**Note**: This project includes one analysis of data shared with our lab, under permission granted through a formal request to use that data via the authors' web site. To reproduce all results, this dataset will be needed. - Data on trait judgments towards Karolinska faces (male and female) from Alex Todorov's lab (http://tlab.princeton.edu/databases/karolinskafaces/) Oosterhof, N. N., & Todorov, A. (2008). The functional basis of face evaluation. Proceedings of the *National Academy of Sciences*, *105*(32), 11087-11092. As well, please note that code generating trait vector correlation values analyzed here uses the Basel Face Model (https://faces.dmi.unibas.ch/bfm/; Walker & Vetter, 2017). Walker, M. & Vetter, T. (2016). Changing the personality of a face: Perceived Big Two and Big Five personality factors modeled in real photographs. Journal of Personality and Social Psychology, 110(4), 609-624. --- **Abstract** Humans seamlessly infer the expanse of personality traits from others’ facial appearance. These face impressions are highly intercorrelated with one another, within a structure known as ‘face trait space’. Despite inquiry into the function of face trait space, theoretical and empirical accounts of its determinants are lacking. Classic theory in impression formation emphasized that perceivers use their beliefs in how personality traits correlate to form initial trait impressions, for instance, where trustworthiness of a target may inform impressions of their intelligence to the extent one believes the two traits are related. This considered, we explore the possibility that a ‘conceptual trait space’ —how human perceivers believe personality traits correlate in others— plays a role in face impressions, tethering face impressions to one another and thus shaping face trait space. In Study 1, we found conceptual and face trait space explain considerable variance in each other. Study 2 found that participants with stronger conceptual associations between two traits judged those traits more similarly in faces. Importantly, using a face image classification task, Study 3 found participants with stronger conceptual associations between two traits used more similar facial features to make those two trait impressions of faces. Together, these findings suggest our lay beliefs of how personality traits correlate may shift how we make trait impressions and thus alter face trait space. This implies face impressions are not only derived bottom-up from facial features, but are also shaped by our subjective conceptual beliefs.