The development of social value orientation: Attachment styles, number of siblings, age, and a comparison of measures

Nearly 25 years ago, four studies examined the development of social value orientation (SVO) and uncovered that SVO was related to specific and general adult attachment, the number of siblings, and age. However, some of these findings have been challenged by two recent replication studies. The present (pre-registered) research extends these replication studies and the original research by using multiple measurements of both SVO and adult attachment on two large samples that allowed us to detect small effect sizes. With online samples (N = 1446 and 2644) from MTurk and Prolific, we replicated earlier findings that prosociality was associated with a greater level of secure attachment and a lower level of avoidant attachment. Moreover, prosociality was positively related to the number of siblings, especially sisters, as discovered by Study 3 of the original study. However, we failed to replicate the significant relation between SVO and age. Generally, we conclude that prosocial orientation is associated—even if modestly—with secure and avoidant attachment and the number of siblings, but the link with age is a question open to future investigation.