Effective science communication is a common goal scientists share, but explicit science communication curriculum is lacking in undergraduate science programs. Although course-based research experiences (CUREs) can provide opportunities for students to practice their communication skills, the literature lacks consistent investigations of oral communication activities and their impact on student outcomes. Furthermore, the emergence of COVID-19 has added a sudden challenge, about which little is known, to improving student outcomes in CUREs. This dissertation evaluates the role research posters play in students' self-perceptions of science identity, science communication self-efficacy, value, and skills gained in two different course modalities: hybrid and face-to-face. Using a convergent mixed-methods design, I collected quantitative and qualitative self-perceptions across two hybrid semesters and one face-to-face semester from an introductory plant biology CURE. I used a repeated measures posttest approach to isolate poster design and presentation experiences from research aspects, and to collect quantitative perceptions of science identity and communication self-efficacy. I also collected qualitative perceptions of science identity and communication self-efficacy in one-on-one semi-structured student interviews, and qualitative perceptions of value and skills gained from the poster experience from open-ended survey responses. Within both modalities, I found students' science identity and communication self-efficacy significantly improved even without an oral science communication activity. However, students' communication self-efficacy improved significantly more during the face-to-face modality when they experienced research aspects and presented at a face-to-face poster symposium. In the hybrid modality, students described benefits and complaints regarding a remote virtual research presentation, namely, reduced stress, a more comfortable atmosphere, but a murkier communication channel. In the face-to-face semester, students indicated face masks were a barrier for audio and visual communication. However, students' comments were consistent with the view that research posters were an authentic and engaging experience that improved their science presentation and conversation skills. Students gained science communication efficacy from the research experience under both modalities but presenting a poster did not enhance their efficacy further under the hybrid modality. Faculty should consider this when designing courses under the constraints imposed by the delivery format. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]