Gall (2004) points out that Mayer’s research has tended to focus mainly on the understanding of physical and mechanical systems, and thus raises the question of how applicable his results are to nondidactic, immersive learning environments. This criticism of whether results obtained in controlled experimental situations can be applied to dynamic classrooms and learning environments is an old complaint that has been leveled at psychology since psychologists first began studying and trying to measure learning. Often, these charges of non-relevance to real-life learning and instruction have been justified. But Mayer is careful not to claim that his research should be seen as the final word on instruction in the situations he is trying to measure. Rather, it is obvious in the evolution of the cognitive theory of multimedia learning that they are only trying to determine what appears to make a difference in learning situations, hypothesize about it, and then continue to look for better explanations and hypotheses. The theory is dynamic and the expectation that it will continue to grow, adapt, and change appears frequently in the literature.