When asked to think about how the world would be different if people didn't have thumbs, the younger children suggested very concrete changes, such as you could no longer give a "thumbs up" signal. But the adolescent demonstrated his ability to think abstractly by suggesting that this change in the hand would:

change the whole world

Explanation: The difference in thought of the young child and the adolescent varies in the sense that the adolescent could reason and form imaginary thought about something which isn't actually present or available by focusing on the deeper content of an idea in other to get a broader and deeper sense of the concept rather than the literal or concrete thinking exhibited by the younger child which involves assigning meaning or giving interpretation just as it has been heard, seen or felt. Concrete thinking are ordinary and often superficial as opposed to abstract which digs deeper into the meaning, different possible present and future implication of actions or decisions. When the thumb is absent, according to an abstract thinker, a lot in the sword would actually change.