Multimedia Input Modes, the Modality Principle, and the Redundancy Principle for University ESL Students’ Learning

This study compared three multimedia input modes in the modality and redundancy principles (Mayer, 2009) in terms of university ESL (English as a Second Language) students’ learning and examined the applicability of the modality and redundancy principles for ESL students. Mayer’s modality and redundancy principles (2009) inform the design of effective multimedia lessons. However, the two principles originally stemmed from experimental studies examining students’ learning in their native language and did not include ESL students in the discussion. Based on the modality and redundancy principles, added on-screen text and graphics lead to an overload in learner’s visual channel, which undermines learning (Clark & Mayer, 2011). For ESL students’ multimedia learning, the cognitive theory of multimedia learning (Mayer, 2009) suggests that on-screen text in the input modes of graphics + text and graphics + audio + text might overload the visual channel to impede learning. However, according to the cognitive load theory (Sweller, 2014), text might also reduce the processing demands for identifying and decoding auditory input to facilitate learning. Due to the limited number of empirical studies, it was inconclusive if verbatim text aids or hinders ESL students’ learning, and it was unclear if the modality and redundancy principles apply for ESL students. An initial Study addressed common validity issues, such as lack of control of instruments and materials, in related studies, and it quantitatively tested the applicability of the modality and redundancy principles for ESL students’ learning. Both knowledge retention and vocabulary test results indicated that input modes did not have an impact on ESL students’ learning, and consequently the modality and redundancy principles were insignificant. An additional study, Study 2, addressed the implementation issues and limitations of Study 1 to provide more rigorous findings. Based on the findings of both Study 1 and Study 2, the modality and redundancy principles did not apply for ESL students’ content knowledge and vocabulary learning when certain multimedia learning principles were followed. Both Study 1 and Study 2 extended Mayer’s modality and redundancy principles by examining their applications to ESL students, as well as provided empirical evidence for designing effective multimedia instruction for ESL students

Essays in Health Economics

We investigate the direct and indirect effects of employment decisions on body weight. We formulate a dynamic model in which an individual makes decisions in three stages in each period. He first chooses an occupation and realizes his wage. Then he decides how to allocate money and time. As a result of his choices, his body weight updates in the last stage. Using data from PSID and U.S. Census Bureau, we estimate a joint system of equations and use a flexible error structure to account for selection on unobservables. We find that employment decisions have insignificant effects on body weight because individuals choose to compensate for changes in the workplace by adjusting their off-work food and exercise behavior