Cognitive experiments on timing lag for superimposing closed captions

This paper describes cognitive characteristics of timing difference for closed captions superimposed onto TV news programs. It was reported that timing delays for superimposing disrupts hearing impaired people's enjoyment and intelligibility of TV, but nobody has yet investigated the permissible limit for timing difference. This study presents subjects' permissible and preferable limits of the timing differences and also the correlation between the limits and the four factors: subject groups, news contents, caption formats and the direction of timing difference. Significant difference between the hearing impaired and the hearing was recognized for those limits. For the permissible limit of the hearing impaired, significant difference was recognized in subject groups and caption formats. For captions outside the picture, the limits for the deaf and late-deafened were 3.95 and 4.94 s, respectively. For caption inside the picture, the permissible limit for the late-deafened was 1.63 s, but that for the deaf was not recognized. For the permissible limit of the hearing impaired, significant difference was recognized only in caption formats and the limits by caption formats were 5.38 and 1.39 s for the outside and inside formats, respectively.