||Pupil dilation measures provide a useful index of test-taking processes. Prior research has established a simple positive relationship between pupil dilation magnitude and (i) threat levels, (ii) task difficulty levels, and (iii) working memory capacity. Surprisingly few studies have investigated the interaction of these three pupil response drivers. Do they add in a linear fashion, like separate weights on a single scale (as the "load" metaphor suggests), or is their relationship more complicated? To test of this question, I used a 2 X (2 X 3) mixed experimental design with random assignment to working memory resource depletion and nondepletion groups. These groups completed two versions of the same task, where response inhibition is required repeatedly in the depleting but is not required in the nondepleting version. Next, all subjects completed a test (90 factor-multiple judgment items) that employed two levels of difficulty (easy and difficult) and three levels of threat (safe, partially cued threat, and fully cued threat). Testtaking pupil data were collected at 60 Hz using a Tobii eye-tracker. Results indicated that levels of threat and task difficulty independently contribute to pupil response magnitude and they do not moderate one another. Apparently, the effects of difficulty and threat are not moderated by resource depletion; however, this study lacked power to detect anything less than a strong depletion effect. Results indicate that test-taking pupil responses are sensitive to testing conditions (e.g., threat and difficulty), but it remains unclear whether these responses are also sensitive to priming conditions (e.g., resource depletion).