My research focuses on understanding the formation, maintenance, and functions of personal relationships during adulthood. My work in recent years has been influenced by attachment theory and recent conceptualizations of responsiveness in relationships. Specifically, I have been investigating the mechanisms by which close relationships influence relational and psychological well-being and physical health over time (e.g., Ong, Gardner, Urganci, Gunaydin, & Selcuk, 2020; Selcuk, Gunaydin, Ong, & Almeida, 2016; Selcuk & Ong, 2013; Selcuk, Stanton, Slatcher, & Ong, 2017; Selcuk, Zayas, Gunaydin, & Hazan, 2012; Slatcher & Selcuk, 2017; Slatcher, Selcuk, & Ong, 2015; Stanton, Selcuk, Farrell, Slatcher, & Ong, 2019; Tasfiliz, Selcuk, Gunaydin, Slatcher, Corriero, & Ong, 2018). In other lines of work, I am interested in understanding the links between marital processes and parenting (Kocak Mouratidis, Ucanok, Selcuk, & Davies, 2020; Selcuk et al., 2010) and factors influencing early-stage person perception and relationship formation (e.g., Gunaydin, Selcuk, & Zayas, 2017; Gunaydin, Zayas, Selcuk, & Hazan, 2012), mate selection and relationship maintenance (e.g., Gunaydin, Selcuk, & Hazan, 2013; Gunaydin, Selcuk, Yilmaz, & Hazan, 2018), friendships (Gillath, Karantzas, & Selcuk, 2017), and daily happiness and well-being (Bayraktaroglu, Gunaydin, Selcuk, & Ong, 2019; Gunaydin, Selcuk, & Ong, 2016).