Teenage friendship may not last forever if the traits of friends are not similar, says a new study.
The study says that differences can lead to conflict in friendships formed during teenage years and may eventually cause early dissolution of friendship.
"Adolescents are most likely to enjoy successful, long-term friendships with those who share similar traits," says Brett Laursen, professor at Florida Atlantic University in the US.
The study looks at 410 adolescents involved in 573 friendships that originated in the seventh grade. Researchers follow the participants from grade seven through grade 12.
Fewer than one fourth of the friendships that start in the seventh grade continue across the next school year, and fewer than one in 10 friendships that start in the seventh grade survive the transition from middle school to high school.
Only one percent of friendships that begin in the seventh grade continue to the 12th grade. The strongest predictors of friendship dissolution are differences in sex, differences in the degree to which children are liked by other children, differences in physical aggression and differences in school competence.
By far the strongest predictor is difference in sex; other-sex friendships are almost four times more likely to dissolve than same-sex friendships, the findings show.
The next strongest predictor is difference in physical aggression, followed by differences in school competence, and differences in being liked by other children.
Rates of dissolution increase by 25% to 43% for each unit of difference on these variables, according to the results published in the journal Psychological Science.
"We knew from previous studies that children prefer similar others as friends," says Laursen.
"Now we know why differences are bad for friendships. It causes conflict, interferes with cooperative activities and shared pleasures. It creates circumstances where one friend bears more costs, such as the friend who is less aggressive or gets more benefits like a friend who has lower social status than the other," Laursen adds.