With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Friendship has been studied in academia.
text_B: Friendship is a relationship of mutual affection between people .. affection. affection. Friendship is a stronger form of interpersonal bond than an association .. interpersonal bond. Interpersonal relationship. Friendship has been studied in academic fields such as communication , sociology , social psychology , anthropology , and philosophy .. communication. Communication studies. sociology. sociology. social psychology. social psychology. anthropology. anthropology. philosophy. philosophy. Various academic theories of friendship have been proposed , including social exchange theory , equity theory , relational dialectics , and attachment styles .. social exchange theory. social exchange theory. equity theory. equity theory. relational dialectics. relational dialectics. attachment styles. attachment styles. A World Happiness Database study found that people with close friendships are happier .. Although there are many forms of friendship , some of which may vary from place to place , certain characteristics are present in many types of bond .. Such characteristics include affection ; sympathy ; empathy ; honesty ; altruism ; mutual understanding and compassion ; enjoyment of each other 's company ; trust ; and the ability to be oneself , express one 's feelings , and make mistakes without fear of judgment from the friend .. affection. affection. sympathy. sympathy. empathy. empathy. honesty. honesty. altruism. altruism. understanding. understanding. compassion. compassion. trust. Trust ( social sciences ). While there is no practical limit on what types of people can form a friendship , friends tend to share common backgrounds , occupations , or interests and have similar demographics .. demographics. demographics
related.