The above is a joke.
In fact, few people put their hands on their chins while thinking.
This misunderstanding mainly comes from the famous sculpture The Thinker.
The statue of "Thinker" created a powerful laborer.
The giant bent down, bent his knees, cupped his chin in his right hand and silently watched the tragedy below.
This has caused everyone to subconsciously think that most people will do this when thinking, so they will subconsciously touch their chin when thinking.