Much research on human sexuality and romantic relationships has focused on two polar-opposite relationship types: long-term, committed relationships like marriage (Buss, 1989; Christopher & Sprecher, 2000; Li, Bailey, Kenrick, & Linsenmeier, 2002) and short-term, casual-sex relationships like one-night stands or hook-ups (Cubbins & Tanfer, 2000; Fisher & Byrne, 1978; Li & Kenrick, 2006; Paul, McManus, & Hayes, 2000). Although insightful, such research is nevertheless limited. It is common for people in nearly all societies to form long-term bonds and marry (e.g., Fisher, 1992), and anonymous casual sex is variably present in most societies (e.g., Schmitt, 2005), despite the cultural and religious taboos or prescripts from engaging in that behavior. However, a growing body of evidence suggests the range of potential relationships is larger than these two alone. Recent research expands the variety of relationships to include ones where partners have some degree of sexual contact and some degree of friendship, but the partners are not in a committed relationship. Some research has focused on "friends with benefits" (e.g., Afifi & Faulkner, 2000), whereas other research has focused on "booty-call (1) relationships" (e.g., Jonason, Li, & Cason, 2009). In this study, we focus on booty-call relationships. Whatever term is used to refer to non-romantic sexual relationships, they share several features. These relationships appear to be simultaneously motivated by both short-term (e.g., physical attractiveness is prioritized) and long-term relationship (e.g., repeated interactions) factors (Jonason et al., 2009). Both relationships are likely to be appealing to men and women for different reasons. The low-investment sexual component may appeal to men (Buss & Schmitt, 1993; Townsend, 1995; Townsend, Kline, & Wasserman, 1995; Townsend & Levy, 1990), and a prolonged period of interaction allows women to give mates a "trial run" (Greiling & Buss, 2000; Impett & Peplau, 2003; Jensen-Campbell, Graziano, & West, 1995; Li & Kenrick, 2006). If a relationship is a trial run, the partner has likely passed the minimum threshold and is being given the opportunity to prove their worth as a serious partner. Alternatively, although not particularly well borne-out in the data, these relationships may function as a "placeholder relationship" until a better relationship comes along or as a source of stable social or emotional support that cannot be provided in one-night stands. (2)
