mental age
noun [ C usually singular ] uk/ˌmen.təl ˈeɪdʒ/ us/ˌmen.t̬əl ˈeɪdʒ/
智力年龄；心理年龄
A person's mental age is a measurement of their ability to think when compared to the average person's ability at that age.
Although Andrew is 25, he has a mental age of six. 虽然安德鲁已经25岁了，但智力年龄只有6岁。