Differential solicitude of social support in different types of adult sibling relationships

The sibling relationship is one of the longest relationships in people's lives, and it is one of the most diverse as it occurs in many different forms. The current investigation seeks to identify differences in the amount of social support received in adult sibling relationships. The sample consisted of 411 participants in 6 different types of sibling relationships: identical twins, fraternal twins, full biological siblings, half-biological siblings, stepsiblings, and adopted siblings. Employing of ideas of discriminative parental solicitude, we developed a hypothesis about which types of siblings receive the most social support from their siblings. The basic prediction was that siblings who are more genetically related to one another receive more social support than siblings who are less genetically related. Results supported these predictions, even when social and relational explanations were controlled.