Invested mental effort and perceived task difficulty are strongly correlated yet relate differently to relative task difficulty, indicating the two ratings measure different aspects of overall cognitive load¶

Claim · All claims
Evidence · 1 study (2 entries) · associational r1–r2 · q2 · i3 large
Currency · newest study 2025 · checked against its sources 2026-10-21 (automated, 2 of 2 entries) · not reviewed by a person

Subclaims¶

q2 i3 Invested mental effort is strongly correlated with relative task difficulty (r = -0.69) and with perceived task difficulty (r = 0.78). → Schuessler 2025 q2 i? The correlation between invested mental effort and relative task difficulty differs significantly from the correlation between perceived task difficulty and relative task difficulty (z = 3.75, p ≤ 0.001). → Schuessler 2025 (2)

Evidence¶

Schuessler 2025¶

Schuessler, K., Fischer, V., & Walpuski, M. (2025). Investigating construct validity of cognitive load measurement using single-item subjective rating scales. Instructional Science. https://doi.org/10.1007/s11251-024-09692-6

q2 · i3 · associational · r1

Task-level correlation analysis (Ntasks = 32, all p's ≤ .001 as printed in Table 4): the printed effect size r = 0.78 links invested mental effort with perceived task difficulty, and Table 4 reports r = -0.69 with relative task difficulty, the negative sign being a Rasch-scaling artifact.

"The correlation between the two cognitive load measures (invested mental effort and perceived task difficulty) was 0.78 (see Table 4)."

Schuessler 2025 (2)¶

Schuessler, K., Fischer, V., & Walpuski, M. (2025). Investigating construct validity of cognitive load measurement using single-item subjective rating scales. Instructional Science. https://doi.org/10.1007/s11251-024-09692-6

q2 · i? · associational · r2

Dependent-samples comparison of correlations on the same 32 tasks: the mental-effort/relative-difficulty correlation (r = -0.69) differs significantly from the perceived-difficulty/relative-difficulty correlation (r = -0.91); the article prints only the z statistic and p for the comparison.

"reveals a significant difference, z = 3.75, p ≤ 0.001 (please note this is a comparison for dependent rs)."

Discussion¶

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