Induced Cognitive Load Influences Unpleasantness Judgments of Modulated Noise

Attentional processes highly govern the perception and evaluation of environmental sounds. Based on a cognitive load theory of attention assuming that the perception or ignoring of a stimulus depends on the degree of cognitive load related to a distracting task, we conducted a laboratory experiment to investigate sound evaluations under high and low cognitive load. Acoustical stimuli consisted of amplitude-modulated pink noise differing in sound level and modulation frequency. Utilizing a within-subjects design, two listening conditions were implemented with differing levels of induced cognitive load. In the low-load condition, participants solely listened and retrospectively evaluated the stimuli regarding their unpleasantness. In the high-load condition, they also performed the Stroop color-word interference test during the stimulus presentation. Cognitive load was continuously measured using pupillometry which confirmed the expected significant differences across conditions. Results further supported our hypothesis that, overall, participants perceived the sounds as less unpleasant in the high-load condition compared to the low-load counterpart. Also, interaction effects were observed between loudness and listening condition, which might be explained by a central tendency bias in the high-load condition. Implications for the design of listening experiments and the effect of sound on cognitive tasks are discussed.