This type of altruism is very rare, and is thought as a key to human success. We socialize with friends, strangers and non-relatives, which is different from kin selection because you are not doing this to pass down our own genes through relatives. Reciprocal altruism is different in this sense because the whole group benefits together.
Reciprocal altruism is thought to be our evolutionary roots of moral behavior, gratitude, guilt, trust, and so on, as a way to socialize with others to benefit each other.
This behavior is also seen in other organisms, for example, vampire bats. Since these bats lose heat quickly due to their high surface area to volume ratio, they tend to starve quickly. Hence, bats even make friendly relationships with non-relatives to donate or receive blood when either of them are starving.