Date of Award

Summer 2023

Document Type

Thesis (Master's)

Department or Program

Psychological and Brain Sciences

First Advisor

Dr. Meghan L. Meyer

Second Advisor

Prof. Luke J. Chang

Third Advisor

Dr. Jeremy R. Manning


Social interactions are multifaceted, complex, and critical to social behaviour as they help gather information, develop social connections, and regulate social behaviour (Lakey & Orehek, 2011; Testard et al., 2021; Jolly & Chang, 2021). Among social interactions, conversations find a special place for humans due to the nuances associated with language, conversational behaviour (e.g., gestures), and context (e.g., where conversations occur and what is discussed). Researchers have studied aspects of single conversation behaviour, content related to conversations, and brain function (Sievers et al., 2020). However, little is known about the brain function of densely-sampled in-person conversation behaviour. Filling this gap is important, given that real-world conversation happens frequently and is an index of social connectedness. We utilise the passive-mobile sensing approach from the StudentLife study (Wang et al., 2014; daSilva et al., 2021) to track real-world conversations and relate the features to resting-state functional connectivity via fMRI. In this thesis, we show that resting state functional connectivity of left inferior frontal gyrus (LIFG, a region associated with language; Turken & Dronkers, 2011; Klaus & Hartwigsen, 2019) with the dorsomedial prefrontal cortex (dMPFC) subsystem of the default mode network (DMN), which is a network associated with social-cognitive processes (Collier & Meyer, 2020; Sippel et al., 2021), of an individual is related to the time they spend in the vicinity of conversations. Consistent with social psychological literature (Delormier, Frohlich, & Potvin, 2009; Dunbar, 2017), we also find that features of conversation – average time spent, the variance associated with, and total time spent around conversations – at places associated with ‘social eating’ was related to the same brain function. Our results suggest that the importance of LIFG within the dMPFC subsystem may be associated with (1) average time spent around conversations generally, and (2) conversations occurring specifically in socially relevant situations. This thesis also supports that passive-mobile sensing can be useful to study real-world conversations, and that adding neuroimaging modalities to otherwise densely-sampled behavioural features can open new avenues of research to better understand the brain-basis of social interactions.