A Comparative Study on Facially Expressed Emotions in Response to Basic Tastes

Taste the music: Modality-general representation of affective states derived from auditory and gustatory stimuli

Prior studies have extensively examined modality-general representation of affect across various sensory modalities, particularly focusing on auditory and visual stimuli. However, little research has explored the modality-general representation of affect between gustatory and other sensory modalities. This study aimed to investigate whether the affective responses induced by tastes and musical pieces could be predicted within and across modalities. For each modality, eight stimuli were chosen based on four basic taste conditions (sweet, bitter, sour, and salty). Participants rated their responses to each stimulus using both taste and emotion scales. The multivariate analyses including multidimensional scaling and classification analysis were performed. The findings revealed that auditory and gustatory stimuli in the sweet category were associated with positive valence, whereas those from the other taste categories were linked to negative valence. Additionally, auditory and gustatory stimuli in sour taste category were linked to high arousal, whereas stimuli in bitter taste category were associated with low arousal. This study revealed the potential mapping of gustatory and auditory stimuli onto core affect space in everyday experiences. Moreover, it demonstrated that emotions evoked by taste and music could be predicted across modalities, supporting modality-general representation of affect.

Spice up the moment: The influence of spicy taste on people's metaphorical perspectives on time

Embodied cognition contends that sensorimotor experiences undergird cognitive processes. Three embodied cross-domain metaphorical mappings constitute quintessential illustrations: spatial navigation and orientation underpin the conceptualization of time and emotion and gustatory sensation underlies the formulation of emotion. Threading together these strands of insights, the present research consisted of three studies explored the potential influence of spicy taste on people's metaphorical perspectives on time. The results revealed a positive correlation between spicy taste and the ego-moving metaphor for time such that individuals who enjoyed spicy taste (Study 1) and who consumed spicy (vs. salty) snack (Study 2) exhibited a predilection for the ego-moving perspective when cognizing a temporally ambiguous event. Because both spicy taste and the ego-moving metaphor are associated with anger and approach motivation, the latter two were postulated to be related to the novel taste-time relationship. Corroborative evidence for the hypothesis was found, which indicated that spicy (vs. salty) intake elicited significantly stronger anger toward and significantly greater approach-motivated perception of a rescheduled temporal event (Study 3). Taken together, the current findings demonstrate that spicy taste may play a role in people's perspectives on the movement of events in time and highlight the involved embodied interrelation between language, emotion, and cognition.

Specifics of the Emotional Response of Patients Suffering From Major Depressive Disorder to Imagined Basic Tastes of Food

Nowadays, the major depressive disorder (MDD) is a common disease that negatively affects the life quality of many people around the world. As MDD symptoms are closely related with the changes in food and eating, the relation between patients’ emotional responses and food tastes could be used as criteria for diagnostic. Until now, studies on the emotional response to different food tastes for patients affected by MDD have been poorly described in literature. Therefore, the aim of this study was to evaluate the emotional response of patients suffering from MDD to the imagined different food tastes and to compare the results with a control group. Emotional responses in tested participants were induced by using cards with words of basic food tastes such as “sweet,” “salty,” “bitter,” “sour,” and “neutral.” The assessment of emotional response was performed with FaceReader 6 software. The outcome of this study showed that participants with MDD expressed lower “happy” and “contempt” and higher “surprised” emotions, along with a higher negative valence mean, in comparison with controls for all tested basic tastes of food (p ≤ 0.05). When Likert scale was used, significant differences (p ≤ 0.001) in response were only found for “sour” and “salty” imaginary tastes between healthy group and patients with MDD. The findings of this study provide the additional data on food–associated emotion analysis of MDD patients and could be useful for the further development of the contactless method for early diagnosis of MDD.

Metacognition and Crossmodal Correspondences Between Auditory Attributes and Saltiness in a Large Sample Study

Mounting evidence demonstrates that people make surprisingly consistent associations between auditory attributes and a number of the commonly-agreed basic tastes. However, the sonic representation of (association with) saltiness has remained rather elusive. In the present study, a crowd-sourced online study ( n = 1819 participants) was conducted to determine the acoustical/musical attributes that best match saltiness, as well as participants' confidence levels in their choices. Based on previous literature on crossmodal correspondences involving saltiness, thirteen attributes were selected to cover a variety of temporal, tactile, and emotional associations. The results revealed that saltiness was associated most strongly with a long decay time, high auditory roughness, and a regular rhythm. In terms of emotional associations, saltiness was matched with negative valence, high arousal, and minor mode. Moreover, significantly higher average confidence ratings were observed for those saltiness-matching choices for which there was majority agreement, suggesting that individuals were more confident about their own judgments when it matched with the group response, therefore providing support for the so-called 'consensuality principle'. Taken together, these results help to uncover the complex interplay of mechanisms behind seemingly surprising crossmodal correspondences between sound attributes and taste.

A Multisensor Data Fusion Approach for Predicting Consumer Acceptance of Food Products

Sensory experiences play an important role in consumer response, purchase decision, and fidelity towards food products. Consumer studies when launching new food products must incorporate physiological response assessment to be more precise and, thus, increase their chances of success in the market. This paper introduces a novel sensory analysis system that incorporates facial emotion recognition (FER), galvanic skin response (GSR), and cardiac pulse to determine consumer acceptance of food samples. Taste and smell experiments were conducted with 120 participants recording facial images, biometric signals, and reported liking when trying a set of pleasant and unpleasant flavors and odors. Data fusion and analysis by machine learning models allow predicting the acceptance elicited by the samples. Results confirm that FER alone is not sufficient to determine consumers' acceptance. However, when combined with GSR and, to a lesser extent, with pulse signals, acceptance prediction can be improved. This research targets predicting consumer's acceptance without the continuous use of liking scores. In addition, the findings of this work may be used to explore the relationships between facial expressions and physiological reactions for non-rational decision-making when interacting with new food products.

The Facial Action Coding System for Characterization of Human Affective Response to Consumer Product-Based Stimuli: A Systematic Review

To characterize human emotions, researchers have increasingly utilized Automatic Facial Expression Analysis (AFEA), which automates the Facial Action Coding System (FACS) and translates the facial muscular positioning into the basic universal emotions. There is broad interest in the application of FACS for assessing consumer expressions as an indication of emotions to consumer product-stimuli. However, the translation of FACS to characterization of emotions is elusive in the literature. The aim of this systematic review is to give an overview of how FACS has been used to investigate human emotional behavior to consumer product-based stimuli. The search was limited to studies published in English after 1978, conducted on humans, using FACS or its action units to investigate affect, where emotional response is elicited by consumer product-based stimuli evoking at least one of the five senses. The search resulted in an initial total of 1,935 records, of which 55 studies were extracted and categorized based on the outcomes of interest including (i) method of FACS implementation; (ii) purpose of study; (iii) consumer product-based stimuli used; and (iv) measures of affect validation. Most studies implemented FACS manually (73%) to develop products and/or software (20%) and used consumer product-based stimuli that had known and/or defined capacity to evoke a particular affective response, such as films and/or movie clips (20%); minimal attention was paid to consumer products with low levels of emotional competence or with unknown affective impact. The vast majority of studies (53%) did not validate FACS-determined affect and, of the validation measures that were used, most tended to be discontinuous in nature and only captured affect as it holistically related to an experience. This review illuminated some inconsistencies in how FACS is carried out as well as how emotional response is inferred from facial muscle activation. This may prompt researchers to consider measuring the total consumer experience by employing a variety of methodologies in addition to FACS and its emotion-based interpretation guide. Such strategies may better conceptualize consumers' experience with products of low, unknown, and/or undefined capacity to evoke an affective response such as product prototypes, line extensions, etc.

An unfamiliar social presence reduces facial disgust responses to food stimuli

Consumers' emotional responses complement sensory and hedonic ratings in the prediction of food choice and consumption behaviour. The challenge with the measurement of consumption emotions is that emotions are highly context dependent. For emotion evaluations to bring greater insight to food research and development, it is essential that the influence of contextual variables on emotion are quantified. The present study contributes to the discussion with an investigation of the effect of an unfamiliar social presence on affective facial responses to visual food stimuli. Seventy participants (52 female and 18 male) viewed food images of varying acceptability either alone, or in the presence of the researcher. Subjective liking ratings were measured using a labelled affective magnitude scale, and facial muscle activity from zygomaticus major (contracted during smiling), corrugator supercilii (contracted during frowning) and levator labii superioris (contracted during nose wrinkling) were measured with an EMG recording system. Controlling for individual differences in facial expressivity and food image acceptability using linear mixed models, it was found that social context did not predict smiling or frowning muscle activity. Social context did predict the intensity of muscle activity indicative of a disgust response, with participants in the observed condition exhibiting less levator activity than participants in the alone condition. Regardless of social context, each muscle was found to have a relationship with subjective liking, with the direction of effects as expected. The results indicate that emotional stimuli and social context both influence food-evoked facial expression and provides support for the utility of facial EMG in measuring food-evoked emotion.

A Proximal Perspective on Disgust

The functional basis of disgust in disease avoidance is widely accepted; however, there is disagreement over what disgust is. This is a significant problem, as basic questions about disgust require knowing if single/multiple forms/processes exist. We address this issue with a new model with one form of disgust generated by multiple processes: (a) pure disgust experienced during gastrointestinal illness; (b) somatosensory disgust elicited by specific cues that activate the pure disgust state; (c) anticipatory disgust elicited by associations between distance cues for somatosensory disgust and requiring threat evaluation; (d) simulated disgusts elicited by imagining somatosensory and anticipatory disgust and frequently involving other emotions. Different contamination processes interlink (a–d). The implications of our model for fundamental questions about disgust (e.g., emotion status; continuation into animals) are examined.

Music to Make Your Mouth Water? Assessing the Potential Influence of Sour Music on Salivation

People robustly associate various sound attributes with specific smells/tastes, and soundtracks that are associated with specific tastes can influence people’s evaluation of the taste of food and drink. However, it is currently unknown whether such soundtracks directly impact the eating experience via physiological changes (an embodiment account), or whether they act at a higher cognitive level, or both. The present research assessed a version of the embodiment account, where a soundtrack associated with sourness is hypothesized to induce a physiological response in the listener by increasing salivary flow. Salivation was measured while participants were exposed to three different experimental conditions – a sour soundtrack, a muted lemon video showing a man eating a lemon, and a silent baseline condition. The results revealed that salivation during the lemon video condition was significantly greater than in the sour soundtrack and baseline conditions. However, contrary to our hypothesis, there was no significant difference between salivation levels in the sour soundtrack compared to the baseline condition. These results are discussed in terms of potential mechanisms underlying the auditory modulation of taste perception/evaluation.

Assessing the Role of Taste Intensity and Hedonics in Taste-Shape Correspondences

Taste liking influences the way in which people match tastes to shapes. However, taste-shape matching cannot be explained entirely by taste hedonics. Here, we assess whether variations in taste intensity influence such crossmodal correspondences. Participants were presented with five basic tastants in two concentrations and had to rate them on roundness/angularity shape scales, as well as in terms of liking, and intensity. The results revealed that taste quality, intensity, and participants' liking of the taste significantly predicted the roundness/angularity of the tastants. The results also revealed a positive correlation between perceived intensity and roundness/angularity for each of the tastants except sweet, and a negative correlation between liking and roundness/angularity for all of the tastes. These results are discussed in terms of the mechanism(s) that underlie the crossmodal correspondence between taste and shape.

"Turn Up the Taste": Assessing the Role of Taste Intensity and Emotion in Mediating Crossmodal Correspondences between Basic Tastes and Pitch

People intuitively match basic tastes to sounds of different pitches, and the matches that they make tend to be consistent across individuals. It is, though, not altogether clear what governs such crossmodal mappings between taste and auditory pitch. Here, we assess whether variations in taste intensity influence the matching of taste to pitch as well as the role of emotion in mediating such crossmodal correspondences. Participants were presented with 5 basic tastants at 3 concentrations. In Experiment 1, the participants rated the tastants in terms of their emotional arousal and valence/pleasantness, and selected a musical note (from 19 possible pitches ranging from C2 to C8) and loudness that best matched each tastant. In Experiment 2, the participants made emotion ratings and note matches in separate blocks of trials, then made emotion ratings for all 19 notes. Overall, the results of the 2 experiments revealed that both taste quality and concentration exerted a significant effect on participants' loudness selection, taste intensity rating, and valence and arousal ratings. Taste quality, not concentration levels, had a significant effect on participants' choice of pitch, but a significant positive correlation was observed between individual perceived taste intensity and pitch choice. A significant and strong correlation was also demonstrated between participants' valence assessments of tastants and their valence assessments of the best-matching musical notes. These results therefore provide evidence that: 1) pitch-taste correspondences are primarily influenced by taste quality, and to a lesser extent, by perceived intensity; and 2) such correspondences may be mediated by valence/pleasantness.