The long-standing rivalry between siblings has taken a new turn as recent research shines a spotlight on a surprising “villain” within Thai and global families—the older brother. A large-scale study from the University of Warwick suggests that birth order does matter, with older brothers more likely to become the family aggressors, especially when it comes to bullying their younger siblings. This revelation not only disrupts traditional assumptions about sibling dynamics but also raises important questions about long-term well-being, family culture, and childhood development in Thailand.
Childhood sibling rivalry is a near-universal phenomenon across cultures. In Thai homes, as elsewhere, the roles of big brother, younger sister, and middle child have been the subject of jokes, legends, and sometimes deep wounds. Many Thais recall the contrasting parental expectations for eldest children—responsibility, maturity, guidance—versus the supposed indulgence granted to the youngest. However, according to this recently publicized research, the eldest brother’s role may carry a darker side, as they are disproportionately the instigators of sibling bullying. For Thai readers, whose cultural norms emphasize harmony within the home and filial respect, these findings cut to the core of family relationships.
The Warwick study, highlighted recently by publications such as YourTango and corroborated by additional cohort studies, tracked the lives of nearly 7,000 children until age 12, mapping the ebb and flow of dominance, rivalry, and affection between siblings. Strikingly, their results found that in families with siblings, older brothers were most likely to be the aggressors. Boys made up 69% of siblings who engaged in bullying behavior, with older siblings in larger families being the most frequent offenders. The study described sibling bullying as often “an evolutionary-driven strategy towards maintaining or achieving social dominance, and older siblings are at particular risk of initiating sibling bullying” (YourTango).
Family therapists cited in the original report offered insights that resonate with Thai family structures. Parental approval—such as being praised or compared favorably to another sibling—heightens rivalry and the potential for aggression. According to a family therapist interviewed, “Children are very sensitive to comparisons, and it can increase the rivalry between siblings.” In a Thai context, where public and private expressions of favor from elders can carry profound psychological consequences, such findings fit into a broader narrative about the lasting effects of parental expectations (MSN Parenting).
The driving motivations for such behavior are not isolated to individual character but appear rooted in the shifting tides of parental attention. The oldest child, often accustomed to exclusive care before the arrival of younger siblings, can experience jealousy and feelings of inadequacy as new children enter the family. This psychological struggle may lead them to exert control or dominance over their younger siblings, primarily through bullying and negative attention-seeking behaviors.
Dr. Karen Gail Lewis, a prominent voice in family therapy, explained, “The emotions and attitudes one holds toward a sibling during early childhood can become deeply ingrained, resulting in a lasting impression… These perceptions, whether positive or negative, can become ‘frozen’ and remain unchanged for many years to come.” This ‘frozen’ family dynamic is particularly important for Thai families, who often put great emphasis on the unchanging hierarchy and harmony among siblings.
Further emphasizing the broader consequences, a longitudinal study directly links sibling bullying to higher rates of risk behaviors later in life. Siblings who bully may carry those tendencies forward, manifesting in aggression, substance abuse, or even conflict with the law in adulthood (PubMed: Sibling bullying at 12 years and high-risk behavior in early adulthood). This not only affects the individual but can disrupt the entire family system, burdening Thai families already striving to navigate rapid societal and economic change.
Notably, family structure and parental relationships also play a decisive role. Where parents’ marriages were characterized by happiness and low conflict, healthier sibling relationships flourished. In households with higher parental tension, however, sibling bullying—particularly by older brothers—was more severe, compounding the negative emotional climate for all children involved (MedicalXpress).
These findings are hardly academic for the average Thai household. In a society where the eldest son’s behavior can carry cultural weight—from taking on family business responsibilities to caring for aging parents—the idea that this same son may be the hidden source of emotional distress for siblings challenges deep-seated values. It also reframes current mental health and educational interventions. Mental health professionals in Thailand have increasingly recognized sibling bullying as an under-addressed issue, closely linked to both school bullying and later-life trauma (MSN Lifestyle).
Thailand’s unique cultural perspectives on family harmony, social status within the household, and respect for elders may both exacerbate and conceal these issues. Siblings, especially younger sisters, might feel unable to voice their experiences due to respect for hierarchy. Likewise, Thai parental norms of comparison and high expectations may unintentionally intensify rivalry. Psychologists interviewed in related studies urge parents to avoid direct comparisons and instead foster individual recognition and affection for each child.
This emerging body of research compels parents, educators, and policymakers in Thailand to reconsider not just their understanding of sibling behavior, but the kinds of interventions that are truly needed. Experts recommend several practical steps. First, parents are advised to recognize early signs of sibling aggression—verbal teasing, exclusion, or physical intimidation—and to intervene promptly. Family counselors suggest open dialogue, family meetings, and setting clear rules about respect and conflict resolution. Schools can play a supplementary role by incorporating family dynamics into anti-bullying programs and creating safe spaces for students to discuss home life challenges confidentially.
Furthermore, mental health professionals in Thailand suggest culturally sensitive counseling that respects family hierarchies while prioritizing child welfare—addressing bullying without causing undue shame or loss of face. As many Thais turn to Buddhist teachings of compassion, mindfulness strategies may also be blended with modern psychology to address underlying tensions.
Looking ahead, the implications of these studies are profound. As birth rates decline and family sizes shrink in Thailand, the spotlight on sibling dynamics will likely intensify. Fewer children may mean greater parental scrutiny for each, potentially exacerbating comparisons and rivalries. On the other hand, smaller families could allow for more individualized parenting and closer sibling bonds if handled with care.
For parents and educators striving to nurture better futures for young Thais, the message is clear: open, non-judgmental communication and equal affection are key. Refrain from making comparisons, listen to each child’s needs, and handle conflicts as teaching moments—not opportunities for punishment or shame. By doing so, families can transform sibling rivalry from a source of pain into a foundation of lifelong support. And to the country’s eldest brothers—perhaps it’s time for a little more empathy, and a little less roughhousing.
For further reading on sibling bullying, visit resources such as the University of Bristol’s study on sibling bullying, PubMed research summaries, and reviews from family therapists in international media (YourTango). Thai-specific mental health resources can also be found through government health websites and local counseling organizations.