Student learning in undergraduate physics laboratories has been a growing area of focus within the PER community. Lab courses have been called out as critical elements of the undergraduate curriculum, particularly with respect to improving students' attitudes and beliefs about experimental physics. Previous work within lab learning environments has focused on the effectiveness of curricular innovations or changes to pedagogy; however, one aspect of the learning environment that has not be investigated is the impact of grading practices on students' beliefs and practices. We explore the possible link between students' perceptions of what is valued and rewarded by course grades and their beliefs about the nature and importance of experimental physics as measured by the Colorado Learning Attitudes about Science Survey for Experimental Physics (E-CLASS). We find that there is a significant correlation between students' perceptions of the value of certain activities and their personal epistemologies with respect to those activities.