Final answer:
Marshall Sahlins identified the original three types of reciprocity: generalized, balanced, and negative, detailing different social exchange systems from close family ties to market transactions among strangers.
Step-by-step explanation:
The anthropologist who came up with the original three types of reciprocity was Marshall Sahlins. His work identified three forms of reciprocity common in various societies: generalized reciprocity, balanced reciprocity, and negative reciprocity. Generalized reciprocity resembles altruism and functions largely without the expectation of immediate or exact returns, often seen in closely-knit social units like families. Balanced reciprocity involves a more immediate exchange where the value of gifts is considered, reflected in exchange practices among wider social circles such as friends or extended community members. Lastly, negative reciprocity is the type of exchange wherein parties aim to get the better deal, often with strangers or in markets where competition is high.