Despite requirements for Responsible Conduct of Research (RCR) training, little is known about how much this training actually influences the thinking and behaviors of participants. Interview-based qualitative research methods were used to study the reactions of Ph.D. students and postdoctoral fellows to what was taught in an RCR course. For trainees with limited prior RCR experience, or who agreed with what was taught, it was relatively easy to influence their attitudes and how they thought they would use the new information in the future. However, if their prior experiences or existing knowledge conflicted with what was taught they resisted and often rejected new ideas that were presented. Interviews also revealed the tremendously complex process trainees must undergo trying to resolve or integrate all of the different perspectives they receive on RCR from other sources. These results revealed the importance of viewing RCR training from the perspective of learning theory and how prior knowledge influences what people learn. The results also support the need for periodic rather than one-time RCR training to counter the often conflicting views and practices young scientists experience in real-life research settings.