please read the following paragraph, which is extracted from an essay" The message behind the smile"
The Japanese, too, are a rule unto themselves when it comes to facial expressions. Under traditional Japanese codes of behaviour, negative emotions such as anger, sadness, and disgust should not be shown openly; as a result, people may end up giving a broad smile instead.
I suspect the word "are" should be " have", but I am not sure since the TEXTBOOK was printed like this.
please help me. thanks.
The book is right- it's an expression meaning that they do things their way.