EF is an umbrella term for high level cognitive skills necessary for goal directed behavior, working memory, cognitive flexibility,problem solving etc. In the current context we specifically refer to the proficiency for problem solving and cognitive flexibility. An ample number of studies have marked the age of 12 as a period of significant improvements in some aspects of EF, such as working memory, planning, and problem-solving skills, while other aspects reached adult levels of performance only later in adolescence.