Opposing this idea, Zanon (2006) argues that many viewers consider subtitles a nuisance because they cover visual information and so lessen the credibility of the film. Bird and William (2002) claim that it remains unclear whether subtitles lead to better or worse listening comprehension. They argue that although some studies suggest that subtitles have some beneficial effects, it may be that text presents the easiest path to comprehension. In other words, the improved comprehension of a video plot and a better retention of phrases and vocabulary could be due only to good reading, not improved listening comprehension.