Motivational interviewing (MI) is a goal oriented psychotherapy involving natural conversation between a counselor and a client to instill motivation towards behavioral change in the client. Often during such an interaction, the counselor and client express themselves through nonverbal cues such as laughter. We analyze the role of laughters during MI sessions. Specifically, we perform a set of three studies to: (i) Investigate the distribution of utterances containing laughters in an MI session using Poisson process models, (ii) Analyze patterns in counselor and client behaviors with respect to laughter occurrences and (iii) Study the association of counselor utterances high in desirable behaviors such as empathy, acceptance and collaboration (referred to as BrowniePoint counselor utterances) with laughters. We quantify the impact of one persons laughter on the laughter rate of the other person. Our results show that the type of laughter (client/counselor stand alone laughter, shared laughter) can be associated with different patterns of counselor/client behaviors and depict unique relations with BrowniePoint utterances.