Mate Guarding and Partner Defection Avoidance

Successful mating requires the investment of resources, from genetic material and metabolic resources to time, money, and social support. This investment can be distributed across numerous low-investment short-term partnerships, concentrated on one high-investment long-term partnership, or some combination of partnerships of varying lengths and levels of investment. When the risks are low and the benefits are high, both men and women can be motivated to pursue a long-term strategy supplemented with short-term partnerships. While this can be beneficial for the person using this supplemented strategy, it can be costly for the long-term partner who is consequently at risk of losing their own investments in the event of their partner’s defection. Therefore, both men and women have evolved motivations to protect against the loss of investment in a relationship via mate-guarding behaviors. These behaviors can function by enticing a partner’s continued investment in the ongoing relationship, by reducing a partner’s available alternatives to the ongoing relationship, or by punishing or threatening to punish a partner’s defection from the ongoing relationship. Use of these mate-guarding strategies is moderated by individual difference and contextual factors that affect the costs and benefits of engaging in mate-guarding behaviors. In short, both men and women are most likely to engage in mate-guarding behaviors when the risk and cost of losing a partner-and so the risk of losing one’s investment in the ongoing relationship-is comparatively high.