Guillermo Recio

Electrophysiological correlates of perceiving and evaluating static and dynamic facial emotional expressions

Recent evidence suggests that dynamic facial expressions of emotion unfolding over time are better recognized than static images. However, the mechanisms underlying this facilitation are unclear. Here, participants performed expression categorizations for faces displaying happy, angry, or neutral emotions either in a static image or dynamically evolving within 150 ms. Performance replicated facilitation of emotion evaluation for happy expressions in dynamic over static displays. An initial emotion effect in event-related brain potentials evidenced in the early posterior negativity (EPN) was both enhanced and prolonged when participants evaluated dynamic in comparison to static facial expressions. Following the common interpretation of the EPN, this finding suggests that the facilitation for dynamic expressions is related to enhanced activation in visual areas starting as early as 200 ms after stimulus onset, presumably due to shifts of visual attention. Enhancement due to dynamic display was also found for the late positive complex (LPC), indicating a more elaborative processing of emotional expressions under this condition at subsequent stages.

The Time Course of Emotion Effects in First and Second Language Processing: A Cross Cultural ERP Study with German–Spanish Bilinguals

To investigate whether second language processing is characterized by the same sensitivity to the emotional content of language – as compared to native language processing – we conducted an EEG study manipulating word emotional valence in a visual lexical decision task. Two groups of late bilinguals – native speakers of German and Spanish with sufficient proficiency in their respective second language – performed each a German and a Spanish version of the task containing identical semantic material: translations of words in the two languages. In contrast to theoretical proposals assuming attenuated emotionality of second language processing, a highly similar pattern of results was obtained across L1 and L2 processing: event related potential waves generally reflected an early posterior negativity plus a late positive complex for words with positive or negative valence compared to neutral words regardless of the respective test language and its L1 or L2 status. These results suggest that the coupling between cognition and emotion does not qualitatively differ between L1 and L2 although latencies of respective effects differed about 50–100 ms. Only Spanish native speakers currently living in the L2 country showed no effects for negative as compared to neutral words presented in L2 – potentially reflecting a predominant positivity bias in second language processing when currently being exposed to a new culture.

Facial EMG responses to emotional expressions are related to emotion perception ability.

Although most people can identify facial expressions of emotions well, they still differ in this ability. According to embodied simulation theories understanding emotions of others is fostered by involuntarily mimicking the perceived expressions, causing a “reactivation” of the corresponding mental state. Some studies suggest automatic facial mimicry during expression viewing; however, findings on the relationship between mimicry and emotion perception abilities are equivocal. The present study investigated individual differences in emotion perception and its relationship to facial muscle responses - recorded with electromyogram (EMG) - in response to emotional facial expressions. N° = °269 participants completed multiple tasks measuring face and emotion perception. EMG recordings were taken from a subsample (N° = °110) in an independent emotion classification task of short videos displaying six emotions. Confirmatory factor analyses of the m. corrugator supercilii in response to angry, happy, sad, and neutral expressions showed that individual differences in corrugator activity can be separated into a general response to all faces and an emotion-related response. Structural equation modeling revealed a substantial relationship between the emotion-related response and emotion perception ability, providing evidence for the role of facial muscle activation in emotion perception from an individual differences perspective.

On pleasure and thrill: The interplay between arousal and valence during visual word recognition

We investigated the interplay between arousal and valence in the early processing of affective words. Event-related potentials (ERPs) were recorded while participants read words organized in an orthogonal design with the factors valence (positive, negative, neutral) and arousal (low, medium, high) in a lexical decision task. We observed faster reaction times for words of positive valence and for those of high arousal. Data from ERPs showed increased early posterior negativity (EPN) suggesting improved visual processing of these conditions. Valence effects appeared for medium and low arousal and were absent for high arousal. Arousal effects were obtained for neutral and negative words but were absent for positive words. These results suggest independent contributions of arousal and valence at early attentional stages of processing. Arousal effects preceded valence effects in the ERP data suggesting that arousal serves as an early alert system preparing a subsequent evaluation in terms of valence.

Recognizing dynamic facial expressions of emotion: Specificity and intensity effects in event-related brain potentials

Emotional facial expressions usually arise dynamically from a neutral expression. Yet, most previous research focused on static images. The present study investigated basic aspects of processing dynamic facial expressions. In two experiments, we presented short videos of facial expressions of six basic emotions and non-emotional facial movements emerging at variable and fixed rise times, attaining different intensity levels. In event-related brain potentials (ERP), effects of emotion but also for non-emotional movements appeared as early posterior negativity (EPN) between 200 and 350ms, suggesting an overall facilitation of early visual encoding for all facial movements. These EPN effects were emotion-unspecific. In contrast, relative to happiness and neutral expressions, negative emotional expressions elicited larger late positive ERP components (LPCs), indicating a more elaborate processing. Both EPN and LPC amplitudes increased with expression intensity. Effects of emotion and intensity were additive, indicating that intensity (understood as the degree of motion) increases the impact of emotional expressions but not its quality. These processes can be driven by all basic emotions, and there is little emotion-specificity even when statistical power is considerable (N (Experiment 2)=102).

Classification of dynamic facial expressions of emotion presented briefly

A number of studies have shown an impact of speed of a developing facial expression of emotion on its recognition and perceived naturalness. Still, the impact of speed at constant, short presentation times, as normally used in many experiments is unclear. In the present study participants classified faces displaying facial expressions of six basic emotions in static and dynamic presentation modes and three different types of neutral movements. Stimuli were created with computer software that allows fine-grained control over action units and dynamic features. Rise times in dynamic expressions varied between 200 and 900 ms. Results replicated classical findings showing better performance for expressions of happiness, and frequent confusions among morphologically similar expressions, and a general dynamic facilitation for most expressions. Importantly, dynamic presentation as such facilitated a more accurate classification, but variations in speed at the fast range studied here had no noticeable effect for expressions of anger, fear, happiness, and surprise. The main exception was sadness, which was best recognised at slow speed and in static pictures, and disgust, which was most unambiguously categorised at fast to moderate speed.

Neurocognitive mechanisms of individual differences in face cognition: A replication and extension

Face cognition performance is related to individual differences in cognitive subprocesses, as reflected in the amplitudes and latencies of event-related brain potentials (ERPs; Herzmann, Kunina, Sommer, & Wilhelm, 2010). In order to replicate and extend these findings, 110 participants were tested on a comprehensive task battery measuring face cognition abilities and established cognitive abilities, followed by ERP recordings in a face-learning-and-recognition task. We replicated the links of the ERP components indicating the speed of structural face encoding (N170 latency) and access to structural representations in memory (early repetition effect [ERE]/N250r) with the accuracy and speed of face cognition and with established cognitive abilities. As a novel result, we differentiated between the accuracy of face perception and face memory on the behavioral and electrophysiological levels and report a relationship between basic visual processes (P100 amplitude) and face memory. Moreover, the brain–behavior relationships for the ERE/N250r held true, even though we eliminated pictorial and perceptual structural codes from the priming effects by using backward masking of the primes with novel unfamiliar faces. On a methodological level, we demonstrated the utility of the latent difference score modeling technique to parameterize ERP difference components (e.g., ERE/N250r) on a latent level and link them to face cognition abilities.

Is personality modulated by language

We administered German and Spanish versions of the Neuroticism Extraversion Openness–Five-Factor Inventory personality inventory to two groups of late bilinguals (second-language learners) of these two languages. Regardless of individuals’ first language, both groups scored higher on Extraversion and Neuroticism when Spanish was the test language. In turn, scores on Agreeability were higher when German was used as the test language. The results are interpreted as evidence for cultural frame shifts consistent with cultural norms associated with the presently used language. Beyond the acquisition of linguistic skills, learning a second language seems to provide individuals with a new range of perceiving and displaying their own personality.

Effects of inter-stimulus interval on skin conductance responses and event-related potentials in a Go/NoGo task

Skin conductance responses (SCRs) to NoGo stimuli have been found to be smaller than to Go stimuli, possibly due to their diminished task relevance. These findings have been obtained at inter-stimulus intervals (ISI) that were unusually short for SCR recordings. Therefore, we tested whether the same findings would also hold at longer ISIs. Simultaneously, effects of ISI duration on the NoGo-N2 and-P3 components of event-related brain potentials (ERPs) were assessed. Go and NoGo stimuli were equiprobable while ISI varied between 2, 5, and 8s. Although increasing the ISI-enhanced SCR amplitudes in general, it did not modulate the attenuation of the response to NoGo relative to Go stimuli. When considered as difference between NoGo and Go conditions, neither the NoGo-N2 nor the NoGo-P3 was affected by ISI variation. Together, these data confirm the feasibility of co-registering ERPs and SCRs.

Time Pressure Inhibits Dynamic Advantage in the Classification of Facial Expressions of Emotion

Recent studies suggest an advantage in the recognition of dynamic over static facial expressions of emotion. Here, we explored the differences in the processing of static and dynamic faces under condition of time pressure. A group of 18 participants classified static and dynamic facial expressions (angry, happy, and neutral). In order to increase the goal-directed attention, instructions emphasized speed and announced time pressure in the interval for the response (maximal 600 ms). Participants responded faster and more accurately in the static than in the dynamic condition. Event-related potentials (ERPs) showed larger amplitude of the P1 (90–130 ms) and LPC (300–600 ms) components for dynamic relative to static stimuli, indicating enhanced early visual processing and emotional attention. On the other hand, the N170 was more negative in static relative to dynamic faces, suggesting better structural encoding for static faces under time pressure. The present study shows some advantages in the processing of static over dynamic facial expressions of emotion when the top-down (goal-driven) attention is strengthened.