ZHOU and Fabian take an empirical approach to exploring a fascinating topic: the relationship between "fast" performances and virtuosity. Although their methodology is largely exploratory and perhaps flawed in certain respects if viewed from a strictly scientific perspective, it nonetheless presents some intriguing evidence that the tempo extremes in a musical performance are hallmarks of virtuoso playing.

The approach of examining recordings by a variety of pianists classified as virtuosos or non-virtuosos is generally sound. The authors mined published reviews of the recordings selected for analysis, searching for references to various forms of the word "virtuosity". However, the initial process of choosing the artists could have been more systematic. Due to the way the pianists were chosen, there was an uneven number of reviews for each recording, thus making the frequency of "virtuosity" terms unreliable for determining whether a performer was a virtuoso or not. It seems unfair to characterize a performer in the non-virtuoso category if they have no reviews (although a counterargument might be that the very lack of a review is indicative of a lesser performer, thus a non-virtuoso). Having a roughly equal number of virtuosos and non-virtuosos in the corpus would have resulted in a more balanced data set and consequently more reliable results, especially since performances were compared against an average that included two virtuosos and eight non-virtuosos instead of a direct comparison between two groups.

The authors constrained the sample to pianists similar in age as well as recordings within a restricted date range to "control for sound quality as well as potential historical differences in style and recording technology." Recording quality should not be an issue; as long as a given recording is clear enough for note onsets to be distinguishable, a tempo analysis can be conducted. One could imagine how the issue regarding historical differences in style might affect the results for certain types of music where interpretation has been subject to a great deal of change in recent decades (in Baroque music, for example), but it is not a convincing enough argument, given the repertoire, to limit the data to a narrow recording time period. There is a natural upper bound to how fast any difficult passage can be played accurately and coherently; a true virtuoso, regardless of time period, should have the appropriate technique to execute such passages close to that bound, unless the recordings are so old that the instrument employed has changed fundamentally, which is hardly the case with the modern piano over the past century. If Zhou and Fabian's findings hold for a broader range of recordings, that would provide powerful support for their argument. Perhaps a more valid reason for analyzing only recent recordings is the availability of reviews. However, this is not one of the points mentioned as a justification.

Looking at notoriously technically difficult pieces would be another path to explore in future work. Granted, such pieces might not be recorded as often because of their extreme level of difficulty, but a case can be made for selecting works that are more difficult than Chopin Ballade No. 1 and Liszt Sonata in B minor. While those two pieces are staples of the piano repertoire, they do not stand out as particularly virtuosic pieces when compared to other commonly recorded pieces by Chopin and Liszt; Chopin's sonatas and etudes as well as Liszt's Transcendental Etudes are more technically challenging, to name a few examples. Then there are pieces such as Brahms' Paganini Variations that are arguably more difficult than anything composed by Chopin or Liszt. True virtuosos are able to play the most difficult repertoire in a manner that sounds effortless. Any serviceable professional pianist would be able to play Chopin's Ballade No. 1 without too much trouble, but very few would be able to execute Chopin's Etude Op. 25, No. 6 at the tempo indicated by the composer.

Then there is the question of what is actually virtuosic versus what sounds virtuosic. Plenty of piano repertoire sounds virtuosic, but is not necessarily difficult to play. For example, Liszt Piano Concerto No. 1 might sound flashier than Brahms Piano Concerto No. 2, but it is far less technically demanding––there is a reason you never see 10-year-old prodigies playing Brahms piano concertos. A study that looks in depth at how virtuosity by a general audience is perceived versus how a professional pianist might perceive it could provide a complementary perspective, serving as a counterpoint to the insights outlined in the current study.

Despite the potential methodological issues discussed above, the results of Zhou and Fabian's study are intuitively compelling. Their insights on how contrasting tempo extremes are significant markers of virtuosic performances ring true. I believe they have successfully illuminated a characteristic of how listeners perceive virtuosity by presenting empirical evidence in support of this. Virtuosos bring to mind effortless, brilliant technical prowess. However, this study shows that there is particular power in contrasts. Just as a happy occurrence is made more joyful by preceding gloom, a fast passage is rendered perceptually more virtuosic when juxtaposed alongside an exceptionally slow one.