Informality
Americans treat each other in an informal manner, even if there are big differences in age or social position. It is also common for employees or students to act casually with their professors and advisors; however, this is not a sign of disrespect.
First (given) names are often used in the U.S. You can usually use first (given) names without a title if the other person is of approximately the same age and status. You might call somebody by their title and last (family) name (“Dr. Smith” for example) and they may reply, “Just call me John,” which is their first (given) name. You should not add any title or prefix to their first name (do not call them “Mr. John,” for example).
Calling somebody by only his or her first name is usually a sign of friendliness or acceptance. Do not be shy to ask people how they would like you to call them and to say what you would like them to call you.
- A woman older than yourself can be addressed as Miss or Mrs. (pronounced “missus”), depending on whether she is married. Ms. (pronounced “mizz”) can be used for either a single or married woman unless she has a title such as doctor (Dr.) professor (Prof.) or Dean.
- An older man may be addressed as “Sir” if you don't know his name. If older people want you to call them by their first name, they will probably ask you to do so.
Clothing
Informality also extends in the way people dress and communicate with each other. Look at other people where you work as an indication of how you should dress.
- Many research laboratories at the hospitals have an informal look and do not require suits or other formal clothing.
- It is quite acceptable for women to wear very little clothing outdoors in the summer; this is not an indication of loose morals.