## 3 Results
### Conventional Pupil-Size Measures
The results were similar when only including trials in which participants correctly responded to both the Verbal Task as well as the Verbal-Visual Task (the latter only for participants in the high-workload conditions), Workload: \(F(1,\,35)=6.90\), \(p=0.013\), Emotion: \(F(1,\,35)=0.15\), \(p=0.699\), and Workload \(\times\) Emotion: \(F(1,\,35)=0.13\), \(p=0.725\). Figure 2: Median diameter changes (black horizontal lines), corresponding quartiles (colored areas above and below the horizontal lines), minima and maxima (whiskers), and individual values (colored dots) of pupil diameter differences between baseline and manipulation on the \(y\) axis as a function of condition/Group (low workloads on the left, high workloads on the right; neutral-content conditions in blue, negative-content conditions in red) on the \(x\) axis. For the following analyses, participants were divided into two groups based on their self-assessment scores in the NASA-TLX's subscale \"Mental-Demand\" and the SAM's subscale \"Happiness\" (see Figures 3 and 4, respectively). Participants who scored equal or below the median score in the respective subscales were assigned to the \"low\" group, while those who scored above were assigned to the \"high\" group, and the resulting classifications were tested for their correspondences (with correspondence indicated by the symbol \"-\" in Figure 3) to the manipulations (i.e., NASA-L/SAM-HAP \(\sim\) NEUL, NASA-H/SAM-HAP \(\sim\) NEUH, NASA-L/SAM-SAD \(\sim\) NEGL, NASA-H/SAM-SAD \(\sim\) NEGH). When comparing the pupillary changes between groups based on their self-assessments, the results of the ANOVA were not significant, showing that the self-assessments should be interpreted with caution, all \(F\)s \(<\) 1.00 (NASA-TLX-Values, \(F\)[1, 35] = 0.34, \(p\) = 0.565, \(\eta^{2}\) = 0.01; SAM-Values, \(F\)[1, 35] = 0.02, \(p\) = 0.902, \(\eta^{2}\) = 0.001; (NASA-TLX-Values \(\times\) SAM-Values, \(F\)[1, 35] = 0.419, \(p\) = 0.522, \(\eta^{2}\) = 0.01). We also collapsed data across self-assessed emotions to check if this improves the picture. However, a two-sample \(t\)-test of pupil diameter changes between participants who scored high (which means that participants felt a high mental demand during the task) in the NASA-TLX subtask \"Mental-Demand\" (\(M\) = 2.37, \(SD\) = 4.02) and those who scored low (\(M\) = 1.63, \(SD\) = 3.51) showed no significant difference either, \(t(35)=-0.589, \(p\) = 0.559, \(\eta^{2}\) = 0.2 (see Figure 5). Figure 3: Average pupil diameter in pixels on the \(y\) axis as a function of the answer on the \(x\) axis, separately for different groups or conditions based on self-assessments (NASA-L, SAM-HAP \(\sim\) NEUL: low demand/happy mood; NASA-H, SAM-HAP \(\sim\) NEUH: high demand/happy mood; NASA-L, SAM-SAD \(\sim\) NEGL: low demand/sad mood; NASA-H, SAM-SAD \(\sim\) NEGH: high demand/sad mood). The two dotted lines in the colors of each graph showing the corresponding condition’s difference in average pupil size between baseline and manipulation (questions). NASA: NASA Task-Load-Index; SAM: Self-Assessment Manikin; NEU: neutral-content condition; NEG: negative-content condition; H: High; L: Low. Figure 4: Median diameter changes (black horizontal lines), corresponding quartiles (colored areas above and below the horizontal lines), minima and maxima (whiskers), and individual values (colored dots) of pupil diameter differences between baseline and manipulation on the \(y\) axis as a function of condition/Group (low self-assessed mental-demand scores on the left, high self-assessed mental-demand scores on the right; low self-assessed happiness scores in orange, high self-assessed happiness scores in blue) on the \(x\) axis. SAM: Self-Assessment Manikin. Figure 5: Pupil diameter on the \(y\) axis as a function of the question answered on the \(x\) axis and whether participants scored high (red graph) on the NASA Task-Load-Index (NASA-TLX “Mental-Demand” subscale) or if they scored low (blue graph).