Subjects: Psychology >> Experimental Psychology submitted time 2023-06-25
Abstract： The facial width-to-height ratio (fWHR) is a stable perceptual structure of all faces. It is calculated by dividing the face width (the distance between the left and right zygion) by the face height (the distance between the eyebrow and the upper lip). Previous studies have demonstrated that men's facial width-to-height ratio is a reliable clue to noticing aggressive tendencies and behavior. Individuals with higher fWHR were considered by observers as more aggressive than those with lower fWHR. The researchers proposed that this may be related to facial expression. Observers more readily saw anger in faces with a relatively high fWHR and more readily saw fear in faces with a relatively low fWHR. However, it is unclear what the neural mechanism of fWHR is, particularly in the absence of attention. The present study investigated this issue by recording visual mismatch negativity (vMMN), which indicates automatic processing of visual information under unattended conditions.
Participants performed a size-change-detection task on a central cross, while random sequences of faces were presented in the background using a deviant-standard-reverse oddball paradigm. High fWHR faces (deviant stimuli) were presented less frequently among low fWHR faces (standard stimuli), or vice versa. Forty-one and twenty-five Chinese participated in Experiment 1 and 2, respectively. We hypothesized that faces with high fWHR would elicit a larger vMMN compared to faces with low fWHR. If the above result is related to the fact that high fWHR faces appear angrier and low fWHR faces appear more fearful, then high fWHR faces displaying an angry expression would evoke vMMN and low fWHR faces displaying a fearful expression would evoke vMMN.
In Experiment 1, faces with neutral expressions were used. The occipital-temporal vMMN emerged in the latency range of 200~500 ms for faces with high fWHR and in the latency range of 200~250 ms and 300~350 ms for faces with low fWHR. More importantly, faces with high fWHR elicited a higher vMMN than those with low fWHR faces in the 300~350 ms latency range. In Experiment 2, faces with expressions of fear and anger were used. Results showed that high-fWHR faces displaying an angry expression elicited a vMMN in the 200~250ms and 300~400ms latency ranges, while low-fWHR faces displaying a fearful expression elicited a vMMN in the 250~400ms latency range, especially in the left hemisphere. Comparing Experiment 1 and 2, we found that faces with high fWHR displaying an angry expression elicited smaller vMMN than those displaying a neutral expression.
In conclusion, the present findings suggest that the facial width-to-height ratio is associated with automatic processing and provide new electrophysiological evidence for the different mechanisms underlying high and low fWHR faces under unattended conditions. The results might be related to facial expressions. Consistent with previous studies, the current finding demonstrates that automatic processing of high and low fWHR is promoted by expressions of anger and fear, respectively. At the same time, due to the automatic processing of facial expressions, the automatic processing of faces with high fWHR was weakened by angry faces relative to neutral faces.
Subjects: Psychology >> Physiological Psychology submitted time 2023-06-19
Abstract： Stress contagion refers to the phenomenon where people unconsciously absorb stress reactions from another individual in the stressed state, through observation or direct contact, and match their own physiological and psychological state to that individual. The experimental paradigm for stress contagion can be categorized into two types: vicarious stress and stress crossover. In vicarious stress paradigms, the observer receives stress information transmitted through one or more sensory channels from a demonstrator. In stress crossover paradigms, the observer comes into direct contact with the demonstrator after they have experienced stress, receiving stress information through multiple sensory channels. The behavioral responses elicited by different sensory information exhibit similarities, such as decreased autonomic activity, increased anxiety-like behavior and elevated cortisol levels. The neural circuit and key brain regions involved are not entirely consistent across all sensory channels. However, stress contagion effects tend to be stronger when multiple sensory channels are involved compared to single sensory channels (visual, auditory, or olfactory). The amygdala has been identified as a central brain region for stress contagion, consistently demonstrating significant activation across various stress contagion paradigms. In future studies, it is crucial for researchers to carefully consider the experimental paradigms employed in studying stress contagion and identify specific brain regions of interest based on the underlying neural mechanisms associated with stress contagion effects induced by different sensory channels.
Subjects: Psychology >> Social Psychology submitted time 2023-03-28 Cooperative journals: 《心理科学进展》
Abstract： One of the core symptoms of autism spectrum disorder（ASD）is persistent social dysfunction. The severity of symptoms varies from patient to patient, and there are many different clinical manifestations, such as depression, anxiety, sleep disorders and ADHD. About 30 percent of people with ASD require psychotherapy and psychiatric care, including medication for behavioral problems. In recent years, many studies have indicated that tactile input can affect social function through regulating the oxytocin system. The affective touch conducted by C-fiber promotes the synthesis and release of oxytocin and enhances social motivation and social preference. And the social salience hypothesis of oxytocin hypothesizes that oxytocin regulates the attention orientation of individuals to social information cues in external situations. For example, oxytocin may enhance aggression and competitiveness of individuals in competitive situations while enhance cooperation in social situations. According to the social salience hypothesis of oxytocin, oxytocin increases the salience of social information through enhancing activation of corresponding brain regions. Under this theoretical framework, when social interaction happens, tactile input can enhance the synthesis and release of oxytocin, and oxytocin can also increase the salience of tactile information, which further promotes the occurrence of social interaction. Previous studies have shown that people with ASD have deficits in the oxytocin system. The main manifestations are lower peripheral oxytocin concentration than normal developing individuals and the change of Single Nucleotide Polymorphism（SNP）of oxytocin receptor. People with ASD also show abnormal tactile sensitivity, including hypersensitivity and hyposensitivity. At the peripheral level, they manifest abnormal tactile threshold. At the central level, they manifest abnormal activation in the brain’s affective touch processing regions (such as insula). Compared with typical development, people with ASD show lower activation in social brain network, which maybe is the one reason of abnormal tactile sensitivity. Moderate tactile input can promote the synthesis and release of oxytocin. Thus, we can combine the exogenous oxytocin treatment with auxiliary tactile training together in the future intervening measures. And the interventions for social dysfunction need to start as early as possible. Many people with ASD exhibit abnormal sensory sensitivity in early life, which can affect the quality of parent-child interactions. If infant cannot obtain adequate sensory input from early parent-child interaction, it will cause a growth environment similar to sensory deprivation for infant patients with ASD, which will seriously affect future social functioning in adulthood. Based on the social salience hypothesis of oxytocin, this article summarizes the possible regulations between touch and oxytocin on social function. We point out that the deficits in the oxytocin system can decrease the salience of touch information in people with ASD, reducing the attention resources in social interaction and affecting the emotional feelings for touch. Abnormal tactile sensitivity results in social avoidance, which decreases the synthesis and release of oxytocin in social contact, decreasing the social motivation and social preference, ultimately resulting in social dysfunction. Exploring the interaction between touch, oxytocin system and social function can help us understand the pathogenesis of social dysfunction, and providing new ideas for the prevention and intervention in the future.
Subjects: Psychology >> Physiological Psychology Subjects: Psychology >> Medical Psychology submitted time 2022-12-28
Abstract：
One of the core symptoms of autism spectrum disorder (ASD)is persistent social dysfunction. In recent years, many studies have indicated that tactile input can affect social function through regulating the oxytocin system. The affective touch conducted by C-fiber promotes the synthesis and release of oxytocin and enhances social motivation and social preference. According to the social salience hypothesis of oxytocin, oxytocin increases the salience of social information through enhancing activation of corresponding brain regions. Under this theoretical framework, when social interaction happens, tactile input can enhance the synthesis and release of oxytocin, and oxytocin can also increase the salience of tactile information, which further promotes the occurrence of social interaction. Previous studies have shown that people with ASD have deficits in the oxytocin system. The main manifestations are lower peripheral oxytocin concentration than normal developing individuals and the change of Single Nucleotide Polymorphism (SNP)of oxytocin receptor. People with ASD also show abnormal tactile sensitivity, including hypersensitivity and hyposensitivity. At the peripheral level, they manifest abnormal tactile threshold. At the central level, they manifest abnormal activation in the brain’s affective touch processing regions (such as insula). Based on the social salience hypothesis of oxytocin, this article summarizes the possible regulations between touch and oxytocin on social function. We point out that the deficits in the oxytocin system can decrease the salience of touch information in people with ASD, reducing the attention resources in social interaction and affecting the emotional feelings for touch. Abnormal tactile sensitivity results in social avoidance, which decreases the synthesis and release of oxytocin in social contact, decreasing the social motivation and social preference, ultimately resulting in social dysfunction. Exploring the interaction between touch, oxytocin system and social function can help us understand the pathogenesis of social dysfunction, and providing new ideas for the prevention and intervention in the future.
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