Clark joined the doctoral program in fall 2013. His research interest primarily concerns how consumers cope with their fundamental needs (e.g., desire for control, need for exploration) via such behaviors as collecting. In doing so, Clark attempts to shed light on important aspects of the human condition by taking a consumer behavior perspective. His research tools range from lab and field experiments to functional neuroimaging. His dissertation investigates how consumers are motivated to complete their collections driven by the desire for control. On the other end of the collecting behavior spectrum, he also examines how expanding a collection can fulfill the innate consumer need for exploration. Clark strives to demonstrate how ordinary, everyday consumer behaviors such as collecting can fulfill both defensive (e.g., safety, control) and exploratory (e.g., curiosity, personal growth) consumer needs.