Summary: A new study reveals that developmental differences strongly influence dominance roles in twin relationships, with typically developing twins perceived as dominant over their nontypically developing siblings. This dominance imbalance persists throughout childhood, even if developmental challenges improve.
Genetic similarity also impacts dynamics, as monozygotic twins exhibit more symmetrical relationships than dizygotic twins. Parental perceptions play a critical role, often reinforcing dominance roles through biases that exaggerate differences, emphasizing the need for strategies to foster balanced relationships.
Key Facts
- Developmental Impact: Typically developing twins are consistently seen as dominant when paired with nontypically developing siblings.
- Genetic Influence: Monozygotic twins show more balanced dynamics compared to dizygotic twins.
- Parental Role: Parental biases, such as the “contrast effect,” reinforce dominance patterns in twins.
Source: Hebrew University of Jerusalem
A study conducted by Prof. Ariel Knafo-Noam and Dr. Yonat Rum from the Hebrew University of Jerusalem, alongside Dr. Hila Segal and Adi Barkan from The Academic College of Tel-Aviv–Jaffa, sheds light on how developmental differences influence the dynamics of dominance in twin relationships throughout childhood.
Twins, unlike singletons, share the same age and often a similar environment, creating unique relational dynamics where traditional factors like birth order play no role.
This study, published in Family Relations, explored how differences in developmental conditions between twins, particularly when one child has a developmental condition and the other does not, affect their dominance dynamics over time.
The research surveyed over 1,500 parents of monozygotic and dizygotic twins aged 3 to 9. It found that when one twin was typically developing and the other had a developmental condition, parents consistently perceived the typically developing twin as the dominant sibling.
This dominance imbalance was stable throughout childhood, even in cases where the developmental challenges of the nontypically developing twin were resolved. In twin pairs where both siblings shared the same developmental condition, whether typical or nontypical, no significant differences in dominance were reported.
These findings suggest that it is not the developmental condition itself, but the asymmetry in abilities between the twins, that drives dominance imbalances.
Parental perceptions played a significant role in shaping these dynamics. The study relied on previous work showing that parents often emphasize differences between twins through what is termed the “contrast effect,” a bias that exaggerates perceived differences.
This parental tendency can reinforce dominance roles, affecting how twins interact with one another and shaping their long-term relational dynamics.
The findings align with family systems theory, which posits that families function as interconnected units where the behavior and roles of one member influence the others.
In this context, parental perceptions and behaviors may inadvertently solidify certain roles, such as “dominant” or “submissive,” in twins’ relationships.
Interestingly, genetic similarity also influenced dominance patterns. Monozygotic twins, who share nearly identical genetic material, were more likely to display symmetrical dominance relationships compared to dizygotic twins, even in cases where developmental conditions differed.
This suggests that genetic factors and personality traits may play a role in shaping dominance behaviors and creating more balanced relationships in identical twin pairs.
The study also revealed that dominance roles established early in life tend to persist, even when the developmental condition of a nontypically developing twin improves.
This persistence can be understood through role theory, which explains how family roles, once established, become ingrained through both behavior and parental reinforcement. To mitigate the effects of entrenched dominance roles, parents are encouraged to create opportunities for more balanced dynamics.
Encouraging twins to engage in relationships outside their twinship, fostering individuality, and providing avenues for the less dominant twin to assert themselves in specific domains can help reduce the long-term impact of these dynamics.
This research offers a nuanced understanding of how developmental differences shape twin relationships and underscores the importance of parental awareness in navigating these dynamics.
By addressing these patterns early, parents and caregivers can foster healthier, more balanced sibling relationships that benefit both twins’ social and emotional development.
About this genetics, personality, and neurodevelopment research news
Author: Yarden Mills
Source: Hebrew University of Jerusalem
Contact: Yarden Mills – Hebrew University of Jerusalem
Image: The image is credited to Neuroscience News
Original Research: Open access.
““You and me”: Parental perceptions on asymmetry in twins’ development and their dominance relationship dynamics” by Ariel Knafo-Noam et al. Family Relations
Abstract
“You and me”: Parental perceptions on asymmetry in twins’ development and their dominance relationship dynamics
Objective
This study investigated the role of nontypical development in the relative dominance in twins’ relationships throughout childhood. Background Dominance dynamics, affecting siblings’ well‐being, are different in twins than in singletons for whom age and development often dictate sibling hierarchy.
These dynamics in twins, who share similar ages and developmental contexts, remain underexplored and demand further understanding.
Method
A longitudinal study surveyed 1,547 mothers and 536 fathers of 322 monozygotic (sharing nearly 100% genes) and 1,199 dizygotic (sharing 50% genetic variance) twin pairs, aged 3 to 8–9. Both parents reported on the twins’ relationships. Mothers reported whether either twin had a developmental condition.
Results
No dominance difference was found in similar developmental conditions dyads, whether both twins had typical or nontypical development. However, in dyads where twins differed in the developmental condition, nontypically developing twins were less dominant than their typically developing cotwins. This dominance imbalance persisted throughout childhood, even if initial developmental issues were resolved.
Conclusion
From parents’ perspectives, nontypical development does not, in itself, prevent children from demonstrating dominance behaviors in twinship, but it is more likely that the asymmetry in developmental conditions is associated with the relationship between the twins.
Implications and Recommendations According to parents’ perceptions, twins with nontypical development might experience imbalances in their relationship throughout childhood when their co‐twin is a typically developing child. However, demonstrating dominance might be possible for them in other contexts.
Understanding these dominance dynamics is vital for caregivers, informing tailored parenting strategies and interventions to support the well‐being of children.
