The storage capacity of DVD means multiple subtitle streams can be included on one disc. This has allowed some producers to include subtitle streams with experimental procedures that we will term as "abusive" subtitles (Nornes 1999). Abusive subtitles break subtitling norms in an attempt to be more faithful to the source text and increase the translator's visibility. This thesis focuses on one such abusive procedure, namely the pop-up gloss. It refers to pop-up notes that explain culturally marked items appearing in each of the semiotic channels. Already popular with amateur subtitlers of anime (Japanese animation), pop-up gloss has come to percolate into commercially released anime DVD. This thesis investigates the question as to what effect the use of pop-up gloss has on viewer perception of TV anime in terms of positive cognitive effects (PCEs) and processing effort. A second question seeks to ask the validity of pupillometric measurements for measuring the processing effort experienced while viewing subtitled AV content. A novel methodology is applied where PCEs are measured using traditional questionnaire data, while processing effort is measured using a combination of questionnaire-based data, and fixation-based and pupillometric data gathered with an eye tracker. A study with 20 subjects indicates that the use of pop-up gloss does increase the PCEs experienced by subjects regarding items the pop-up gloss describes, while more processing effort is required by viewers when pop-up gloss is used. The analysis of pupillometric data suggests that they are suitable for measuring processing effort during the viewing of subtitled AV content.