For example, when researchers have tracked the development of children with siblings, they've found a telling pattern: Having an older sibling facilitates the development of theory of mind. (parentingscience.com)
Move This World is rooted in theories of positive psychology and creative expression. (movethisworld.com)
I can understand the conspiracy theory in your comment, because I thought the same thing... But 3 years ago!? (justarsenal.com)