Sibling attachment is further accentuated in the absence of a primary caregiver, when the younger sibling must rely on the older one for security and support.
Even as siblings age and develop, there is considerable stability in their relationships from infancy through middle childhood, during which positive and negative interactions remain constant in frequency.
At the same time, the older sibling is also available to answer questions and discuss topics that the younger sibling may not feel comfortable bringing up to a parent.
However, this effect varies based on sex of siblings.
In industrialized cultures, sibling relationships are typically discretionary in nature.
People are encouraged to stay in contact and cooperate with their brothers and sisters, but this is not an obligation.
In India, the brother-sister sibling relationship is so cherished that a festival is held in observance called Rakhi.
Despite these factors, siblings often maintain a relationship through adulthood and even old age.
This trend may be the result of an increased emphasis on peer relationships during adolescence.
Often, adolescents from the same family adopt differing lifestyles which further contributes to emotional distance between one another.
Furthermore, both relationships are often egalitarian in nature, although unlike sibling relationships, friendships are voluntary.
The specific roles of each relationship also differ, especially later in life.