings extend to dynamic facial stimuli that changes from neutral to emotionally expressive, or if individual differences in trait body odor disgust may influence the processing of disgust-related information. In this preregistered study, we tested whether a classification of dynamic facial expressions as happy or disgusted, and an emotional evaluation of these facial expressions, would be affected by individual differences in body odor disgust sensitivity, and by exposure to a sweat-like, negatively valenced odor (valeric acid), as compared with a soap-like, positively valenced odor (lilac essence) or a no-odor control. Using Bayesian hypothesis testing, we found evidence that odors do not affect recognition of emotion in dynamic faces even when body odor disgust sensitivity was used as moderator. However, an exploratory analysis suggested that an unpleasant odor context may cause faster RTs for faces, independent of their emotional expression. Our results further our understanding of the scope and limits of odor effects on facial perception affect and suggest further studies should focus on reproducibility, specifying experimental circumstances where odor effects on facial expressions may be present versus absent

Background Odors Modulate N170 ERP Component and Perception of Emotional Facial Stimuli

Successful social interaction relies on the accurate decoding of other peoples’ emotional signals, and their contextual integration. However, little is known about how contextual odors may lead to modulation of cortical processing in response to facial expressions. We investigated how unpleasant and pleasant contextual background odors affected emotion perception and cortical event-related potential (ERP) responses to pictures of faces expressing happy, neutral and disgusted facial expressions. Faces were, regardless of expression, rated more positively in the pleasant odor condition and more negatively in the unpleasant odor condition. Faces were overall rated as more emotionally arousing in the presence of an odor, irrespective of its valence. Contextual odors also interacted with facial expressions, such that happy faces were rated as especially non-arousing in the unpleasant odor condition. The early, face-sensitive N170 ERP component also displayed an interaction effect. Here, disgusted faces were affected by the odor context such that the N170 revealed a relatively larger negativity in the context of a pleasant odor compared with an unpleasant odor. There were no odor effects on the responses to faces in other measured ERP components (P1, VPP, P2, and LPP). These results suggest that odors bias socioemotional perception early stages of the visual processing stream. However, effects may vary across emotional expressions and measurements

Data_Sheet_1_Background Odors Modulate N170 ERP Component and Perception of Emotional Facial Stimuli.DOCX

<p>Successful social interaction relies on the accurate decoding of other peoples’ emotional signals, and their contextual integration. However, little is known about how contextual odors may lead to modulation of cortical processing in response to facial expressions. We investigated how unpleasant and pleasant contextual background odors affected emotion perception and cortical event-related potential (ERP) responses to pictures of faces expressing happy, neutral and disgusted facial expressions. Faces were, regardless of expression, rated more positively in the pleasant odor condition and more negatively in the unpleasant odor condition. Faces were overall rated as more emotionally arousing in the presence of an odor, irrespective of its valence. Contextual odors also interacted with facial expressions, such that happy faces were rated as especially non-arousing in the unpleasant odor condition. The early, face-sensitive N170 ERP component also displayed an interaction effect. Here, disgusted faces were affected by the odor context such that the N170 revealed a relatively larger negativity in the context of a pleasant odor compared with an unpleasant odor. There were no odor effects on the responses to faces in other measured ERP components (P1, VPP, P2, and LPP). These results suggest that odors bias socioemotional perception early stages of the visual processing stream. However, effects may vary across emotional expressions and measurements.</p