The symbolic models, which were developed especially in Europe, determined the high level of complexity of the music. The European polyphonic music is one of the results of the "marriage" between image and symbolic models in music. Other civilisations, which did not have an extensive development based on symbolic models, have created in milleniums of evolution only a simple music. Let's see in the following some elements of the evolution of music in Europe. The symbolic 'recipes' appeared in music composition in the time of J.S. Bach. The maximum complexity of the music was attained during the times of W.A. Mozart. In that period, the music had several simultaneous musical lines, which, according to possibilities, were followed by those who were able to do it. E.g. in the "Great Messa", KV 427 by Mozart, several musical planes exist, which have to be followed simultaneously. Even nowadays, just the recording of this work poses technical problems. This musical work is one of the peak complexity constructions in music. Approximately after year 1800, due to the increased capacity to operate with symbolic models, the capacity to operate image models decreased. Music continued to be polyphonic, but became simpler, with a single melodic line (L. van Beethoven, contemporary with Mozart). This simplified music was called romantic music, and was a form of fundamentalism. The majority of the population lost their capacity to operate very complex image models, and so, such a simplified music was generated. This tendency continued with the increase of the limits of predictions acceptability, due the increase of the capability of construction and operation with symbolic models. E.g. the music composed by Igor Stravinsky. When his music appeared, it was rejected due to surpassing the limits of acceptability. But, in a short time, other musicians and people accepted his music, as a consequence of the increase of the acceptability limits. It is reminded that the increase of the acceptability limits is due to the increase of the capacity to build generation algorithms. An assumption is that these algorithms are supported by symbolic models. Nowadays, music is so "advanced" that it contains just a rudimentary rhythm, and an endless text (hip-hop or rap music e.g.). The children of our times have a reduced capacity to understand music. Around the year 1800, some 4 years old children were able to play the piano or violin, or even to compose music. In our days, this is not met anymore. But, some children are able to build and operate computer-based symbolic models.