Americans, someone is perceived as being highly
credible if he/she is articulate and outspoken.
Thais/Japanese, a person who is quiet and spends more time listening than speaking is more credible because they regard constant talking as a sign of shallowness.
Among Americans/Westerners, credible people seem direct, rational, decisive, and confident.
Among the Thais/Japanese, credible people are perceived as being indirect, sympathetic, prudent, flexible, and humble.