In this study, social functioning refers to how well autistic children communicate, interact, and build relationships with others.
Autistic children often face challenges in understanding social cues, initiating or maintaining conversations, and forming peer connections.
These difficulties can impact daily life, making it important to explore factors—like sibling relationships—that might support their social development.
Rum, Y., Dolev, A., Reichmann, O., Zachor, D. A., Avni, E., Ilan, M., Meiri, G., & Koller, J. (2025). The older sibling effect: Comparing social functioning outcomes for autistic children with typically developing siblings, no siblings, and autistic siblings. Frontiers in Psychology, 16, 1568110. https://doi.org/10.3389/fpsyg.2025.1568110
Key Points
- Autistic children with older typically developing (TD) siblings showed significantly better social functioning than those with no siblings.
- Autistic children with older autistic siblings demonstrated an “intermediate” level of social functioning—better than those with no siblings, but not significantly different.
- There was no significant difference in social functioning between children with older TD siblings and those with older autistic siblings.
- Parent-reported data did not replicate the findings from clinician assessments, possibly due to contrast effects or measurement differences.
- The study supports the value of sibling relationships—whether the sibling is autistic or TD—in contributing to social development in autistic children.
Rationale
Sibling relationships are crucial developmental contexts, particularly for social learning.
Previous studies found that autistic children with older TD siblings show better social functioning, likely due to modeling and interaction opportunities.
However, it is unclear how older autistic siblings affect younger autistic siblings. The “Double Empathy Problem” framework suggests that autistic-autistic dyads may foster mutual understanding and communication.
Given the growing number of families with multiple autistic children, the current study fills a gap in empirical knowledge by comparing autistic children’s social functioning across sibling group types.
Understanding whether autistic siblings provide support, hindrance, or something in between will refine developmental and clinical approaches.
Method
Secondary analysis of data from 2,039 autistic children was conducted using a matched design.
The final sample included 87 children in three matched groups: no siblings, older TD siblings, and older autistic siblings.
Groups were matched for age, sex, and cognitive scores. Social functioning was assessed using ADOS-2 and parent-report measures (ABAS/VABS).
Procedure
Study design:
Retrospective matched design using data from a national database in Israel.
Steps:
- Screened a cohort of 2,039 children.
- Applied exclusion criteria (e.g., non-Hebrew speakers, missing data).
- Identified and matched 29 triads (87 children total) across three groups.
- Conducted diagnostic assessments (ADOS-2, DSM-5 criteria).
- Analyzed social functioning scores.
- Conducted exploratory analyses with ABAS/VABS parent-report data.
Sample
- N = 87 (29 per group: No-Sib, Older-TD-Sib, Older-Autistic-Sib).
- Age range: 3–14 years (M = 5.51, SD = 2.45).
- Gender: 69% male, 31% female.
- All participants were Hebrew-speaking Israeli children.
Measures
- ADOS-2 Social Affect (SA): A clinician-administered semi-structured assessment of social functioning. Lower scores indicate better functioning.
- ABAS-3: Parent-report tool measuring adaptive functioning; includes a social functioning subdomain.
- VABS-3: Parent-report tool assessing adaptive behaviors including socialization; used in some centers due to variation.
Statistical Measures
- Repeated measures ANOVA for group comparisons.
- Paired t-tests with Bonferroni corrections.
- Bayesian ANOVA and Bayesian t-tests to evaluate strength of evidence.
- Mixed-effects models used for incomplete ABAS/VABS data.
Results
Hypothesis 1: Children with older TD siblings will show better social functioning than those with no siblings.
- Supported: Significant difference (p = .007, d = 0.62).
Hypothesis 2: Children with older autistic siblings will show either a negative or positive difference compared to those with no siblings or TD siblings.
- Partially supported: No significant difference after correction, but effect size indicated a positive trend (p = .082, d = 0.40).
Hypothesis 3: Older autistic siblings would lead to poorer outcomes than older TD siblings.
- Not supported: No significant difference (p = .647, d = −0.13).
Parent-report analysis: No significant group differences; possible small-to-moderate effects not detected due to sample size and missing data.
Insight
This study reveals that older autistic siblings may offer social interaction benefits similar to older TD siblings, potentially via shared neurotype understanding.
These findings challenge assumptions that autistic siblings provide poorer social models. They highlight the potential for positive developmental outcomes through sibling companionship regardless of diagnosis.
Further research should examine the quality of sibling interaction, including warmth, imitation, and play dynamics.
Exploring parental experience and family adaptations after raising an autistic child could clarify mediating factors.
Implications
Practitioners should consider incorporating sibling interactions—whether with TD or autistic siblings—into social skills training or family-based therapies.
Programs could include structured sibling activities to foster communication and joint play.
Policymakers and clinicians should also consider how family dynamics and sibling relationships support social development.
Attention to differences in clinician vs. parent assessments is also necessary for comprehensive evaluations.
Strengths
This study had several methodological strengths, including:
- Novel focus on autistic sibling dyads.
- Matched design controlled for age, sex, and cognition.
- Use of clinician-administered and parent-report measures.
- Replication of earlier findings with older TD siblings.
- Consideration of both behavioral and theoretical frameworks.
Limitations
This study also had several limitations, including:
- Small sample size limits generalizability and power.
- Missing parent-report data reduced statistical robustness.
- No data on sibling relationship quality or parenting practices.
- Findings may not apply to younger siblings of autistic children.
- Sociodemographic and intervention history data were unavailable.
Socratic Questions
- What mechanisms might explain the positive impact of older autistic siblings on social functioning?
- Could shared neurotype communication styles enhance sibling interaction in autistic dyads?
- How might parental expectations or experience influence children’s social development?
- Are standardized clinical assessments more objective than parent reports—or do they capture different realities?
- What would a future observational study of sibling interactions reveal about modeling and imitation?
- Should interventions for autistic children incorporate sibling dynamics as a core element?
- Could contrast effects in parent reports mask real improvements in social functioning?
- How might the findings differ if the sample included younger siblings or mixed sibling pairs?
- How do we balance measurement tools to reflect both structured observations and everyday social behavior?
- What ethical considerations should guide the study of family dynamics in autism research?
