Startle reflex modulation by affective face “Emoji” pictographs

The linkage between decision-making and bodily states: an investigation using an emotional startle reflex paradigm and the Iowa Gambling task

Theories such as the somatic marker hypothesis posit that emotions and feedback from bodily states support higher cognition and decision-making. This study investigated the connection between decision-making and activity of the startle reflex, a defense reflex that is sensitive to emotional states. Decision-making was assessed using the Iowa Gambling Task (IGT), which simulates real-life decision-making with respect to complexity and uncertainty. The startle reflex was quantified, via electromyography, as the eyeblink following intense noise stimulation during the viewing of pleasant, neutral, and unpleasant emotional pictures. Forty-two healthy participants were classified according to their performance on the IGT using the median-split method. Overall, the startle amplitude was lower during pleasant and higher during unpleasant pictures than during neutral pictures. Participants with high IGT performance exhibited smaller response amplitudes than those with low IGT performance, independent of picture valence. Furthermore, inverse linear associations were seen between IGT performance and response amplitudes. The association between decision-making and startle reflex activity may be mediated by individual differences in emotional state. According to previous studies, a positive emotional state, as opposed to a negative emotional state, relates to smaller startle amplitudes and a preference for decision-making strategies based on intuition and body-related information (i.e., somatic markers), which are beneficial in situations involving complex and uncertain decisions. Moreover, an impact of individual differences in prefrontal cortex function on decision-making and startle reflex activity is feasible. The startle paradigm may be a useful tool to investigate interactions between bodily states and higher-order cognitive processing in future research.

Gender Differences in Prefrontal Cortex Response to Negative Emotional Stimuli in Drivers

BACKGROUND

Road safety improvement is a governmental priority due to driver-caused accidents. Driving style variation affects safety, with emotional regulation being pivotal. However, functional near-infrared spectroscopy (fNIRS) studies show inconsistent prefrontal cortex activity during emotion processing. This study examines prefrontal cortex response to negative emotional stimuli, particularly traffic accident images, across drivers diverse in age and gender.

METHOD

The study involved 118 healthy males (44.38 ± 12.98 years) and 84 females (38.89 ± 10.60 years). The Multidimensional Driving Style Inventory (MDSI) was used to assess driving behavior alongside fNIRS recordings. Participants viewed traffic accident and neutral images while prefrontal oxygenation was monitored.

RESULTS

Women rated traffic accidents (t-test = 2.43; p < 0.016) and neutral images (t-test = 2.19; p < 0.030) lower in valence than men. Arousal differences were significant for traffic accident images (t-test = -3.06; p < 0.002). correlational analysis found an inverse relationship between Dissociative scale scores and oxygenation (all p-values ≤ 0.013). Greater prefrontal oxygenation occurred with neutral images compared to traffic accidents. Left hemisphere differences (t-test = 3.23; p < 0.001) exceeded right hemisphere differences (t-test = 2.46; p < 0.015). Subgroup analysis showed male participants to be driving these disparities. Among adaptive drivers, significant oxygenation differences between neutral and accident images were evident in both hemispheres (left: t-test = 2.72, p < 0.009; right: t-test = 2.22, p < 0.030).

CONCLUSIONS

Male drivers with maladaptive driving styles, particularly dissociative ones, exhibit reduced prefrontal oxygenation when exposed to neutral and traffic accident images. This response was absent in female drivers, with no notable age-related differences.

Emoji-SP, the Spanish emoji database: Visual complexity, familiarity, frequency of use, clarity, and emotional valence and arousal norms for 1031 emojis

This article presents subjective norms for 1031 emojis in six dimensions: visual complexity, familiarity, frequency of use, clarity, emotional valence, and emotional arousal. This is the largest normative study conducted so far that relies on subjective ratings. Unlike the few existing normative studies, which mainly comprise face emojis, here we present a wide range of emoji categories. We also examine the correlations between the dimensions assessed. Our results show that, in terms of their affective properties, emojis are analogous to other stimuli, such as words, showing the expected U-shaped relationship between valence and arousal. The relationship between affective properties and other dimensions (e.g., between valence and familiarity) is also similar to the relationship observed in words, in the sense that positively valenced emojis are more familiar than negative ones. These findings suggest that emojis are suitable stimuli for studying affective processing. Emoji-SP will be highly valuable for researchers of various fields interested in emojis, including computer science, communication, linguistics, and psychology. The full set of norms is available at: https://osf.io/dtfjv/ .

Emojis Are Comprehended Better than Facial Expressions, by Male Participants

Emojis are colorful ideograms resembling stylized faces commonly used for expressing emotions in instant messaging, on social network sites, and in email communication. Notwithstanding their increasing and pervasive use in electronic communication, they are not much investigated in terms of their psychological properties and communicative efficacy. Here, we presented 112 different human facial expressions and emojis (expressing neutrality, happiness, surprise, sadness, anger, fear, and disgust) to a group of 96 female and male university students engaged in the recognition of their emotional meaning. Analyses of variance showed that male participants were significantly better than female participants at recognizing emojis (especially negative ones) while the latter were better than male participants at recognizing human facial expressions. Quite interestingly, male participants were better at recognizing emojis than human facial expressions per se. These findings are in line with more recent evidence suggesting that male individuals may be more competent and inclined to use emojis to express their emotions in messaging (especially sarcasm, teasing, and love) than previously thought. Finally, the data indicate that emojis are less ambiguous than facial expressions (except for neutral and surprise emotions), possibly because of the limited number of fine-grained details and the lack of morphological features conveying facial identity.

Physiological and affective responses to emoji faces: Effects on facial muscle activity, skin conductance, heart rate, and self-reported affect

The objective of the present study was to evaluate emotional responses to emoji faces through physiological and self-report measures, and evaluate possible differences between men and women. One hundred participants (50 women) observed pictures of happy, neutral, and angry emoji faces, while activity of the zygomatic and corrugator muscles, skin conductance, and heart rate were measured. Self-report measures of emotional experience were also recorded. The results showed an increase in zygomatic muscle activity toward happy emoji faces. An increasing trend in corrugator muscle activity toward angry emoji faces was observed; however, this trend was only marginally significant. Happy emoji faces generated an increase in the skin conductance response. The emotional experience of the participants was also consistent with the emotions that were expressed by the emoji faces. No differences were found between sexes. Overall, the results suggest that emoji faces can especially induce pleasant affective states.

The EmojiGrid as a Tool to Assess Experienced and Perceived Emotions

In a recent study on food-evoked emotions, we observed that people often misunderstood the currently available affective self-report tools. We, therefore, developed a new intuitive and language-independent self-report instrument called the EmojiGrid: a rectangular response grid labeled with facial icons (emoji) that express different degrees of valence and arousal. We found that participants intuitively and reliably reported their affective appraisal of food by clicking on the EmojiGrid, even without verbal instructions. In this study, we investigated whether the EmojiGrid can also serve as a tool to assess one’s own (experienced) emotions and perceived emotions of others. In the first experiment, participants (N = 90) used the EmojiGrid to report their own emotions, evoked by affective images from a database with corresponding normative ratings (obtained with a 9-point self-assessment mannikin scale). In the second experiment, participants (N = 61) used the EmojiGrid to report the perceived emotional state of persons shown in different affective situations, in pictures from a database with corresponding normative ratings (obtained with a 7-point Likert scale). For both experiments, the affective (valence and arousal) ratings obtained with the EmojiGrid show excellent agreement with the data provided in the literature (intraclass correlations of at least 0.90). Also, the relation between valence and arousal shows the classic U-shape at the group level. Thus, the EmojiGrid appears to be a useful graphical self-report instrument for the assessment of evoked and perceived emotions.

EmojiGrid: A 2D Pictorial Scale for the Assessment of Food Elicited Emotions

Research on food experience is typically challenged by the way questions are worded. We therefore developed the EmojiGrid: a graphical (language-independent) intuitive self-report tool to measure food-related valence and arousal. In a first experiment participants rated the valence and the arousing quality of 60 food images, using either the EmojiGrid or two independent visual analog scales (VAS). The valence ratings obtained with both tools strongly agree. However, the arousal ratings only agree for pleasant food items, but not for unpleasant ones. Furthermore, the results obtained with the EmojiGrid show the typical universal U-shaped relation between the mean valence and arousal that is commonly observed for a wide range of (visual, auditory, tactile, olfactory) affective stimuli, while the VAS tool yields a positive linear association between valence and arousal. We hypothesized that this disagreement reflects a lack of proper understanding of the arousal concept in the VAS condition. In a second experiment we attempted to clarify the arousal concept by asking participants to rate the valence and intensity of the taste associated with the perceived food items. After this adjustment the VAS and EmojiGrid yielded similar valence and arousal ratings (both showing the universal U-shaped relation between the valence and arousal). A comparison with the results from the first experiment showed that VAS arousal ratings strongly depended on the actual wording used, while EmojiGrid ratings were not affected by the framing of the associated question. This suggests that the EmojiGrid is largely self-explaining and intuitive. To test this hypothesis, we performed a third experiment in which participants rated food images using the EmojiGrid without an associated question, and we compared the results to those of the first two experiments. The EmojiGrid ratings obtained in all three experiments closely agree. We conclude that the EmojiGrid appears to be a valid and intuitive affective self-report tool that does not rely on written instructions and that can efficiently be used to measure food-related emotions.