SONIC Lab is proud to welcome Christopher Marcum, who will present a talk on Wednesday, November 4th, 2015 at 4:00 PM in the SONIC Lab in the Frances Searle Building 1-459. All are welcome to attend.

To schedule a one-on-one meeting with Dr. Marcum please schedule a time here.



An Ego-Centric Relational Events Model of Buffet Selection Processes in an Experimental Virtual Reality Setting


The relational events model (REM) framework for social action (Butts 2008) has recently been demonstrated to be useful as a model of a wide range of temporally unfolding events and not just limited to the dyadic case as originally designed. The framework has shown promise, for example, in modeling ego-centric studies, as well as event histories that involve multiple event types and exogenous events (Marcum & Butts 2015). Additionally, recent work has demonstrated how careful use of support constraints within the REM framework facilitates its application in experimental designs (Tranmer et al. 2015). We extend this line of research by combining these various generalized applications of the REM in a single scenario—ego-centric event histories with multiple event types and support constraints in an experimental design.

Two hundred twenty-one overweight mothers of children between 4 and 5 were randomized to one of four feedback conditions that emphasized different health information about eating and health: 1) food safety control (Control); 2) behavioral-risk information; or 3), behavioral-risk information plus personal family health history-based risk assessment. After a short survey was administered to the participants and they were given their randomly selected feedback to read, each mother put on a head-mounted display helmet and was immersed in a virtual buffet environment. In the buffet, mothers selected from a set of virtual food and drink choices for their child’s lunch. Prior work (McBride et al. 2013) has shown that the feedback conditions deferentially impacted the total number of calories on the plate at the end of the simulation. Here, however, we evaluate whether the behavioral food selection process giving rise to those choices also differs by feedback condition.

We use the REM framework to address a simple research question: 1) to what extent do the feedback conditions shape the behavioral process unfolding during the buffet simulation? We specify sufficient statistics for both environmental and behavioral constraints on the buffet selection process. These include structural statistics for the food ordering effects and differential serving sizes, and behavioral statistics for choice inertia, “saving dessert for last” and “grazing versus browsing.” Preliminary REM results show evidence of differential preferences for the rate at which certain foodstuffs are selected, that smaller portion size drives actors to make multiple selections of the same foodstuff in a row, healthful choices are likely to precede unhealthful ones, and spatial ordering effects. Differential impacts of the feedback condition on the behavioral selection process will be discussed in the context of REM model selection.


Dr. Marcum received his Ph.D. in sociology from the University of California-Irvine in 2011. His dissertation research focused on health and social structural explanations of age differences in daily social interactions. His current research seeks to understand how health shapes family network processes across the life course, on the one hand, and to develop statistical models for network analysis on the other. Through his methodological work in mathematical sociology he has demonstrated expertise in modeling a wide range of social systems, including: interorganizational disaster response networks, relational events processes, epidemic dynamics, and inter-generational communication.


A recording of Christopher Marcum’s Presentation can be found here, or can be viewed below!