Social relationships permeate consumers' interactions with both the marketplace and consumption more broadly. Imagine a consumer, Sam, walking through a department store. Sam hopes to buy a birthday present for their best friend, pick up socks for their spouse, find a microwave that will be more accessible for their aging parents, pick up a bedding set for themselves and their spouse, and find something to wear at an upcoming wedding. Any individual consumer, on any given trip, may be shopping for themselves (such as the wedding outfit) or for both themselves and someone else (such as the bedding set), but they also might be buying solely for someone else for a number of reasons, including gifting, providing favors, and caretaking (P. J. Liu et al., 2019). Now imagine that Sam is not alone in the store but brought along their spouse, Joe, and called their sister, Carmen, while picking a microwave for their parents as they are splitting the cost. In this situation, the purchase decisions become joint decisions, which can further shape the decision-making process and the decisions made. Joe might be more price sensitive than Sam and expand Sam' s consideration set by price-checking the products online. Or Joe might feel impatient with clothes shopping and rush Sam through picking a wedding outfit. On the other hand, Carmen might prioritize their parents' preferences and push for Sam to buy the higher quality, but more This chapter is based on the first author' s dissertation.