Final answer:
The doctrine of socialist realism required composers to create works that were optimistic, uplifting, and accessible, with a focus on promoting socialist ideals and glorifying the working class.
Step-by-step explanation:
The doctrine of socialist realism required composers to produce works that were optimistic, uplifting, and accessible. This artistic method, officially endorsed at the first Soviet Writers' Congress in 1934, was designed to be a form of truthfulness showing life moving towards socialism. It was not simply a style but a method that reflected life through the prism of the Bolshevik Revolution and aimed to educate and transform the workers in line with socialist ideals.
Composers under this doctrine were to extract basic human truths from myth and folklore, and blend these with socialist ideologies to create a new reality that is optimistic and meant for the proletariat's consumption. They were encouraged to depict an idealized society where the heroes were often the working class, such as industrial workers and farmers. These depictions served not only an artistic purpose but also a political one, as they were intended to inspire the masses and promote patriotism.