A Potential Bias in Subjective Ratings of Mental Effort

Subjective reports of listening effort are frequently inconsistent with behavioral and physiological findings. A potential explanation is that participants unwittingly substitute an easier question when faced with a judgment that requires computationally expensive analysis (i.e., heuristic response strategies). The purpose of this study was to investigate whether participants substitute the question "How did I perform?" when asked "How much effort did that take?".

Participants completed 2 sets of online surveys containing a text-based, multiple-choice synonym task. Expected performance and mental effort were manipulated across sets in 4 experiments, using a visual masking technique shown to correlate with speech-reception-testing in noise. Experiment 1 was designed to yield stable accuracy and differing effort across sets. Experiment 2 elicited differing accuracy and stable effort. Experiments 3 and 4 manipulated accuracy and performance in opposite directions. Participants included 273 adults (aged 19-68 years, M = 38.4 years).

Experiment 1 revealed no influence of perceived performance on ratings of effort when accuracy was stable. Experiment 2 showed that ratings of effort differed inversely with ratings of performance (lower performance and increased effort). Experiments 3 and 4 also demonstrated that participants rated effort in a manner inversely related to performance, regardless of the effort inherent in the condition.

Participants likely substitute an easier question when asked to rate the multidimensional construct of mental effort. The results presented here suggest that perceived performance can serve as a ready heuristic and may explain the dissociation between subjective measures of listening effort and behavioral and physiological measures.