In addition to the physical elements of music previously discussed there are other factors which enter into the type of response of mind and body to music. Mention has been made above of the value of program notes. People who hear new music for the first time may or may not develop a visual or emotional response, but if prepared by descriptive writing they may “understand” or at least enjoy the music more. “Program notes, oral comments, and the general setting of the presentation are important because they concentrate and reinforce the mood response. Indeed it has been shown that in a verbal introduction offered before a composition is presented, what is said does not matter much, and that almost any kind of comment will enhance the listener’s enjoyment if it serves to cue him into appropriate effective states of mind.”[60] Music aides should take this finding seriously and preface the playing of musical selections with verbal commentary. Even popular dance music may be prefaced by remarks about the solo instrument featured or the personalities involved. With the exception of the effects of rhythm, all other reactions thus far cited have been largely psychologic. Before leaving the discussion of response, one bit of evidence demonstrating possible physiologic action will be presented. Gundlach[39] studied the songs of six different American Indian tribes. Now the language, customs and music of neighboring European countries frequently have something in common, but the absence of the wheel in transportation made the scattered people of the Western Hemisphere strangers to each other. The speech and songs of the different Indian nations are entirely unrelated, yet the songs representing the same types of ceremonials show considerable agreement. From this Gundlach concludes that “music has some conventions grounded on a firm basis of physiologic structure and behavioral similarity of human beings.”