Editing Voice Principle (section)

=='''Evidence'''==
[[File:Table 1(The Voice Principle).png|thumb|500px|'''Table 1''']]
'''It is widely claimed that the use of synthetic voice in educational contexts and materials impedes comprehension and increases the cognitive load of the learners.''' 

To explore this claim, Mayer(2020) conducted five experiments on different studies in which there were comparisons between machine voice and human voice(Atkinson et al., 2005; Mayer et al., 2003; Mayer & DaPra, 2012). The results indicate that the natural human voice is much better than the synthetic voice, as it is natural and socially appealing t people. Furthermore, the experiments show that the human voice positively affects retention and transfer scores. Giving an example of showing students a 140-second narrated video of lightning formation that included spoken words(Mayer, 2003), a non-conversational Russian accent speaker and a standard accent voice speaker are provided to the learners. Students exposed to the standard voice type scored higher than the other type in the following transfer test. This leads to the conclusion that a destructive and unappealing human voice may harm people because it reduces the learner's social stimuli. 

''More research and experiments that support the Voice Principle are stated in Table 1.''