Quote from : Cultures and Organizations: Software of the Mind - Intercultural Cooperation and Its Importance for Survival Book

In most collectivist cultures, direct confrontation of another person is considered rude and undesirable. The word is seldom used, because saying “no” is a confrontation; “you may be right” and “we will think about it” are examples of polite ways of turning down a request. In the same vein, the word yes should not necessarily be inferred as an approval, since it is used to maintain the line of communication: “yes, I heard you” is the meaning it has in Japan.