The bilingual advantage in cognitive function has been demonstrated especially in children and older adults, while the advantage in young adults has been rather variable. Suggestions for this finding may be that young adults are at their peak cognitive function, so it may be difficult to show any bilingual advantages beyond that peak level, especially in simple executive function tasks. It is thought that the benefits may be particularly beneficial to individuals at points in their lives when they are more vulnerable, for example in early development and later in life, when ordinary cognitive processes decline.