My research focuses on social development across the lifespan, with a primary aim of understanding the formation, maintenance, and functions of close relationships during adulthood.  In my research I integrate theories and methods of social development with the closely related field of social psychology. My work in recent years has been influenced by attachment theory and recent conceptualizations of responsiveness in close relationships. Specifically, I have been investigating the psychological mechanisms by which close relationships influence emotion regulation, psychological well-being, and physical health over time (e.g., Selçuk, Günaydın, Ong, & Almeida, 2016; Selçuk & Ong, 2013; Selçuk, Stanton, Slatcher, & Ong, 2017; Selçuk, Zayas, Günaydın, & Hazan, 2012; Slatcher & Selçuk, 2017; Slatcher, Selçuk, & Ong, 2015; Taşfiliz, Selçuk, Günaydın, Slatcher, Corriero, & Ong, 2018). In other lines of work, I am interested in understanding factors influencing early-stage person perception and relationship formation (e.g., Günaydın, Selçuk, & Zayas, 2017; Günaydın, Zayas, Selçuk, & Hazan, 2012), mate selection and relationship maintenance (e.g., Günaydın, Selçuk, & Hazan, 2013; Günaydın, Selçuk, Yılmaz, & Hazan, 2018), and daily happiness and well-being (Bayraktaroğlu, Günaydın, Selçuk, & Ong, in press; Günaydın, Selçuk, & Ong, 2016). Lately, I have been exploring implications of family psychology research for sustainability of family businesses.