From a study by Pavlygina RA, Sakharov DS, Davydov VI, and Avdonkin AV:
The efficiency of recognition of masked visual images (Arabic numerals) under conditions of listening to classical (intensity 62 dB) or rock music (25 dB) increased. Coherence of potential in the frontal cortical region characteristic of the masked image recognition increased under conditions of listening to music. The changes in intercenter EEG relations were correlated with the formation of “the recognition dominant” at the behavioral level. Such behavioral and EEG changes were not observed during listening to louder music (85 dB) and listening to music of other styles, however, the coherence between potentials of the temporal and motor areas of the right hemisphere increased, and the latency of hand motor reactions decreased. The results suggest that the “recognition dominant” is formed under conditions of establishment of certain relations between the levels of excitation in the corresponding centers. These findings should be taken into consideration in case if it were necessary to increase the efficiency of the recognition.
This study shows that listening to classical music at 62dB (about as loud as conversational speech), or rock music at a much softer volume, 25dB (not quite as loud as a quiet bedroom at night) will increase your efficiency in image recognition. The lesson here is that if you choose to listen to rock music, you should listen to it very quietly if you are engaged in a task that requires visual input–otherwise you can impair your task performance. If you choose to listen to classical music, you can listen to it at a more normal volume and it will improve your task performance.