From celebrity duos like Mary-Kate and Ashley Olsen to sports legends like Serena and Venus Williams, twins often capture public fascination. Their shared bond and individual successes spark curiosity about what shapes twin relationships behind the scenes. But what happens when one twin consistently takes the lead? New research from the Hebrew University of Jerusalem and The Academic College of Tel-Aviv–Jaffa dives into the complexities of twin dynamics, revealing surprising insights about how dominance roles form and persist.

 

Exploring the Roots of Family Dynamics
The research, led by Prof. Ariel Knafo-Noam and Dr. Yonat Rum from the Hebrew University of Jerusalem, along with Dr. Hila Segal and Adi Barkan from The Academic College of Tel-Aviv–Jaffa, surveyed over 1,500 parents of twins aged 3 to 9. The study examined how developmental differences between twins influence family roles, particularly when one twin has a developmental condition like speech or motor delays.

 

What the Researchers Found
The study revealed that parents often viewed the typically developing twin as the more dominant sibling, even when the less developed twin’s condition improved over time. In families where both twins had the same developmental status, whether typical or delayed, no clear dominance pattern emerged. The research suggests that dominance dynamics are driven not just by developmental differences but also by how parents perceive and compare their twins.

 

Why Do These Roles Persist?
The researchers found that parents naturally compare their twins, a tendency known as the “contrast effect.” This means that even small differences between twins can be magnified, locking each child into specific roles — such as the “leader” and the “follower.” These roles can persist long after the developmental gap closes, shaping how twins relate to each other into adulthood.

 

How Genetics Play a Role
The study also examined the impact of genetics. Identical twins, who share nearly identical genes, were more likely to have balanced relationships than fraternal twins. This finding suggests that shared genetic traits might reduce dominance imbalances, possibly because identical twins are more similar in abilities and temperaments.

 

Breaking the Cycle: What Parents Can Do
Since early dominance roles can be hard to break, the researchers recommend these strategies for parents:

• Expand Social Circles: Encourage twins to build friendships outside the family.
• Celebrate Individual Strengths: Focus on each child’s unique talents.
• Create Leadership Moments: Let the less dominant twin take the lead in specific tasks or activities.

 

Why Understanding Twin Dynamics Matters
By understanding how family dynamics develop, parents and educators can create healthier environments that help both twins grow socially and emotionally. Addressing these dynamics early on can prevent long-term imbalances that affect self-esteem and sibling relationships.

The study, titled "You and Me: Parental Perceptions on Asymmetry in Twins' Development and Their Dominance Relationship Dynamics," is available in Family Relations. Learn more about the research here.

 

Researchers:

Hila Segal, School of Behavioral Science, The Academic College of Tel-Aviv—Jaffa, Tel Aviv, Israel

Yonat Rum, School of Education, The Hebrew University of Jerusalem, Israel

Ariel Knafo-Noam, Department of Psychology, The Hebrew University of Jerusalem, Israel

 

The Hebrew University of Jerusalem is Israel’s premier academic and research institution. With over 23,000 students from 90 countries, it is a hub for advancing scientific knowledge and holds a significant role in Israel’s civilian scientific research output, accounting for nearly 40% of it and has registered over 11,000 patents. The University’s faculty and alumni have earned eight Nobel Prizes, two Turing Awards a Fields Medal, underscoring their contributions to ground-breaking discoveries. In the global arena, the Hebrew University ranks 81st according to the Shanghai Ranking. To learn more about the University’s academic programs, research initiatives, and achievements, visit the official website at http://new.huji.ac.il/en