The mate switching hypothesis

Article history: Received 16 February 2016 Received in revised form 19 July 2016 Accepted 20 July 2016 Available online xxxx Leaving onemating relationship and entering another, serialmating, is commonly observed inmany cultures. An array of circumstances can prompt a mate switch. These include (1) unanticipated costs inflicted by one's mate, or ‘relationship load,’ not apparent on the initial mate selection; (2) changes in the mate value of either partner, creating discrepancies where none previously existed; and (3) the arrival of a new and interested potential mate of sufficiently incremental value to offset the costs of a breakup. The mate switching hypothesis suggests that these circumstances created adaptive problems throughout human evolution that forged adaptations to anticipate and appraise opportunities to mate-switch, implement exit strategies, and manage challenges confronted in the aftermath. We review several studies that support various aspects of the mate switching hypothesis: The cultivation of ‘back-upmates,’ assessingmate-inflicted costs that comprise relationship load,monitoring selfishly-skewedwelfare tradeoff ratios in a partner, gaugingmate value discrepancies, and anticipating sexual, emotional, and economic infidelities. The mate switching hypothesis provides both a complementary, and in some instances a competing, explanation to the ‘good genes’ hypothesis for why women have sexual affairs, and parsimoniously explains a host of other mating phenomena that remain inexplicable on alternative accounts. © 2016 Elsevier Ltd. All rights reserved.