Middle child is often harder to treat kids

One study showed that most of the children were stubborn, more adventurous and independent than their older siblings.

Photo: Telegraph.

Psychologists from the University of Pennsylvania, University of Hawaii and Purdue University (USA) conducted interviews with 364 children who were the second child aged 7-19 and their parents to understand their personality. They also took saliva samples from the study subjects to measure testosterone levels (male sex hormones) and asked them to record their activity outside the school.

The results of interviews and children's diaries show that most of the children born afterwards appear to be more adventurous, stubborn and independent in their thinking when they reach adulthood. Meanwhile the character of the elders has hardly changed over time.

Some previous studies also showed that the majority of the first children listened to their parents, while the second one tended to argue more.

The research of the three universities also reveals some other interesting things. For example, the second girls will become more feminine when they become girls if they often play with girls and the second boy will become more masculine if they play with their peers. However, having a close girlfriend brings benefits for both boys and girls. Specifically, those who have close girlfriends are more independent in their thinking. In addition, children with high levels of testosterone in their teens are rarely affected by the external environment during personality development. For example, they have not neglected learning whether to play with those who like you lethargic.