Art expresses the artist’s values. When we see or hear art, we are exposed to those values. Those values are expressed in the colours, movements, shapes, words, sounds, choice of subject matter, etc. Everything in the work of art is chosen by the artist, it is not there by mistake or accident (usually!). What guides the artist’s choice? His or her value system, or system of ethics.
Art affects us emotionally, but also cognitively. Usually, we are aware of our emotional response, but not always aware of our cognitive response.
This is why art is used in propaganda: it is so powerful because it affects people emotionally. Perhaps this is a good reason to teach art in schools: so that young people can learn to not only respond emotionally to art but also consider it cognitively (by thinking).
Finally, Rand considered herself a Romantic (with a capital “R”!), rather than a Realist or Naturalist, and she shared many characteristics with other, earlier, Romantic artists, for example, an admiration for the artistic, energetic individual who is unique and intelligent and creative and free. However, most Romantic artists in the 19th century were against the intellect and logic and preferred emotion and feeling and intuition. In this respect, Rand differed from the Romantics.
The 19th century Romantics were reacting against the earlier Classicism; Rand’s Romanticism was a reaction against the Realism and Naturalism that dominated in the 20th century.