This paper presents an exploratory study conducted to understand the role of individual differences between designers in the function modeling process and with respect to final models. An input-process-output framework of function modeling is proposed to systematically approach this theory building and discovery research study. Four measures of individual differences are identified of interest. These include the systemizing quotient, goal orientation, risk propensity, and concept design thinking style. Each metric is composed of multiple items that can be assessed through survey instruments. A previously developed protocol study is used to capture function modeling behaviors and a final function structure model. Data collected from the survey instruments and protocol study is processed to generate input, process, and output measures. A regression-based analysis is used to identify correlations in three groups: input-process, input-output, and process-output. Potential correlations of interest are identified within each group. Implications of these correlations are discussed from a function structure modeling perspective and hypotheses for future research are identified based on the patterns observed in this study. Three testable hypotheses are proposed for future investigation: (1) Goal orientation has no effect on activity distribution in the function modeling process, (2) Thinking style has no effect on the function modeling process, and (3) Risk propensity has no effect on element distribution in the function modeling process. Finally, an anticipated experiment is outlined to investigate one of the potential relationships discovered in this study.