The possibility that bilingualism could impact cognitive ability began with research with children [1], but others reported that bilingual middle-aged and older adults outperformed their counterparts on a Simon task commonly used to investigate attention and perception [2]. These results suggested there could be broader implications for bilingualism than had been previously considered. The paper was followed by many replication attempts comparing monolingual and bilingual adults performing executive function tasks, but no simple relation between bilingualism and performance was found [3].
