Generalizations are piece of advice and recommendation on how to behave in different countries in certain situations. Generalizations are kind of empirical evidence because they are not only just general statements about how things in a certain culture are, but you can observe them in real life as well. Generalizations do not evaluate people, but they are only descriptive. Also, generalizations can be first-hand knowledge and don’t necessarily need to be from second-hand sources.
Examples for generalizations would be: In China, harmony and building relationships are more important than productive business meetings or If your are invited to a dinner in France, you are expected to be 15 minutes late.
In contrast to generalizations, stereotypes are common and clichéd beliefs about groups of people and their behaviour, character, competence, likes and dislikes. Stereotypes can be positive or negative. The latter are so-called prejudices, where individual persons are judged on the basis of characteristics of a specific group, without taking into consideration additional information or considering this person to be an exception from this rule. Stereotypes come from second-hand sources and are never from personal experience. They typically cloud your perception. They are not descriptive, but always evaluate people. Most stereotypes are based on over-generalizations, meaning that they still have a kernel of truth, but are extremely oversimplified. People use stereotypes to help them make sense of what is happening around them and to guide their actions. Additionally, especially with prejudices, they make you feel better about your own group or country. There also can be stereotypes within a country.
Examples for stereotypes could be: All Asians look the same or Russians drink vodka all the time.

A self-fulfilling prophecy is a phenomenon that happens if you treat people as you expect them to be and only because of your behaviour the people begin to behave just like you expected them to be. The interesting thing is, that these people would have reacted differently if you wouldn’t have approached them with your stereotypes and prejudices in mind. Therefore, the concepts of stereotypes and self-fulfilling prophecies are closely related. Stereotypes can change the way you behave and think and with your actions you shape the reactions of the people you interact with.
If you for example think that your new neighbour, who moved into the house next to you last week, is grumpy and unfriendly, you start to behave as if he actually was like this. Even if in reality he just had a lot to do with packing up things or maybe was stressed or not in a good mood the first and only time you saw him. Your thinking is biased and your brain starts to anticipate the situation that the neighbour will be unfriendly to you. So you start to feel offended and be unfriendly to your neighbour yourself. You do not smile or greet him when you pass by and you do not welcome him or offer a helping hand. The neighbour will assume that you are unfriendly yourself and will behave the same way towards you, which will make you feel as if you have been right from the beginning on.
A second example would be the following situation: You are new in a large company and you haven’t seen the top executive before. The only thing you know is that she has the biggest and most expensive car you’ve ever seen. Because in your past you had the impression that everyone you met who drove an expensive car was arrogant, you start to think that this person, too, would be very arrogant. When you have the first meeting where the top executive participates in, you talk to her in a disdainful way and through your actions let her know that you think she would not care about her employees. Receiving so much hatred and disrespect, the executive will immediately reprimand you and behave just as arrogant as you thought in the beginning she would do. Even if in fact your boss is a very nice and helpful person and would have shown it to you if you would not have approached her with your stereotype-led behaviour.