Researchers are learning how to prevent the projected United States shortage of science, technology, engineering, and mathematics (STEM) professionals by retaining more undergraduates in STEM majors. Specifically, since undergraduates generally want to give back to their communities, they experience heightened science career motivation once they "fit" their communal goals with their views of science careers. However, testing the quality of fit is challenging because individuals differ in communal goals and views of science. For the present study, therefore, a person-centered analytical approach was used to identify groups of STEM undergraduates defined by combinations of communal goal endorsement and perceived communal goal affordances. Four groups were identified: Low Incongruent, Moderately Low Incongruent, Average Congruent, and Moderately High Incongruent. Results showed that undergraduates were optimally motivated when both communal goal endorsement and perceived communal goal affordances were moderately high and incongruent. Results also showed that gender and cultural identity could predict group membership.