The aim of the study was to examine how the wording of a question about audio, visual and audiovisual stimuli can affect the assessment of the environment. The participants of the psychophysical experiments were asked to rate, on a numerical scale, audio and visual information both separately and together, combined into mixes. A set of questions was used for all the investigated audio, visual, and audio-visual stimuli. The participants were asked about the comfort or the discomfort caused by the perceived stimuli presented at three different sound levels.
The results show that there are no statistically significant differences between the assessment of comfort and discomfort associated with visual samples. Actually, the comfort and discomfort ratings are equivalent to the extent that a discomfort rating can be represented as the opposite to the comfort rating, i.e. the discomfort rating is equal to the 10 minus comfort rating.
In general, the results obtained for audio and audio-visual samples were the same, with only a few exceptions that were dependent on sound level. No statistically significant differences were found for the loudest stimuli, but there were some exceptions for the softener cases. Based on the results, we show that only for visual stimuli both scales are totally interchangeable. When presenting audio and audio-visual samples, only one scale should be applied – either discomfort or comfort, depending on the context and the character of the stimuli.

The present study consisted of two experiments. The goal of the first experiment was to establish the just noticeable differences for the fundamental frequency of the vowel /u/ by using the 2AFC method. We obtained the threshold value for 27 cents. This value is larger than the motor reaction values which had been observed in previous experiments (e.g. 9 or 19 cents). The second experiment was intended to provide neurophysiological confirmation of the detection of shifts in a frequency, using event-related potentials (ERPs). We concentrated on the mismatch negativity (MMN) - the component elicited by the change in the pattern of stimuli. Its occurrence is correlated with the discrimination threshold. In our study, MMN was observed for changes greater than 27 cents - shifts of ±50 and 100 cents (effect size - Cohen’s d = 2.259). MMN did not appear for changes of ±10 and 20 cents. The results showed that the values for which motor responses can be observed are indeed lower than those for perceptual thresholds.