In school, shyness is associated with psychosocial difficulties and has negative impacts on children’s academic performance and wellbeing. Even though there are different strategies and interventions to help children deal with shyness, there is currently no comprehensive systematic review of available interventions. This systematic review and meta-analysis aim to identify interventions for shy children and to evaluate the effectiveness in reducing psychosocial difficulties and other impacts. The methodology and reporting were guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement and checklist. A total of 4,864 studies were identified and 25 of these met the inclusion criteria. These studies employed interventions that were directed at school-aged children between six and twelve years of age and described both pre- and post-intervention measurement in target populations of at least five children. Most studies included an intervention undertaken in a school setting. The meta-analysis revealed interventions showing a large effect in reducing negative consequences of shyness, which is consistent with extant literature regarding shyness in school, suggesting school-age as an ideal developmental stage to target shyness. None of the interventions were delivered in a classroom setting, limiting the ability to make comparisons between in-class interventions and those delivered outside the classroom, but highlighting the effectiveness of interventions outside the classroom. The interventions were often conducted in group sessions, based at the school, and involved activities such as play, modelling and reinforcement and clinical methods such as social skills training, psychoeducation, and exposure. Traditionally, such methods have been confined to a clinic setting. The results of the current study show that, when such methods are used in a school-based setting and involve peers, the results can be effective in reducing negative effects of shyness. This is consistent with recommendations that interventions be age-appropriate, consider social development and utilise wide, school-based programs that address all students.
Citation: Cordier R, Speyer R, Mahoney N, Arnesen A, Mjelve LH, Nyborg G (2021) Effects of interventions for social anxiety and shyness in school-aged children: A systematic review and meta-analysis. PLoS ONE 16(7): e0254117. https://doi.org/10.1371/journal.pone.0254117
Editor: Thomas M. Olino, Temple University, UNITED STATES
Received: February 9, 2021; Accepted: June 20, 2021; Published: July 9, 2021
Copyright: © 2021 Cordier et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant information is within the manuscript.
Funding: The work was conducted using funding from an internal grant, granted by the University of Oslo, Department of Special Needs Education. The funder had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. Authors who are employed by University of Oslo do receive a salary from the University.
Competing interests: The authors have declared that no competing interests exist.
Shyness is commonly experienced by school-aged children . Despite being a frequently used term, there is a diversity of constructs that underpin ‘shyness’, including behavioural inhibition, social reticence, social withdrawal, anxious solitude and social anxiety . There have been several approaches to defining shyness in the past. Some conceptualisations theorise shyness as either behavioural inhibition to the unfamiliar (i.e., wariness in unfamiliar situations) or social withdrawal [i.e., elevated rates of solitary behaviour or symptoms of social anxiety disorder; 3–7]. In contrast, substantial literature has investigated shyness as encompassing individual differences in wariness or anxiety in novel situations, embarrassment or self-conscious in anticipation of social evaluation and reticence in social situations . Shyness has also been considered from a developmental perspective, proposing an interactional child-by-environment model. By this model, behavioural inhibition and social withdrawal are considered risk factors for further social anxiety. Interactions between the child and the environment, and the child and their parents and peers, can either promote or diminish the risk of later anxiety [4,8,9].
Taxonomy of shyness
In order to organise and operationalise the various concepts of shyness in use, Rubin, Coplan  proposed a taxonomy of shyness. This taxonomy places behavioural solitude (i.e., lack of interaction in presence of peers) as the over-arching, observable behaviour of shyness. The source of this solitude is either internal, termed social withdrawal (i.e., removing oneself from social interaction) or external, termed active isolation (i.e., being excluded by others). If the source is internal (i.e., social withdrawal), the motivation for withdrawal is either by preference, termed social disinterest, or a result of fear or wariness. The source of fear is then split into four categories: 1) behaviour inhibition (i.e., fear of novelty); 2) anxious solitude (i.e., wariness in familiar social situations); 3) shyness (i.e., wariness of social novelty and/or perceive evaluation); and 4) social reticence (i.e., observed display of onlooker behaviours). In this taxonomy, these fears and behaviours can become clinically significant over time and manifest as a social anxiety disorder. This taxonomy provides a clear conceptualisation of shyness and social anxiety, and outlines observable behaviours, sources, motivations and specific fears.
Shy children in school
In addition to the potential manifestation of social anxiety disorder theorised by Rubin, Coplan , children with shyness may also experience a range of other difficulties that, although not clinically diagnosable, can vastly impact their wellbeing, social networks and academic performance . Many of these difficulties are experienced at school, where peer interactions are an integral component of the environment. Shy children are often quiet across a range of situations in school, both in the classroom and in social situations . Talking, in or outside of class, can make a child the centre of attention and open to social evaluation, which sits at the centre of the taxonomy of shyness. Shy children have fewer in-class interactions and respond less often to direct or class-wide questions than their non-shy peers . Research has shown that shy children often have lower academic attainment, poorer performance on tests of language development, and are more likely to have difficulty adjusting at school .
Shyness is also associated with psychosocial challenges in school. Shy children often have a limited number of friends and are at risk of peer victimisation and exclusion [7,13]. They may also use social withdrawal as a way to avoid or cope with peer victimisation . Shyness is positively associated with somatic complaints, school-related stress, anxiety and depressive symptoms [15,16]. Shyness can increase over time, predicting difficulties later in adolescence . Shy children often have poor social skills and high levels of anxiety and depression symptoms in early adolescence . Longitudinal studies show that shyness and social withdrawal are significant risk factors for social anxiety disorder [8,18]. These results are aligned with the Rubin, Coplan  taxonomy of shyness and social anxiety, demonstrating the theorised pathway to social anxiety disorder.
School-based interventions for shy children
Given the short- and long-term psychosocial and academic outcomes for shy children, there have been multiple attempts at buffering the impacts of shyness. In the classroom, teachers can use concepts, such as shyness, as a tool to tailor how they work with an individual child . Teachers at a Norwegian elementary school broadly categorised shy children in their classroom as either, 1) withdrawn, 2) anxious, and/or 3) having poor self-esteem. These categories then informed the support given to the individual child, including cognitive support and feedback and encouraging active learning . Informal, teacher-facilitated support or intervention is a common response to shyness within the classroom, as teachers recognise shy children and the potential problems they encounter [20–22]. Teachers report employing social learning strategies, such as verbal encouragement, praise and modelling behaviour, as well as peer-focused strategies to promote inclusion, such as encouraging joint activities . However, the effectiveness of these individual attempts is limited to within the classroom and may not impact poor psychosocial outcomes for shy children in broader contexts.
Beyond classroom support, there are many different structured interventions targeting shyness in school-aged children. Clinical interventions are typically conducted in non-naturalistic settings with homework-style practice in naturalistic settings, and comprise of social skills training, psychoeducation, cognitive restructuring and exposure tasks . Criticisms of this approach are that such interventions do not consider nor change the environment itself and focus on treating social anxiety disorders, ignoring shyness more broadly . Clinical interventions need to be age-appropriate and consider cognitive and social development, social context and parent involvement . As shy children are often excluded or victimised by their peers, interventions need to consider the environment and peer interaction. Developmental interventions include peers in the intervention itself, aiming to increase the use of successful social skills in naturalistic settings . However, this approach requires school resources and willingness of peers to be involved. Crozier  suggests that a focus on individual screening and pathologising shyness may not lead to effective intervention, as not all shy children develop anxiety disorders. Wider, school-based programs that address all student’s social confidence, instead of targeted interventions, may be more suitable intervention for shyness . Given the wide range of intervention approaches and intervention programs themselves, there is no clear best-practice for interventions for shy children. This is further complicated by inconsistent use of terminology related to shyness .
To reduce academic and concomitant psychosocial difficulties in school for shy children, there is a need for effective, feasible interventions. To date, there is no comprehensive systematic review of the available interventions for shy children. This systematic review and meta-analysis aim to provide an overview of the available interventions for shy children aged six to twelve years, describe the characteristics of the interventions, summarise intervention strategies being used, and determine their overall effectiveness, as well as effectiveness of interventions in relation to the following domains: 1) setting where the interventions is delivered; 2) mode of delivery; 3) intervention focus; and 4) rater of outcome measures.
The methodology and reporting on this systematic review were guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and checklist. The PRISMA statement and checklist supports researchers in the critical and transparent reporting of systematic reviews in areas of health care [24,25].
[The PRISMA checklist is provided as Supporting Information].
To be eligible for inclusion in this systematic review, studies were required to describe an intervention in school-aged children (between six and twelve years old) for social anxiety and shyness. Only studies describing both pre- and post-intervention measurement in target populations of at least five children were included. Only original articles published in English were considered for eligibility. Conference abstracts, case reports, reviews, student dissertations and editorials were excluded.
Data sources and search strategies
Literature searches were conducted in five electronic databases: CINAHL, Embase, Eric, PsycINFO and PubMed. All publication dates up to 23rd December 2020 were included. The search strategies per database are listed in Table 1.
Methodological quality and level of evidence
The Qualsyst critical appraisal tool by Kmet  and the National Health and Medical Research Council (NHMRC) Evidence Hierarchy Levels of Evidence  were used to assess the methodological quality of the included studies: I (systematic review of level II studies); II (randomised controlled trial); III-1 (pseudo-randomised controlled trial); III-2 (comparative study with concurrent controls); III-3 (comparative study without concurrent controls); IV (case series with either post-test or pre-post outcomes). The Qualsyst tool provides a systematic, reproducible and quantitative means of appraising the methodological quality of research across a broad range of study designs. The Qualsyst consists of 14 items. All items have a three-point ordinal scoring (yes = 2, partial = 1, no = 0). A total score can be converted into a percentage score. A score above 80% is considered strong quality, a score of 60 to 79% considered good, a score of 50 to 59% considered adequate, and a score below 50% considered poor quality. Studies with poor study quality were excluded from further analysis in this review.
A data extraction form was created to extract data from the included studies under the following categories: study design (according to NHMRC level), methodological quality (Qualsyst), participants (numbers, groups), age (range, mean, standard deviation), gender, intervention, inclusion criteria of the individual study (if stated), outcome measures and treatment outcomes. To ensure the meta-analysis focused on factors that impact on shyness, authors identified and extracted only data collected using the main outcome measure related to shyness (see Table 2). Due to the lack of dedicated shyness outcome measures in literature, the most suitable outcome measure related to shyness was chosen. Data including means, standard deviations, and sample sizes were extracted from the included studies to enable the calculation of the overall effect of shyness interventions (within-group pre-post intervention comparisons), and comparisons between shy children and control groups (between-group experimental vs. control intervention group comparisons).
Data items, risk of bias and synthesis of results
Risk of bias in the included studies was assessed at an individual study level using the Kmet appraisal checklist . Risk of bias was minimised in this process by having a full overlap between independent abstract and article reviewers, and by two independent assessors independently scoring 100% of the methodological quality of included studies. Final study selection and quality assessment were the result of consensus-based ratings. Discrepancies were resolved by involving a third reviewer. No author of this review was affiliated with any of the included studies. Extracted data were synthesised in relation to the methodological characteristics of each included study and the findings of individual studies with regards to the treatment outcomes of shyness interventions.
Using the extracted data from the main outcome measure related to shyness, estimates were calculated of pooled effect sizes weighted by sample size using random-effects models for summary statistics. To determine potentially confounding variables, effect sizes of shyness interventions were grouped by setting (school, clinic and/or home), focus (child and/or parents), mode of delivery (individual and/or group sessions), and rater of outcome measures (child, parents, clinician and/or teacher). The Hedges-g formula for standardized mean difference (SMD) with a 95% confidence interval (95% CI) was used to report effect sizes. A test for overall effect for each intervention setting, mode, focus and outcome rater produced a weighted effect size (z). Tests for heterogeneity were conducted to identify inconsistency in treatment effects, included I2 and chi-square (Q). All statistical analyses were performed using software package Comprehensive Meta-Analysis Version 3.3.070 (Biostat; Englewood, NJ, USA).
Within-groups effects were examined by analysing the pre-post data for studies both with and without control groups. The benefit of within-groups analyses is that it allows the examination of the effect of an intervention in and of itself, without controls. Between-groups analyses (comparing results of control group to that of intervention group) were also conducted. This allows comparison of different forms of interventions against each other.
A total of 4,864 articles were identified (CINAHL: n = 605, Embase: n = 1158, ERIC: n = 1849, PsycINFO: n = 968 and PubMed: n = 929). After the removal of duplicate articles, 5299 abstracts were screened. A total of 149 studies were assessed at a full text level for eligibility. Of these, 129 were excluded and 20 were included (see Fig 1). No studies were excluded due to poor quality. An additional five studies were included through searching the reference lists of the 20 studies that met the inclusion criteria. This resulted in a total of 25 included studies.
Participants of studies included in the systematic review.
The total number of participants across the 25 included studies was 1,895, with the average participants across studies 75.8. Griffin, Caldarella  had the largest sample of 388 participants and Cook, Xie  the smallest sample of 5 participants. The average age of total participants across the studies was 9.1 years (SD = 5.4), with the average age of the total sample not reported in nine studies. Of the 25 studies, only five had more male than female participants, with four studies not reporting the gender of the total or sub-samples. While a range of diagnoses were reported across some studies, 13 studies reported the sample to be typically-developing and five studies did not report diagnosis. Studies were conducted across nine countries, with the highest number conducted in the USA (n = 10), followed by Australia (n = 4). Additional details on participant characteristics are reported in Table 2.
Study design, methodological quality and risk of bias of studies included in the systematic review.
Most studies were randomised or pseudo-randomised control trials, with only three employing a multiple baseline design (see Table 2). The methodological quality for each study according to Kmet criteria is reported in Table 2. The average methodological quality rating across all studies was 83.4% (SD: ±8.7, range: 64–96%), indicating “strong” methodological quality. Of the studies, 17 were rated as “strong”, with all others rated to have “good” methodological quality. No study was rated to have adequate or poor methodological quality.
Shyness outcome measures.
While studies reported several outcome measures, only those relevant to shyness and/or social anxiety were the focus of this review. Across categories of self-report, parent-report, teacher-report, clinician-rating and observation measures of shyness, self- reported (n = 13) and parent-reported (n = 13) shyness outcome measures were most frequently used and clinician-rating was used least across studies (n = 7; see Table 2). Using the categories of outcome measures above, nine studies used two different types of outcome measures, seven studies used only one type of outcome measure, and nine studies used three or more types out outcome measures.
The majority of studies included an intervention that was delivered weekly (n = 15), in a child group format (n = 14), in the school setting (n = 10). Only four studies reported session durations of 40 minutes, with 14 reporting sessions for 60 minutes or longer. Intervention delivery was reported to be at least 7 weeks in 17 studies (see Table 3).
Descriptions of active intervention components reported in the included studies were reviewed and categorised. In terms of active intervention components, the studies used psychoeducation (n = 11), in-vivo exposure (n = 11), SST (n = 9), therapist modelling (n = 9), cognitive restructuring (n = 8), behaviour modification (n = 6), peer-mediation (n = 6) and video-modelling (n = 1). Across the studies, 12 used only one or two intervention components, while only five studies used a combination of 4 or more intervention components (see Table 3).
Reported treatment outcomes
Across the included studies, significant reduction was reported for anxiety (n = 13), social phobia (n = 3), and internalising behaviours (i.e., withdrawal, avoidance, and isolation; n = 8). A significant improvement was found for play skills (n = 2) and aspects of social functioning (n = 8); social competence, social skills, social interaction, social adjustment, interpersonal skills, peer victimisation, perceived social support from peers, and pro-social behaviour. Further, four studies reported treatment gains to be maintained at follow-up periods between 6 months and 5 years (see Table 3).
Effects of interventions.
Twenty of the 25 studies were included in the meta-analysis. Five could not be included in the analysis as the data required were not reported [28,31,32,34,36]. Authors were contacted to collect the required data, but no responses were received.
Overall treatment effects were calculated for shyness interventions on within-group pre-post outcome measures. Sub-group analysis was conducted to compare the effect as a function of intervention characteristics: 1) setting (i.e., clinic, home, school, online or a combination); 2) mode of delivery (i.e., group interventions, individual interventions or both); 3) intervention focus (i.e., parent focused, child focused or both); and 4) rater of outcome measure (i.e., clinician-rated, parent-rated, self-report, teacher-rated or a combination).
Between groups analysis was also conducted to compare experimental groups post-interventions scores with those of the control groups. A further 3 studies were excluded from this analysis as they did not include control groups. The following four control condition types were included: 1) waitlist control groups where participants served as an untreated comparison group who eventually went on to receive the intervention; 2) control groups that received no intervention; 3) alternative treatment controls where participants received an intervention that did not have the approach of the intervention being tested; and 4) medication control groups, where participants received medication instead of the behavioural intervention.
Overall effect of shyness interventions.
Effect sizes ranged from 0.04 to 3.18 in the within-group pre-post intervention without groups analysis, as shown in Fig 2. Of the 20 studies included 75% (n = 15) produced a large effect size and 15% (n = 3) produced a moderate effect. An effect size of < 0.2 was measured in 10% (n = 2) of the studies. The overall intervention effect was large and statistically significant (z(20) = 7.03, p < .001, Hedge’s g = 1.21, 95% CI = 0.87–1.54). The between-study heterogeneity was significant Q(19) = 137.16, p < 0.001) and 86.2% of true variability (I2) could be explained by individual study characteristics.
Effect size as a function of intervention characteristics (within-group).
Table 4 shows the effect sizes of shyness interventions grouped by delivery setting, focus of the intervention, mode of delivery, and rater of outcome measures.
Setting. Interventions that were delivered within a clinic demonstrated the largest effect size of those calculated as a function of setting (1.38), indicating a large, significant effect (z(9) = 10.50, p < .001, Hedge’s g = 1.38, 95% CI = 1.12–1.63). Interventions delivered online (z(1) = 4.36, p < .001, Hedge’s g = 1.21, 95% CI = 0.67–1.76) and those delivered in schools (z(9) = 3.91, p < .001, Hedge’s g = 1.03, 95% CI = 0.51–1.55) both produced a significant, large effect size. However, caution is needed when interpretation this results as only one study involved an online intervention. Interventions set in a combination of the home and a clinic produced the lowest effect size of all settings, showing a moderate, significant effect size (z(1) = 2.74, Hedge’s g = 0.62, 95% CI = 1.07–2.74). However this should be interpreted with caution as only one study used an intervention set in both a clinic and the home .
Focus. Interventions focused on the children alone produced the largest effect size of 1.33 of those calculated as a function of recipient of the intervention (z(13) = 5.93, p < .001, 95% CI = 0.89–1.78). Interventions that focused on both parents and children produced the lowest effect size, as demonstrated by a moderate but non-significant effect (z(3) = 1.67, Hedge’s g = 0.73, p = 0.1, 95% CI = -0.13–1.59).
Mode of delivery. Interventions that includes individual sessions, group sessions or both were all significant and large in effect. Those that utilised a combination of both individual and group sessions produced the largest effect (z(6) = 5.29, Hedge’s g = 1.6, p < .001, 95% CI = 0.88–1.5).
Rater of outcome measures. Interventions that used outcome measured rated by the children themselves, teachers, clinicians, parents or a combination of clinician and parents all produced large and significant effect sizes. Those that used measures completed by parents alone produced the largest effect size, however, this included only one study (z(1) = 5.2, Hedge’s g = 2.5, p < .001, 95% CI = 1.55–3.44). Those that used measures completed by clinicians and parents produced the lowest effect size, however, the effect size was still large and significant (z(2) = 2.44, Hedge’s g = 0.97, p < .05, 95% CI = 0.69–2.15).
Effect of shyness interventions compared with comparison groups (between-group).
As shown in Fig 3, shyness interventions for school-age children demonstrated a large, significant effect when compared to comparison groups (z(18) = 5.03, Hedge’s g = 0.82, p < .001, 95% CI = 0.5–1.14). Of the 18 studies included in the between-groups analysis, 33.3% (n = 6) produced a large effect size, 5.5% (n = 1) produced a moderate effect size, 38.8% (n = 7) produced a small effect size, and 22.2% (n = 4) produced a negligible effect size. The between-study heterogeneity was significant Q(17) = 113.84, p < 0.001) and 85.1% of true variability (I2) could be explained by individual study characteristics.
Effect size as a function of intervention characteristics (between-group).
Table 5 shows the effect sizes of shyness interventions grouped by delivery setting, focus of the intervention, mode of delivery, and rater of outcome measures when compared to control groups.
Setting. When compared to a control group, interventions delivered in a clinic produced the largest effect size of those calculated as a function of setting z(9) = 3.69, Hedge’s g = 1.05, p < .001, 95% CI = 0.5–1.61). Interventions delivered in a combination of the clinic and home, and those delivered online, produced small and non-significant effects. However, these only comprised of one study each. Interventions delivered in school produced a moderate, significant effect size (z(7) = 2.93, Hedge’s g = .76, p < .01, 95% CI = 0.25–1.27).
Focus. Interventions focusing on both children and their parents demonstrated a large but non-significant effect size when compared to control groups (z(3) = 1.54, Hedge’s g = 1.01, p = .123, 95% CI = -0.28–2.3). Those focusing on children alone demonstrated a large, significant effect size (z(12) = 3.95, Hedge’s g = .93, p < .001, 95% CI = 0.46–1.39). Interventions that focused on the parents alone produced a small but significant effect size (z(3) = 3.62, Hedge’s g = 0.49, p < .001, 95% CI = 0.22–0.75).
Mode of delivery. Interventions that used group sessions (z(13) = 4.31, Hedge’s g = .92, p < .001, 95% CI = 0.49–1.33) or a combination of individual and group sessions produced large effect sizes when compared to control groups (z(3) = 1.98, Hedge’s g = .88, p < .05, 95% CI = 0.1–1.75). Interventions using only individual sessions produced a small and non-significant effect when compared to control groups.
Rater of outcome measure. Interventions that used measures rated by parents demonstrated a large but non-significant effect size when compared to a control group, however, this included only 2 studies. Interventions that used measures rated by clinicians showed a large, significant effect size (z(9) = 3.76, Hedge’s g = .95, p < .001, 95% CI = .45–1.44).
Publication bias. The Begg and Mazumdar rank correlation procedure produced a tau of 0.588 (two-tailed), indicating there is no evidence of publication bias. This finding was supported by Duval and Tweedie’s trim-and-fill procedure using the fixed-effect model; the point estimate for the combined studies is 0.433 (95% CI: 0.319, 0.546). Using trim and fill, these values are unchanged. Under the random-effects model the point estimate for the combined studies is 0.819 (95% CI: 0.499, 1.138). Using trim and fill, these values are unchanged. Both of these procedures indicate the absence of publication bias (see Fig 4 for funnel plot).
This study systematically identified available interventions for shy children and evaluated the effectiveness of these interventions in reducing psychosocial difficulties in school. Using systematic review and meta-analysis procedures, all study designs were included when identifying the available interventions. Both RCTs and quasi-experimental studies were included in the meta-analysis to broaden the scope and examine the effectiveness of all possible intervention studies for shy children.
The systematic review revealed that 25 studies met the inclusion criteria, comprised of 24 different interventions aiming to address shyness. All the included studies and the employed interventions were directed at school children, aged between six and twelve years. School is identified as a primary setting where shyness and its associated difficulties manifest or be noticed for the first time, as it is often a child’s first social environment away from parents. School often presents many different social situations for a child to navigate, such as classroom interactions, playgrounds and social cliques. Therefore, schools are suitable contexts for delivering ‘early’ intervention.
The results of the systematic review and meta-analysis support the association between intervention and reduction in shyness for this age group. As such, school-age may be an ideal developmental and social stage in life to target shyness to lessen the impact of shyness in school-age and later in life. However, the systematic review excluded any children outside of the age range, thus the systematic review cannot confirm that interventions at younger or older age groups, such as pre-school children, adolescence or young adults, are more or less effective. However, it is possible that shyness could be identified and addressed at earlier developmental stages or need intervention later into adolescence. A longitudinal study of fifth grade boys showed that, when children had better peer relationships, their shyness was more likely to decrease or remain stable over four years . Those who were described as having poor peer relationships often increased in shyness.
Shy children may experience a wide range of difficulties in school that may impact their academic performance, social interactions and overall wellbeing . A population-based, longitudinal study of children showed from ages 1.5 to 12.5 years, parent-reported shyness increased steadily over time . Shyness that remained stable and increasing shyness also predicted poor social skills and higher levels of anxiety at the end of the follow-up . The results of the current study suggest that by promoting protective factors and introducing intervention, shyness can change as a child matures into adolescence and young adulthood, but that without such protective factors, shyness can remain a hindrance. However, how adolescents and young adults experience shyness and the required composition of active intervention ingredients to affect change in shyness in this age group are not well understood. Further research is needed into the effectiveness of interventions for shyness for younger children and for adolescents, as well as long-term impacts of interventions into adulthood.
Most studies included interventions that were delivered in a school setting. The within-group meta-analysis revealed interventions in this setting showed a large effect in reducing shyness, which is consistent with extant literature regarding shyness in school. Historically, the classroom has been the setting for implementing shyness interventions, as teachers often notice and informally attempt to address reticent behaviour . Such informal interventions often included tailoring material to accommodate a noticeably shy child, individualised support within the classroom, and using social learning strategies such as modelling and positive reinforcement [19,20,22]. Of the included interventions that were set in a school, none were set in the classroom, suggesting that extending interventions beyond the classroom can have a large impact on shyness. These school-based interventions often involved clinical methods such as social skills training, psychoeducation, and exposure. The interventions were often conducted in group sessions, based at the school, and involved activities such as play, modelling and reinforcement by the facilitator [28,29,32,34,36,43,46,47,51,52]. These methods have previously been criticised for not considering the social environment and peer interaction within which shyness manifest . However, traditionally such methods have been confined to clinic settings and clinic-based interventions demonstrated the highest effect-sizes. However, the advantage of delivering interventions in a school setting, rather than a clinic setting, is the added value of ecological validity . As such, the burden is less on school-based intervention, compared with clinic-based interventions, for treatment effects to generalise to a natural social context within which treatment strategies are applied [54,55]. The results of the current study show that, when such methods are used in a school-based setting and involve peers, the results can be effective in reducing shyness. This is consistent with recommendations by Mychailszyn, Cohen  and Crozier  that interventions should be age-appropriate, consider social development, and utilise school-wide programs that address all students, rather than targeted, clinic based interventions.
Findings from the within-group meta-analysis indicated that interventions that focused solely on the child produced the largest effect size when compared to other interventions that focused on parents alone or a combination of child and parent. Interventions focussing on both parents and children, often in the form of parent training and education, produced the lowest, non-significant effect size. This is contrary to previous recommendations that advocated for implementing interventions for shyness that involve both parents/carers as well as children themselves . Wider literature regarding interventions for children with developmental disorders, such as autism spectrum disorder, have found that involved parent training and coaching alongside interventions for children is most effective in improving language and communication outcomes, compared to sole child or parent training . This finding suggests that shyness may be unique to other conditions or disorders affecting social communication. This finding may be explained by how shyness develops. Early interactions between the child, their environment, parents and peers are believed to either promote or diminish the risk of later anxiety and shyness for the child [4,8,9]. It may be possible that a parent’s role in early development and supporting interactions between their child, environment, other adults, and peers may be more important than at an intervention level once shyness has developed. Therefore, parental involvement in shyness interventions may be more important when delivering interventions to children before they start school. The taxonomy of shyness proposes that shyness can stem from peer exclusion or different sources of fear within the child, including fear of novel social situations, fear in familiar situations and fear of perceived evaluation . Given the results of the current meta-analysis, it may be possible that such internal (fear) and external (exclusion) sources of shyness are best addressed with the children, to resolve internal fears and promote inclusion with peers.
Overall, the between-groups meta-analysis revealed that all interventions of shyness demonstrated a large, significant effect size when compared to control groups of either no intervention, treatment as usual or medication interventions. When examining this effect as a function of setting, focus, mode, and rater of outcome, the results closely mirror that of the within-groups analysis. That is, clinic-based, child-focussed, and a combination of individual and group delivered interventions produced the largest effect sizes. Within-groups results should be interpreted with caution due to the lack of control group. However, the only difference between within-groups analyses and between-groups containing a control group was that, for between-group meta-analysis, group delivered interventions were slightly higher than a combination of individual and group delivered interventions.
The findings from this study builds on the evidence for effectiveness of interventions for shyness of school-aged children, by improving their social interactions with peer and reducing reticent behaviour. However, this review found no evidence of long-term benefits of reducing later development of social anxiety disorders or long-term impacts on educational and wellbeing outcomes. Further research with longitudinal follow-up is necessary to establish the long-term effectiveness of shyness interventions.
There was variation in how shyness was defined, conceptualised, and operationalised across the included studies. Some studies required a diagnosis of social phobia for inclusion into the intervention, whereas others relied on parent or teacher report of shy behaviours. This is reflective of definitional variation in the literature regarding shyness and limits the generalisability of the results found between studies. The children included in individual studies had a range of diagnoses that may have impacted the effectiveness of the included interventions. Further research is needed to examine effects of interventions for children with and without clinical levels of social anxiety and wider diagnoses. The current review focused on school-age children aged between six and twelve years. As such, no conclusions can be drawn about the effectiveness of interventions for younger children and adolescents or the long-term impacts of interventions. When examining settings of interventions, two categories only included one study each. Therefore, the results of these categories need to be interpreted with caution. This review was unable to ascertain which individual intervention components contributed most to the effectiveness of interventions. Further research is needed to isolate the active ingredients of the interventions and determine which contributes most to the effectiveness of interventions.
Shyness impacts many school-aged children and can have lasting effects on peer interactions, wellbeing, psychosocial and academic achievement. The current study provides a comprehensive review of interventions for shyness, identifies the most commonly used strategies and intervention effectiveness. Of the 25 studies included in the review, most interventions were delivered weekly, to a group of children in a school-based setting. They employed strategies such as psychoeducation, exposure, modelling, cognitive restricting, and peer mediation to address shyness. Across all included studies, reductions were reported in anxiety, social phobia, and internalising behaviours. The meta-analysis revealed that clinic-based, child-focussed, and a combination of individual and group interventions wielded the most benefits in reducing shyness. However, school-based interventions also produced large effect-sizes and have ecological validity as an advantage. This systematic review and meta-analysis provide an evidence-based for the most effective interventions for shy children that must utilise clinical strategies, such as modelling and exposure, that should ideally be delivered in a school-based setting that facilitates interactions with peers.
The authors would like to acknowledge the contributions of Dr Bas Heijnen and Dr Sarah Wilkes-Gillan for providing research assistant support during abstract selection, data extraction and population of tables.
- 1. Crozier WR. Children’s shyness: A suitable case for treatment? Education Psychology in Practice. 2014;30(2):156–66.
- 2. Coplan RJ, Rubin KH. Social withdrawal and shyness in childhood. History, theories, definitions, and assessment. In: Rubin KH, Coplan RJ, editors. The development of shyness and social sithdrawal. New York: The Guilford Press; 2010. p. 179–212.
- 3. Coplan RJ, Rubin KH, Fox NA, Calkin SD, Steward SL. Being alone, playing alone and acting alone: Distinguishing among reticence and passive and active solitude in young children. Child Development. 1994;65(1):129–37. pmid:8131643
- 4. Gazelle H, Ladd GW. Anxious solitude and peer exclusion a diathesis stress model of internalizing tajectories in childhood. Child Development 2003;74(1):257–78. pmid:12625449
- 5. Kagan J. Temperament and the reactions to unfamiliarity. Child Development. 1997;68(1):139–43. pmid:9084130
- 6. Rimm-Kaufman SE, Kagan J. Infant predictors of kindergarten behavior: The contribution of inhibited and uninhibited temperament types. Behavioral Disorders. 2005;30(4):331–47.
- 7. Rubin KH, Coplan RJ, Bowker JC. Social withdrawal in childhood. Annual Review of Psychology. 2009;60:141–61. pmid:18851686
- 8. Gazelle H, Rubin KH. Social anxiety in childhood: Bridging developmental and clinical perspectives. New Directions for Child and Adolescent Development. 2010;2010(127):1–16. pmid:20205182
- 9. Rubin KH, Root AK, Bowker JC. Parents, peers and social withdrawal in childhood: A relationship perspective. New Directions for Child and Adolescent Development. 2010;20(127):79–94. pmid:20205181
- 10. Kalutskaya I, Archbell KA, Moritz Rudasill K, Coplan RJ. Shy children in the classroom: From research to educational practice. Translational Issues in Psychological Science. 2015;1(2):149–57.
- 11. Evans MA. Language performance, academic performance, and signs of shyness: A comprehensive review. In: Rubin KH, Coplan RJ, editors. The development of shyness and social withdrawal. New York: The Guilford Press; 2010. p. 179–212.
- 12. Jones MG, Gerig TM. Silent Sixth-Grade Students: Characteristics, Achievement, and Teacher Expectations. The Elementary School Journal. 1994;95(2):169–82.
- 13. Hanish LD, Guerra NG. Agressive victims, passive victims, and bullies: Developmental continuity or developmental change? Merill-Palmer Quarterly. 2004;50(1):17–38.
- 14. Gazelle H, Rudolph KD. Moving toward and away from the world: Social approach and avoidance trajectories in anxious solitary youth. Child Development. 2004;75(3):829–49. pmid:15144489
- 15. Henriksen RE, Murberg TA. Shyness as a Risk-Factor for Somatic Complaints Among Norwegian Adolescents. School Psychology International. 2009;30(2):148–62.
- 16. Murberg TA. Shyness Predicts depressive Symptoms Amongs Adolecents: A prospective Study. School Psychology International. 2009;30(5):507–19.
- 17. Karevold E, Ystrom E, Coplan RJ, Sanson AV, Mathiesen KS. A prospective longitudinal study of shyness from Infancy to Adolescence: Stability, Age-Related Changes, and Prediction of Socio-Emotional functioning. Journal of Abnormal Child Psychology. 2012;40(7):1167–77. pmid:22527608
- 18. Rapee RM. Temperament and the etiology of social phobia. In: Rubin KH, Coplan RJ, editors. The development of shyness and social withdrawal New York: The Guilford Press; 2010. p. 277–99.
- 19. Mjelve LH, Nyborg G, Edwards A, Crozier WR. Teacher’s understandings of shyness: Psychosocial differentiation for student inclusion. British Education Research Journal. 2019.
- 20. Coplan RJ, Hughes K, Bosacki SL, Rose-Karsnor L. Is silence golden? Elementary school teachers’ strategies and beliefs towards hypothetical shy-quiet and talkative-exuberant children. Journal of Educational Psychology. 2011;103:939–51.
- 21. Deng Q, Trainin G, Rudasill K, Kalutskaya I, Torquati J, Coplan RJ. Elementary preservice teachers’ attitudes and pedagogic strategies toward hypothetical shy, exuberant, and average children. Learning and Individual Differences. 2017;56:85–95.
- 22. Nyborg G, Mjelve LH, Edwards A, Crozier R. Teachers’ strategies for enhancing shy children’s engagement in oral activities: necessary, but insufficient? International Journal of Inclusive Education. 2020;early online:1–16.
- 23. Mychailszyn MP, Cohen JS, Edmunds M, Kendall PC. Treating social anxiety in youth. In: Rubin KH, Coplan RJ, editors. The development of shyness and social withdrawal. New York: The Guilford Press; 2010.
- 24. Liberati A, Altman DG, Tetzlaff J, Mulrow C, Gotzsche PC, Ioannidis JPA, et al. The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration. Journal of Clinical Epidemiology. 2009;62(10):e1–e34. pmid:19631507
- 25. Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement. PLoS Med. 2009;6:1–6.
- 26. Kmet LM, Lee RC, Cook LS. Standard quality assessment criteria for evaluating primary research papers from a variety of fields. Alberta, Canada: Alberta Heritage Foundation for Medical Research; 2004.
- 27. National Health and Medical Research Council. NHMRC additional levels of evidence and grades for recommendations for developers of guidelines National Health and Medical Research Council. 2009.
- 28. Griffin AA, Caldarella P, Sabey CV, Heath MA. The effects of a buddy bench on elementary students’ solitary behavior during recess. International Electronic Journal of Elementary Education. 2017.
- 29. Cook CR, Xie SR, Earl RK, Lyon AR, Dart E, Zhang Y. Evaluation of the Courage and Confidence Mentor Program as a Tier 2 Intervention for Middle School Students with Identified Internalizing Problems. School Mental Health. 2015.
- 30. Beidel DC, Turner SM, Morris TL. Behavioral treatment of childhood social phobia. J Consult Clin Psychol. 2000;68(6):1072–80. pmid:11142541
- 31. Beidel DC, Turner SM, Sallee FR, Ammerman RT, Crosby LA, Pathak S. SET-C versus fluoxetine in the treatment of childhood social phobia. J Am Acad Child Adolesc Psychiatry. 2007;46(12):1622–32. pmid:18030084
- 32. Christoff KA, Scott WON, Kelley ML, Schlundt D, Baer G, Kelly JA. Social skills and social problem-solving training for shy young adolescents. Behavior Therapy. 1985.
- 33. Chronis-Tuscano A, Rubin KH, O’Brien KA, Coplan RJ, Thomas SR, Dougherty LR, et al. Preliminary evaluation of a multimodal early intervention program for behaviorally inhibited preschoolers. Journal of Consulting and Clinical Psychology. 2015. pmid:25798728
- 34. Fiat AE, Cook CR, Zhang Y, Renshaw TL, DeCano P, Merrick JS. Mentoring to Promote Courage and Confidence Among Elementary School Students With Internalizing Problems: A Single-Case Design Pilot Study. Journal of Applied School Psychology. 2017.
- 35. Coplan RJ, Schneider BH, Matheson A, Graham A. ’Play skills’ for shy children: Development of a social skills facilitated play early intervention program for extremely inhibited preschoolers. Infant and Child Development. 2010.
- 36. Fantuzzo J, Manz P, Atkins M, Meyers R. Peer-mediated treatment of socially withdrawn maltreated preschool children: Cultivating natural community resources. Journal of Clinical Child and Adolescent Psychology. 2005. pmid:15901232
- 37. Garcia-Lopez LJ, Olivares J, Beidel D, Albano AM, Turner S, Rosa AI. Efficacy of three treatment protocols for adolescents with social anxiety disorder: A 5-year follow-up assessment. Journal of Anxiety Disorders. 2006. pmid:16464703
- 38. Hum KM, Manassis K, Lewis MD. Neurophysiological markers that predict and track treatment outcomes in childhood anxiety. Journal of Abnormal Child Psychology. 2013. pmid:23690280
- 39. Kennedy SJ, Rapee RM, Edwards SL. A selective intervention program for inhibited preschool-aged children of parents with an anxiety-disorder: Effects on current anxiety disorders and temperament. Journal of the American Academy of Child and Adolescent Psychiatry. 2009. pmid:19454916
- 40. Klein AM, Rapee RM, Hudson JL, Schniering CA, Wuthrich VM, Kangas M, et al. Interpretation modification training reduces social anxiety in clinically anxious children. Behaviour Research and Therapy. 2015. pmid:26580081
- 41. La Greca AM, Ehrenreich-May J, Mufson L, Chan S. Preventing Adolescent Social Anxiety and Depression and Reducing Peer Victimization: Intervention Development and Open Trial. Child and Youth Care Forum. 2016. pmid:27857509
- 42. Lee S. Can speaking activities of residents in a virtual world make difference to their self-expression? Educational Technology and Society. 2013.
- 43. Li Y, Coplan RJ, Wang Y, Yin J, Zhu J, Gao Z, et al. Preliminary Evaluation of a Social Skills Training and Facilitated Play Early Intervention Programme for Extremely Shy Young Children in China. Infant and Child Development. 2016.
- 44. Lowenstein LF. The treatment of extreme shyness in maladjusted childrei by implosive, counselling and conditioning approaches. Acta Psychiatrica Scandinavica. 1982. pmid:7136838
- 45. Luke F, Chan CC, Au A, Lai SMK. Adaptive parenting for alleviating young children’s shyness: A randomized controlled trial of an early intervention program. Infant and Child Development. 2017.
- 46. McKenna ÁE, Cassidy T, Giles M. Prospective evaluation of the pyramid plus psychosocial intervention for shy withdrawn children: An assessment of efficacy in 7- to 8-year-old school children in Northern Ireland. Child and Adolescent Mental Health. 2014. pmid:32878357
- 47. O’Connor EE, Cappella E, McCormick MP, McClowry SG. Enhancing the Academic Development of Shy Children: A Test of the Efficacy of INSIGHTS. 2014.
- 48. Rapee RM, Jacobs D. The reduction of temperamental risk for anxiety in withdrawn preschoolers: A pilot study. Behavioural and Cognitive Psychotherapy. 2002.
- 49. Rapee RM, Kennedy S, Ingram M, Edwards S, Sweeney L. Prevention and early intervention of anxiety disorders in inhibited preschool children. Journal of Consulting and Clinical Psychology. 2005. pmid:15982146
- 50. Sang H, Tan D. Internalizing behavior disorders symptoms reduction by a social skills training program among chinese students: A randomized controlled trial. NeuroQuantology. 2018.
- 51. Umeh CS. ASSESSMENT AND MANAGEMENT OF SHYNESS USING GROUP COGNITIVE BEHAVIOURAL THERAPY AMONG SELECTED NIGERIAN ADOLESCENTS. 2013.
- 52. Rawdon C, Murphy D, Motyer G, Munafo MR, Penton-Voak I, Fitzgerald A. An investigation of emotion recognition training to reduce symptoms of social anxiety in adolescence. Psychiatry Research. 2018;263:257–67. pmid:29602534
- 53. Chen X, Fu R, Li D, Liu J. Developmental trajectories of shyness-sensitivity from middle childhood to early adolescence in China: Contributions of peer preference and mutual friendship. Journal of Abnormal Child Psychology. 2019;47(7):1197–209. pmid:30637554
- 54. Parsons L, Cordier R, Munro N, Joosten A. A Play-Based, Peer-Mediated Pragmatic Language Intervention for School-Aged Children on the Autism Spectrum: Predicting Who Benefits Most. Journal of Autism and Developmental Disorders 2019;49:4219–31. pmid:31292899
- 55. Hodges A, Joosten A, Bourke-Taylor H, Cordier R. School participation: The shared perspectives of parents and educators of primary school students on the autism spectrum. Research in Developmental Disabilities. 2020;97(103550):1–12. pmid:31881439
- 56. Parsons L, Cordier R, Munro N, Joosten A, Speyer R. A systematic review of pragmatic language interventions for children with autism spectrum disorder. PLoS ONE. 2017;12(4):e0172242. pmid:28426832