Objective This study advances the presidential primary literature in two ways. First, since many studies in this literature advocate for more detailed theoretical development, we incorporate an interdisciplinary approach by utilizing social contagion theory from the field of sociology. Second, presidential primaries do not adequately explore what role the public plays during the invisible primary. We thus incorporate Google Trends data into presidential primary models to account for the relative amount of public attention for each presidential primary candidate. Methods We use fixed effects regression to determine the impact of public attention on a candidate's share of the contested primary vote (CPV). Results We find that increased public attention leads to higher levels of support for a candidate in the Iowa caucuses, New Hampshire primary, and CPV. Conclusion These findings illustrate the extra‐voting role the public plays in presidential primary elections and helps us further distinguish how party elites, voters, and candidates uniquely determine the selection of our executive.