Syntactic and Lexical Priming Social Networks: A Complex Contagion Approach to Language Diffusion

Language is a dynamic and adaptive system that is shaped by multiple factors. While certain words or phrases become widely used, others do not. This thesis explores how linguistic behavior spreads across groups. It examines whether language spreads in the same way as other social behaviors by drawing on complex contagion theory (Centola, 2019). According to this theory, people need to be exposed to a behavior from multiple people before they adopt it, especially if the behavior is costly or risky. To investigate this, four experiments were conducted. The first experiment tested whether people are more likely to use a sentence structure when they hear it from multiple speakers rather than just one, everything else being equal. The second experiment investigated whether the structure of a social network, i.e., how people are connected, affects how language spreads. The third experiment examined the influence of group size on language spread. Finally, the fourth experiment examined whether where the behavior starts spreading in the network affects the spread of language. Across all four studies, participants consistently used the linguistic forms, regardless of how many different speakers they were exposed to, how the network was structured, or how large the group was. These results suggest that even a single source of exposure to a word or structure can lead to their use, akin to how a piece of information or a catchy phrase might go viral. The findings challenge the idea that linguistic behaviors need repeated exposure or social reinforcement to spread. Instead, for syntactic and lexical choices that are low-risk and easy to process, people may use them after being exposed to them from just one source.