College coursework requires students to use their critical thinking skills in order to succeed in classes. Current culture in higher education assumes that students arrive to college with a well developed set of critical thinking skills or that they are able to develop the necessary skills on their own. This assumption is especially evident in science coursework, where the students are asked to use their critical thinking on everyday basis (doing lab work, solving the problems), but are rarely taught how. The lack of these skills puts students at a great disadvantage. First generation students are especially at a disadvantage because they usually arrive to college less prepared than their peers from families where parents have had some college education. We propose that the absence of critical thinking manifests itself in low test scores. We investigate this connection by observing the relationship between student test scores before and after the set of exercises developed to develop critical thinking and scientific expression in the introductory physics class environment.