Historically, bilinguals were regarded as having a relatively lower IQ than monolinguals. The idea of ‘intelligence as a singular fixed construct has been challenged by more recent theories of multiple intelligences, emotional intelligence and mindsets.Research on the relationship between intelligence and bilingualism has moved from a period of investigating ‘detrimental effects' to a current focus on the additive effects given by bilingualism. The ownership of two languages does not interfere with efficient thinking. On the contrary bilinguals who have two well-developed languages tend to share cognitive advantages.