When two dependent variables are correlated like this, it could mean that both variables are reflective of the same basic underlying psychological process. This is the position taken by Relational Frame Theory. According to RFT, deriving relations among events is the core of human language and cognition. What we learn about how humans derive stimulus relations may tell us a great deal about how humans are able to acquire and use language. This represents the basic theoretical and empirical strategy of RFT.