“…Maintaining close friendships is 1 We use the term linkage to refer to the level of covariation between two people in their moment-to-moment emotional responses (i.e., physiology or behavior). Other work refers to similar phenomenacovariation of emotional responses either between or within peopleas response coherence (Mauss et al, 2005), response system coherence (Ekman, 1992), organization of response components (Frijda, Ortony, Sonnemans, & Clore, 1992;Scherer, 1984;Witherington, Campos, & Hertenstein, 2001), response component syndromes (Averill, 1980;Reisenzein, 2000), concordance (Nesse et al, 1985;Wilhelm & Roth, 2001), organization of response tendencies (Lazarus, 1991;Levenson, 1994), synchrony (Danyluck & Page-Gould, 2018), and coregulation (Butler & Randall, 2013;Timmons et al, 2015). critical to psychological and physical health (Holt-Lunstad, Robles, & Sbarra, 2017) rendering the examination of these aims within the context of friendships particularly vital.…”