Adolescent Aggression Research Articles

Ultrasound-Based Nomogram for Predicting the Aggressiveness of Papillary Thyroid Carcinoma in Adolescents and Young Adults

Assessing the aggressiveness of papillary thyroid carcinoma (PTC) preoperatively might play an important role in guiding therapeutic strategy. This study aimed to develop and validate a nomogram that integrated ultrasound (US) features with clinical characteristics to preoperatively predict aggressiveness in adolescents and young adults with PTC. In this retrospective study, a total of 2373 patients were enrolled and randomly divided into two groups with 1000 bootstrap sampling. The multivariable logistic regression (LR) analysis or least absolute shrinkage and selection operator LASSO regression was applied to select predictive US and clinical characteristics in the training cohort. By incorporating most powerful predictors, two predictive models presented as nomograms were developed, and their performance was assessed with respect to discrimination, calibration, and clinical usefulness. The LR_model that incorporated gender, tumor size, multifocality, US-reported cervical lymph nodes (CLN) status, and calcification demonstrated good discrimination and calibration with an area under curve (AUC), sensitivity and specificity of 0.802 (0.781-0.821), 65.58% (62.61%-68.55%), and 82.31% (79.33%-85.46%), respectively, in the training cohort; and 0.768 (0.736-0.797), 60.04% (55.62%-64.46%), and 83.62% (78.84%-87.71%), respectively, in the validation cohort. Gender, tumor size, orientation, calcification, and US-reported CLN status were combined to build LASSO_model. Compared with LR_model, the LASSO_model yielded a comparable diagnostic performance in both cohorts, the AUC, sensitivity, and specificity were 0.800 (0.780-0.820), 65.29% (62.26%-68.21%), and 81.93% (78.77%-84.91%), respectively, in the training cohort; and 0.763 (0.731-0.792), 59.43% (55.12%-63.93%), and 84.98% (80.89%-89.08%), respectively, in the validation cohort. The decision curve analysis indicated that using the two nomograms to predict the aggressiveness of PTC provided a greater benefit than either the treat-all or treat-none strategy. Through these two easy-to-use nomograms, the possibility of the aggressiveness of PTC in adolescents and young adults can be objectively quantified preoperatively. The two nomograms may serve as a useful clinical tool to provide valuable information for clinical decision-making.

The Moderating Effects of Internal-External Control on the Relationship Between Anger-in and Behavioral Displaced Aggression in Adolescents: Focusing on Gender Difference

The Moderating Effects of Internal-External Control on the Relationship Between Anger-in and Behavioral Displaced Aggression in Adolescents: Focusing on Gender Difference

청소년의 공격성에 영향을 미치는 요인

This study is a descriptive research study attempted to investigate the relationship between the degree of aggression, parent-child communication, self-concept, and loneliness in adolescents and to find out the factors that affect aggression. As a result of the study, parent-child communication, self-concept, and loneliness had a correlation with aggression. Regression analysis showed that communication with mother (t=-3.272, p<.001) and loneliness (t=2.579, p<.001) explained 18.2% of aggression. Based on the above research results, communication with the mother (t=-3.272, p<.001) and loneliness (t=2.579, p<.001) were identified as factors influencing adolescent aggression, and it is necessary to develop a program in which family can participate together while parents understanding their child's characteristics and communicate from the child's point of view.

The Mediating Effect of Academic Helplessness and Grit on the Effects of Adolescent Aggression on Life Satisfaction

The Mediating Effect of Academic Helplessness and Grit on the Effects of Adolescent Aggression on Life Satisfaction

The Effect of Islamic Maternal Parenting Style on Adolescent Aggressiveness by Modulating Peer Social Interaction

The verbal and non-verbal aggressiveness of adolescents has been increasing. It is a form of aggression that involves hostile and coercive actions towards others that may result in emotional or physical harm. This study aims to examine the Islamic parenting style of mothers, the primary caregivers in Javanese culture in Indonesia, as well as the social interactions with peers in relation to aggressive behavior. The participants of this study were 410 high school students aged between 15 and 19 years old (M = 16.52, SD = 0.793), consisting of 210 male students and 200 female students. Participants were selected from eight schools in Sleman City (4 senior high schools and four vocational high schools). The data was collected using the aggression scale, maternal parenting style, and social interactions with peers. Data were analyzed using Partial Least Square-Structural Equation Modeling (PLS-SEM) with Smart-PLS 4. The study results show a good fit model, indicating that aggression is influenced by Islamic maternal parenting style with social interactions with peers as a mediator. Social interactions have a mediating effect on the relationship between Islamic maternal parenting style and adolescent aggression. Another finding reveals that each Islamic maternal parenting style negatively affects aggression. Adolescent aggression can be controlled through Islamic maternal parenting style (i.e., authoritarian, authoritative, and permissive) and peer social interaction as a mediator.

Effects of sports intervention on aggression in children and adolescents: a systematic review and meta-analysis.

To explore the impact of sports on aggression in children and adolescents and analyze whether different conditions in the intervention, such as type of sports, or intervention duration, have different influences on the effect of interventions. The study protocol was registered in PROSPERO (CRD42022361024). We performed a systematic search of Pubmed, Web of Science, Cochrane library, Embase and Scopus databases from database inception to 12 October 2022 for all studies written in English. Studies were included if they met the following PICO criteria. All analyses were carried out using the Review Manager 5.3 Software. We summarized aggression, hostility and anger scores using SMDs. Summary estimates with 95% confidence intervals were pooled using DerSimonian-Laird random effects model or fixed effects model according to between-study heterogeneity. A total of 15 studies were deemed eligible for inclusion in this review. The overall mean effect size indicated that sport interventions was associated with lower aggression (SMD = -0.37, 95% CI [-0.69 to -0.06], P=0.020; I2=88%). Subgroup analyses showed that non-contact sports were associated with lower aggression (SMD = -0.65, 95% CI [-1.17 to -0.13], P=0.020; I2 = 92%) but high-contact sports were not (SMD = -0.15, 95% CI [-0.55 to 0.25], P=0.470; I2 = 79%). In addition, when intervention duration <6 months, sport interventions was associated with lower aggression (SMD = -0.99, 95% CI [-1.73 to -0.26], P=0.008; I2 = 90%) and when intervention duration ≥ 6 months, sport interventions was not associated with lower aggression (SMD = -0.08, 95% CI [-0.44 to -0.28], P=0.660; I2 = 87%). This review confirmed that sports intervention can reduce the aggression of children and adolescents. We suggested that schools can organize young people to participate in low-level, non-contact sports to reduce the occurrence of bullying, violence and other aggression-related adverse events. Additional studies are needed to determine which other variables are associated with aggression in children and adolescents, in order to develop a more detailed and comprehensive intervention programme to reduce their aggression.

Automatic Thoughts and Aggression among Adolescents

Abstract: The purpose of the present study is to assess the role of automatic thoughts on adolescents aggression. The study also assesses whether there are significant difference in gender with respect to aggression. A sample of 100 young adults (50 males, 50 females) aged between 15-22 years participated in the study. The Buss-Perry Aggression Questionnaire (BPAQ) by Drs. Arnold Buss and Robert Perry and the Automatic Thought Questionnaire 30 (ATQ 30) by Steven D. Hollon and Phillip C. Kendall were used to measure the variables in the study. The data were statistically analyzed using the independent sample t-test and Pearson's correlation coefficient. According to the results, aggression and automatic thinking are significantly positively correlated. Aggression in males and females does not significantly differ based on gender.

Bidirectional relationship between bullying victimization and functions of aggression in adolescents: The mediating effect of teacher justice.

Bullying victimization and aggression are frequent phenomena among adolescents and have been linked to various mental health problems. Although the correlation between bullying victimization and aggression is well-documented, the direction between the two has been debated. Moreover, the underlying mechanism through which victimization influences aggression or vice versa has gained little attention. The current study used data across two-time points to address this gap and explore the reciprocal relationships between victimization and aggression. The mediating role of teacher justice and related gender differences were also examined. A total of 2462 Chinese adolescents (50.9% boys; Mage = 13.95 years, SD = 0.60) completed measures on two occasions in 1 year with 6-month assessment intervals. Structural equation modeling was used to examine the longitudinal relations among the variables. Results found that bullying victimization significantly and positively predicted both reactive and proactive aggression over time among the total sample. Reactive aggression significantly positively predicted victimization, while proactive aggression negatively predicted victimization in boys. Furthermore, teacher justice mediated the relationships between victimization and both functions of aggression. Mediation was gender-specific, with a significant mediating effect on girls. The results reveal the violent cycle of bullying victimization and aggression and underscore the role of teacher justice in this process. These findings have important implications for targeted interventions.

Childhood maltreatment and homicidal ideation among Chinese early adolescents: The serial mediating role of borderline personality features and aggression.

A large body of evidence linked childhood maltreatment (CM) to juvenile violence and delinquent behavior. However, little is known about the association between CM and homicidal ideation in early adolescents. This study aimed to examine that relationship and to explore the serial mediating role of borderline personality features (BPF) and aggression in that relationship in a large sample of early adolescents. A total of 5724 early adolescents (mean age: 13.5 years) were recruited from three middle schools in Anhui Province, China. The participants were invited to complete self-report questionnaires regarding their history of CM, BPF, aggression, and homicidal ideation. Mediation analyses were evaluated using structural equation modeling. A total of 669 participants (11.7%) reported homicidal ideation in the past 6 months. CM victimization was positively associated with homicidal ideation after adjusting for covariates. Furthermore, the serial mediation analysis showed a significant indirect effect of CM on homicidal ideation through BPF and subsequent aggression. Exposure to maltreatment in childhood is likely to manifest BPF and subsequently higher levels of aggression, which in turn are related to increased homicidal ideation. These findings suggest the need for early intervention for BPF and aggression in early adolescents exposed to CM to prevent the development of homicidal ideation.

'Prosociality' in Daily School Life and Early Adolescents' Peer Aggression: A Multilevel Latent Profile Analysis Approach.

We aimed to typify prosocial characteristics of aggressive youth. We classified early adolescents based on daily configurations of prosocial behavior and autonomous prosocial motivations (performing prosocial behavior for identified and intrinsic reasons) and controlled prosocial motivations (performing prosocial behavior for external and introjected reasons) and explored the links between the obtained sub-groups and peer aggression. The sample included 242 Israeli six-graders [Mage = 11.96 (SD = 0.18), 50% girls] and their teachers. At the daily level, adolescents self-reported on prosocial behaviors and their autonomous and controlled prosocial motivations for ten consecutive days. At the trait level, adolescents reported on global, reactive, and proactive peer aggression. Teachers reported on adolescents' global peer aggression. Using multilevel latent profile analysis, we identified four day-level profiles of prosociality: 'high prosocial autonomous' (39% of days), 'low prosocial' (35%), 'average prosocial controlled' (14%), and 'high prosocial bi-motivation' (13%). At the adolescent level, we identified four sub-groups, each characterized by one dominant daily profile: 'stable high autonomy' (33% of adolescents); 'stable high bi-motivation' (12%); 'often average controlled' (16%); 'often low' (39%). Higher self-reported aggressive adolescents, particularly proactive aggressive, had the least chance of being in the 'stable high autonomy' sub-group of all sub-groups. Teacher-reported aggressive adolescents had the least likelihood of being in the 'stable high autonomy' sub-group and the most likelihood of being in the 'often low' sub-group. In sum, peer aggression is a function of the configured phenomenology of prosocial behavior and motivations, with high prosocial autonomously motivated youth being the least aggressive.

The prevalence of suicide attempt and suicidal ideation and its relationship with aggression and bullying in Chilean adolescents.

Suicide constitutes one of the main mental health problems worldwide, requiring detection, and prevention efforts, especially in the adolescent population. The purpose of this study was to estimate the prevalence of suicide attempts and suicidal ideation and their relationship with aggressiveness and bullying in Chilean adolescents. The sample was composed of 728 adolescents schooled from Arica city: 56.6% were males and 43.4% were females. The students attended from de 1st to the 4th year of secondary. The average age of the sample was 15,6 years. The following instruments were used: Okasha's Suicidality Scale, Buss and Perry's Aggressiveness Survey, and the Social Acceptance (School Bullying) sub-test of the Kidscreen-52 Survey. A cross-sectional, descriptive, and correlational design was applied. The sampling was non-probabilistic for convenience. 18.4% of the students reported that they had attempted suicide and 65.6% reported that they had suicidal ideation. The prevalence of suicide attempts was higher than in male adolescents (29,1% vs. 10,2%), and the same prevalence was for suicidal ideation (76,6% vs. 57,3%). Suicide attempts and suicidal ideation were positively and significantly correlated with aggressiveness (r = 0.32, r = 0.48) and bullying (r = 0.37, r = 0.50). The prevalence of suicide attempts and suicidal ideation is both higher in girls than boys. In this sense, girls constitute a risk group. In addition, this study provides evidence that supports the relationship between suicide attempts and suicidal ideation. The results highlight the role that educational institutions should have in terms of prevention and effective approaches.

Influence of Experience of Positive Commenting Activity (Sunfull) on Aggression and Hate Speech of Korean Adolescents

This study began in recognition of societal problems such as aggression and hate speech due to the spread of cyber-violence and malicious commenting. Hence, this study was conducted to verify whether positive commenting activity acts as a means of controlling adolescents’ aggression and hate speech. With this, a survey was conducted on 410 middle and high school students registered in the Sunfull Foundation. Consent from the organization's head, participant and research purpose anonymity, as well as data confidentiality, were all stated in advance taking the study's ethical considerations into mind. Frequency analysis and regression analysis were performed on the collected data using SPSS 22.0 PC ver. As a result, this study found that adolescents’ overall aggression decreased, and in particular, the more they participated in the positive commenting activity and the longer the period of participation in positive commenting, the lower the overt aggression of adolescents. These findings suggest that organizing positive commenting activities as one of the required subjects in the school curriculum may be a more useful strategy given the scenario that students in today's classrooms are in, which is one of continual academic pressure. Therefore, various support should be provided as well as social interest in the use of positive language as well as in the level of ethics education for adolescents.

Bullying, Cyberbullying, and Sexual Harassment Aggression in Spanish Adolescents: Common and Differential Risk Factors

ABSTRACT Bullying, cyberbullying, and sexual harassment are violent phenomena that co-occur in adolescence and across the lifespan. Exploring the common and differential factors of these interpersonal aggressions is essential to decreasing violence in schools. The present study built upon previous literature on the subject, including the moderating role of gender. Specifically, this study analyzed the role of moral disengagement, peer group pressure, anger management and empathy on bullying, cyberbullying, and sexual harassment aggression. In total, 897 Spanish adolescent students (50.10% girls) between 15 and 18 years old (M = 15.50, SD = 0.68) participated in a cross-sectional survey. Results showed that bullying, cyberbullying, and sexual harassment were all correlated. Greater levels of moral disengagement, peer group pressure, and lower anger management predicted all three types of aggressive behavior. Affective empathy was only related to sexual harassment. Multiple Group Analysis indicated no differences regarding associated factors on the basis of gender. Knowing the common and differential factors of these three types of interpersonal violence is crucial to comprehensively develop cross-cutting programs to address violence in schools.

Social, Psychological and Clinical Factors of Aggressive Behavior in Adolescents and Young People

Background : today, the problem of aggressiveness of teenagers and young people is becoming more and more urgent. The evidence confirms that violence in young people is becoming widespread, with negative social and economic consequences. It is known that aggression and aggressive behavior in young people is formed by the complex ontogenetic interaction of a variety of environmental factors, discovering a close relationship with suicide and suicidal tendencies. The development of effective measures to prevent severe forms of aggressive behavior has become a priority for the scientific community. Objective : to analyze the research studies of the phenomenon of aggression in adolescents and young people, to assess the impact of social, psychological and clinical factors on the level of aggressiveness in this age group. Materials and methods : according to the key words “teenage aggression”, “aggression factors”, “aggression psychology”, “aggression and suicide” conducted a search of publications in Medline/PubMed, Scopus, Web of Science, RISC and other sources for the last 20 years. Conclusion: increasing the level of aggression among adolescents and young people is a cross-cutting issue. Individual psychological characteristics, as well as some mental disorders, serve as background for the development of aggressive tendencies. A set of negative socio-economic factors contributes to the direct realization of the aggressiveness of the individual. The importance of environmental influence in the genesis of aggressive behavior indicates the need for integrative interaction of researchers with public organizations and law enforcement agencies in order to reduce the incidence of aggression among adolescents and young people.

Bulimia symptoms and anger and aggression among adolescents

BackgroundPrevious research has indicated that anger and aggression may be elevated in adolescents with a bulimia nervosa (BN) diagnosis. However, as yet, little is known about whether bulimia symptoms are linked to anger and aggression in adolescents in the general population. To address this deficit this study aimed to explore the associations between a clinical level of bulimia symptoms (CLBS) and anger, anger rumination and aggression in community-based adolescents, and determine whether gender is important in this context.MethodsThis study was conducted on a representative sample of youth from northwestern Russia (n = 2613, age 13–17 years old, 59.5% female) using self-report scales. A proxy variable for a CLBS was created using the Eating Disorder Diagnostic Scale. Aggression, anger and anger rumination were assessed by the Trait Anger Scale of the State Trait Anger Expression Inventory, the Anger Rumination Scale, and scales created to assess physically and verbally aggressive behavior. Multivariate analysis of covariance was used to examine the associations between the study variables.ResultsA CLBS was more prevalent in girls than in boys (13.4% vs. 3.5%). The association with anger and aggression was stronger in both genders with a CLBS, compared to those adolescents without a CLBS. In the CLBS group, boys as compared to girls scored higher on verbal and physical aggression, anger rumination and social aggression. In both the CLBS and Non-CLBS groups higher anger and aggression scores were associated with increasing age.ConclusionsFindings suggest that aggression and anger rumination are elevated in adolescents with BN symptoms, and that the associations between anger, aggression and BN symptoms may be stronger in boys. As previous research has indicated that the presence of aggressive behaviors may affect the prognosis of BN and complicate management of the disorder, clinician screening for these behaviors in adolescents with BN symptoms may facilitate the provision of more effective treatment, especially among boys.

Personality Traits and Aggressive Behavior in Vietnamese Adolescents.

This study aims to reveal the relationship between personality characteristics and verbal or physical aggression in Vietnamese adolescents. We recruited 3003 participants [1498 boys (49.9%) and 1505 girls (50.1%); mean age ± SD = 13.50 ± 0.936] who we tested with the Eysenck Personality Questionnaire - Brief version (EPQ-BV), and Vietnamese Aggression Scale (VAS). A multivariate analysis of variance test, Pearson Correlation, and analyzing mediating variable interaction is used to analyze data. The findings suggested a significant interaction between personality traits, specifically extraversion and neuroticism, and physical aggression, verbal aggression, and anger. Students with higher levels of personality had higher levels of verbal aggression, and students with higher levels of physical aggression and anger had stronger personality traits than others and lower levels of physical aggression and anger. Personality traits, specifically extraversion, and neuroticism, differed significantly by gender and school years in adolescence. Mediation analysis revealed a positive and statistically significant indirect correlation between personality traits and physically aggressive behavior, with anger as a mediator. Similarly, a positive and statistically significant indirect correlation between personality traits and verbally aggressive behavior through anger was found. The relationship between personality traits and physical aggression was also significant via verbal aggression and anger. This study improved our understanding of personality traits and verbal or physical aggression. Most crucially, physical and verbal aggression mediate personality traits and aggressive conduct. In secondary school, gender and school year affected extraversion and neuroticism. This discovery illuminates personality-based aggressiveness intervention.

Irritability and rejection-elicited aggression in adolescents and young adults.

Violence exacts staggering personal and financial costs - a burden disproportionally born by adolescents and young adults. This may be partially due to an increased sensitivity to social rejection during this critical phase of development. Irritability, a transdiagnostic symptom, is often elicited by social interactions. Yet, little is known about age differences in social rejection-elicited aggression and irritability. Progress toward testing such relations has been hindered by a lack of ecologically-valid tasks that enable the measurement of in-the-moment social rejection-elicited aggression. In this paper, we describe an initial study of young adults (n = 55) that demonstrates the efficacy of a novel Virtual School and Aggression Paradigm (VS-AP). Next, we replicate these results in a second study of adolescents and young adults (ages 11-25 years; n = 173) and examine relations between social rejection-elicited aggression, irritability, and age. We found that aggressive behavior in the VS-AP differed for accepting, rejecting, and unpredictable peer types (Study 1: F(2, 108) = 20.57, p < .001, ε2 = .28; Study 2: F(2, 344) = 152.13, p < .001, ε2 = .47), demonstrating that the VS-AP successfully models social rejection-elicited aggression. In Study 2, age was negatively correlated with aggressive behavior (r = -.29, p < .001) and irritability (r = -.28, p < .001), while irritability was positively correlated with aggressive behavior (r = .28, p < .001). Age moderated the relation between social rejection-elicited aggression and irritability. Specifically, irritability was more predictive of aggression in young adults than in adolescents (F(3, 167) = 7.07, p < .001). Data suggest mechanisms promoting rejection-elicited aggression may differ across development and vary for those with and without high levels of irritability. The VS-AP is a promising tool for probing neurocognitive, developmental, and clinically relevant mechanisms underlying social rejection-elicited aggression.

17. Cortical Volume Alterations in the Limbic Network and Reactive Aggression in Adolescents

17. Cortical Volume Alterations in the Limbic Network and Reactive Aggression in Adolescents

The relationship of leadership abilities with the aggressiveness of adolescents

The subject of this study was to identify the features of the relationship between leadership abilities and the aggressiveness of adolescents. The object of the study was the leadership abilities and aggressiveness of adolescents. The article presents the results of an empirical study to identify the relationship between leadership abilities and adolescent aggressiveness. The theoretical and methodological basis of the study were: - views on aggressiveness as an innate instinctive tendency (Z. Freud, K. Lorenz); personality property (A. Levitov, E. Fromm, etc.). - theoretical provisions on the causes of aggression in adolescence (B.S. Bratus, A.Ya. Varga, V.I. Garbuzov, I.S. Kon, E.A. Lichko, A.A. Rean, K. Horney and etc.). – theoretical principles of studying the leadership qualities of adolescents (I.P. Volkov, E.A. Gantseva, I.S. Kon, B.D. Parygin, A.I. Prigozhy, A.V. Petrovsky, R. Krichevsky). The theoretical significance and novelty of the study lies in the systematization of theoretical ideas about the features of the relationship between leadership abilities and the aggressiveness of adolescents. The practical significance is determined by the possibility of using the results obtained in schools for educational psychologists, for counseling psychologists who work with adolescents. Empirically, the psychological features of the relationship between leadership abilities and the aggressiveness of adolescents were revealed. With high indicators of leadership abilities, adolescents are dominated by high rates of verbal, object aggression and self-aggression; with average indicators of leadership abilities, adolescents show high rates of verbal, emotional aggression and self-aggression; Low leadership abilities of adolescents correspond to indicators of low emotional aggression. The results of this study indicate a statistically significant relationship between leadership abilities and adolescent aggressiveness. The results obtained in the study can be used to develop psycho-prophylactic and psycho-corrective programs aimed at correcting aggressive behavior and developing leadership abilities in adolescents.

Relationship between chronotypes and aggression in adolescents: a cross-sectional study

BackgroundThis study aimed to investigate the relationship between chronotypes and aggression in adolescents.MethodsA cross-sectional study was conducted on 755 primary and secondary school students aged 11–16 years in rural areas of Ningxia Province, China. The Chinese version of the Buss-Perry Aggression Questionnaire (AQ-CV) and the Chinese version Morningness-Eveningness Questionnaire (MEQ-CV) were used to assess the aggressive behavior and chronotypes of the study subjects. The Kruskal-Wallis test was then used to compare the differences in aggression among adolescents with different chronotypes, and Spearman correlation analysis to determine the relationship between chronotypes and aggression. Further linear regression analysis was used to investigate the effects of chronotype, personality traits, family environment, and class environment on adolescent aggression.ResultsThere were significant differences in chronotypes between different age groups and different sexes. Spearman correlation analysis showed that the MEQ-CV total score was negatively correlated with the AQ-CV total score (r = -0.263) and score of each AQ-CV subscale. In Model 1, chronotypes were negatively associated with aggression when controlling for age and sex, and evening-type adolescents might be more likely to exhibit aggressive behavior (b = -0.513, 95% CI: [-0.712, -0.315], P < 0.001); in Model 2, the negative association remained after controlling for family and class environment on the basis of Model 1 (b = -0.404, 95% CI: [-0.601, -0.208], P < 0.001); and in Model 3, the negative association still existed after controlling for personality traits on the basis of Model 2 (b = -0.383, 95% CI: [-0.577, -0.190], P < 0.001).ConclusionCompared to morning-type adolescents, evening-type adolescents were more likely to exhibit aggressive behavior. Given social expectations for MT adolescents, adolescents should be actively guided to develop a good circadian rhythm that may be more conducive to their physical and mental development.