Act generously when others do so: Majority influence on young children's sharing behavior.

Children's sharing behavior is profoundly shaped by social norms within their society, and they can learn these norms by directly observing how most others share in their immediate environment. Here we systematically investigated the impact of majority influence on the sharing behavior of young Chinese children through three studies (N = 336, 168 girls). Four- and 6-year-olds were allowed to choose 10 favorite stickers and had an opportunity to engage in anonymous sharing. Before making the sharing decision, children were assigned to one of two conditions: watching a video in which three peers all shared 8 out of 10 stickers (i.e., the majority sharing condition) or making their decisions without watching the video (i.e., the control condition). Results showed that both the 4- and 6-year-old children shared more stickers in the majority sharing condition than in the control condition (Studies 1 & 2). Moreover, the influence of the majority had a stronger effect compared to the influence of a single role model. Children shared more stickers after observing three peers sharing, compared to watching one peer sharing three times (Study 2). Furthermore, children were less likely to copy the majority's non-sharing behavior when it came to giving away stickers without prosocial outcomes, which was particularly evident among 4-year-olds (Study 3). The results reveal that majority influence uniquely shapes children's sharing behavior and that children selectively follow the majority based on whether the behavior exhibits prosocial attributes. A video abstract of this article can be viewed at https://youtu.be/8qNNhf9754I?si=7YfpaFpcD_IjlXjJ RESEARCH HIGHLIGHTS: Observing a majority of three peers' unanimous generous sharing promoted sharing behavior in both 4- and 6-year-olds. The influence of three peers on children's sharing was stronger than that of one peer sharing three times. Four-year-olds, but not 6-year-olds, did not copy the non-sharing behavior of the majority as it did not lead to prosocial outcomes.

Preschoolers' ingroup bias in predicting others' sharing: The role of contexts and theory of mind.

The current study investigated preschoolers' ingroup bias in predicting people's sharing across contexts and its relation to second-order theory of mind (ToM) ability. In Experiment 1, 96 5- and 6-year-old children were assigned to one of two groups in a minimal group paradigm. They heard a story about fictional ingroup and outgroup peers sharing in a public or private condition and were asked to predict and evaluate their sharing behavior. Children predicted that ingroup peers would share more than outgroup peers and also showed ingroup bias in evaluation regardless of the equal actual sharing of ingroup and outgroup peers. Moreover, 6-year-olds displayed a flexible ingroup bias in predicting others' sharing across conditions because they held such a bias only in public conditions and did not expect ingroup and outgroup peers to share differently in private conditions. Experiment 2 tested a new sample of 80 6-year-olds with the same sharing story and a second-order false belief task. Results showed that only 6-year-olds who fully passed the false belief task showed a flexible bias in predicting sharing across conditions. Results indicate that children's ingroup bias in predicting others' sharing is becoming flexible across contexts as they grow up and ToM skills contribute to the development of their increasingly sophisticated prosocial reasoning.

Interaction between a serotonin transporter gene promoter region polymorphism and stress predicts depressive symptoms in Chinese adolescents: a multi-wave longitudinal study.

BACKGROUND: The serotonin transporter (5-HTT) gene may play an important role in the onset and development of mental disorders. Past studies have tested whether a functional polymorphism in the 5-HTT gene linked promoter region (5-HTTLPR) moderated the association between stress and depressive symptoms, but the results of these studies were inconsistent. Thus, the aim of the current study was to examine the interaction between 5-HTTLPR and stress that predict depressive symptoms in Chinese adolescents. METHODS: A total of 252 healthy adolescents (131 females and 121 males, aged from 14 to 18, mean = 16.00, standard deviation = 0.60) participated in this study. During the initial assessment, all participants completed the Center for Epidemiological Studies Depression Scale (CES-D) and Adolescent Life Events Questionnaire (ALEQ) and were genotyped for the 5-HTTLPR polymorphism. Participants subsequently completed CES-D and ALEQ once every three months during the subsequent 24 months. A multilevel model was used to investigate the 5-HTTLPR × stress interaction in predicting depressive symptoms. RESULTS: The results indicated no main effect of 5-HTTLPR and a significant 5-HTTLPR × stress interaction in females only. Females with at least one 5-HTTLPR S allele exhibited more depressive symptoms under stressful situations. No significant 5-HTTLPR × stress interaction was found in males. CONCLUSIONS: In Chinese adolescents, there are gender differences on the interaction between 5-HTTLPR and stress that predict depressive symptoms. The association between stress and depressive symptoms is moderated by 5-HTTLPR in Chinese female adolescents.

Chinese preschoolers' resource allocation in the face of existing inequality under collaborative and noncollaborative contexts.

The current study investigated the stage at which Chinese preschoolers started considering recipients' material welfare and minimizing existing inequalities under both noncollaborative and collaborative contexts. Also, it analyzed how they behaved when recipients' material welfare was in conflict with merit or equality rule. Experiment 1 found that 4-year-old children allocated resources to the poor rather than the rich character only under the noncollaborative context but not under the collaborative context, in which they had observed these 2 characters working together to finish a task. By contrast, 5-year-old children started doing so under both collaborative and noncollaborative contexts. When there was conflict between recipients' material welfare and merit in Experiment 2, 6-year-old children did not show any preference for either material welfare or merit, and they made equal or almost equal distributions. Without collaboration information, Experiment 3 further revealed that the children aged from 4 to 6 y preferred equal distribution to resource allocation considering recipients' material welfare. These findings have been discussed in terms of contextual information and cultural influences. (PsycINFO Database Record

[Beneficial effect of periodontal therapy on insulin resistance and lipid metabolism in obese rats with periodontitis].

OBJECTIVE: To investigate the effect of periodontal therapy in controlling periodontitis and on insulin resistance and lipid metabolism in obese rats with periodontitis. METHODS: Sprague-Dawley rats were randomized into normal group (group C), obese group (group O), periodontitis combined with obesity group (group P) and periodontal treatment group (group T). The obese rats in groups P and T were subjected to ligation of the maxillary second molar with silk thread to induce experimental periodontitis, and the rats in group T received periodontal therapy after the ligation. All the rats were sacrificed at the age of 24 weeks for measurement of blood lipids, insulin and blood glucose levels, and insulin resistance index (HOMA-IR) was calculated. The expressions of insulin receptor substrate-1 (IRS-1) and IRS-2 in the liver tissues were detected using real-time quantitative polymerase chain reaction (RT-PCR). RESULTS: Compared with the obese rats in group O, the rats in group P showed significantly higher HOMA-IR and LDL-C and lower expressions of IRS-1 and IRS-2 mRNA expression and HDL-C level (P<0.05). Compared with those in group P, the mRNA expressions of IRS-1 and IRS-2 and HDL-C level were significantly increased and LDL-C level, TC level and HOMA-IR were all decreased in group T (P<0.05), but the level of TG was comparable between the two groups. Pathological examination revealed lessened inflammatory cell infiltration and tissue destruction in the upper jaw of the rats in group T; the rats in group P presented with the most obvious upper jaw destruction and steatosis and inflammatory cell infiltration in the liver. CONCLUSION: Periodontal inflammation can downregulate the expression of IRS-1 and IRS-2 and increase insulin resistance and dyslipidemia in obese rats. Periodontal therapy produces a beneficial effect in improving insulin resistance and reducing dyslipidemia in obese rats.

[Effects of non-surgical periodontal therapy on serum inflammatory markers and metabolic level in obese rats].

OBJECTIVE: To investigate the effects of non-surgical periodontal therapy on serum inflammatory factors and metabolism levels in obese rats with experimental periodontitis. METHODS: Sixteen obese rats with experimental periodontitis were randomly divided into treatment group and control group with non-surgical periodontal therapy and no treatment, respectively. Oral glucose tolerance test was performed before treatment and 2 weeks after the treatment. All the rats were sacrificed 2 weeks after treatment and the orbital vein blood was taken to detect fasting blood glucose, fasting insulin, and serum level of C-reactive protein (CRP). Results Two weeks after periodontal treatment, fasting blood glucose (t=2.445, P=0.034) and beta cell function index (t=-2.543, P=0.027) were significantly lower in the treatment group than in the control group. Compared with those in the control group, CRP level (t=2.388, P=0.028) and the area under the curve in the oral glucose tolerance test (t=12.053, P=0.000) decreased significantly in the treatment group. CONCLUSION: Non-surgical periodontal treatment can reduce serum CRP level and improve glucose metabolism in obese rats.

Gene-Gene-Environment Interactions of Serotonin Transporter, Monoamine Oxidase A and Childhood Maltreatment Predict Aggressive Behavior in Chinese Adolescents.

Gene-environment interactions that moderate aggressive behavior have been identified independently in the serotonin transporter (5-HTT) gene and monoamine oxidase A gene (MAOA). The aim of the present study was to investigate epistasis interactions between MAOA-variable number tandem repeat (VNTR), 5-HTTlinked polymorphism (LPR) and child abuse and the effects of these on aggressive tendencies in a group of otherwise healthy adolescents. A group of 546 Chinese male adolescents completed the Child Trauma Questionnaire and Youth self-report of the Child Behavior Checklist. Buccal cells were collected for DNA analysis. The effects of childhood abuse, MAOA-VNTR, 5-HTTLPR genotypes and their interactive gene-gene-environmental effects on aggressive behavior were analyzed using a linear regression model. The effect of child maltreatment was significant, and a three-way interaction among MAOA-VNTR, 5-HTTLPR and sexual abuse (SA) relating to aggressive behaviors was identified. Chinese male adolescents with high expression of the MAOA-VNTR allele and 5-HTTLPR "SS" genotype exhibited the highest aggression tendencies with an increase in SA during childhood. The findings reported support aggression being a complex behavior involving the synergistic effects of gene-gene-environment interactions.

[Construction of gtfB/CAT eukaryotic expression plasmid of Streptococcus mutans in mammalian cells].

PURPOSE: The study aimed to evaluate the expression of recombinant plasmid pVAX1- gtfB/CAT in mammalian COS-7 cells. METHODS: The eukaryotic plasmid carrying encoding gene of gtfB/CAT of Streptococcus mutans was constructed and introduced into COS-7 cells by lipofectamine reagent. The transient protein expression was detected by immunochemistry technique in COS-7 cells. RESULTS: The positive expression of gefB/CAT was detected in plasma of the cells which were transfected with recombinant plasmid pVAX1- gtfB/CAT. The cells which were transfected with pVAX1 were negative for gtfB/CAT expression. CONCLUSIONS: GtfB/CAT can be translated and expressed in COS-7 cells after transfected with recombinant plasmid pVAX1- gtfB/CAT. The expressed protein is located in the plasma and the protein is able to combine with anti- gtfB/CAT antibody. The expressed protein has the antigenicity and recombinant plasmid pVAX1- gtfB/CAT is a candidate vaccine.Supported by Key Research Project of Bureau of Education of Guizhou Province (Grant No.2004119).