Although we often accept film music without question and sometimes even without noticing it, this does not mean that its contribution to the film experience is insignificant. Music has a tremendous effect on our response, greatly enriching and enhancing our overall reaction to almost any film. It accomplishes this in several ways: by reinforcing or strengthening the emotional content of the image, by stimulating the imagination and the kinetic sense, and by suggesting and expressing emotions that cannot be conveyed by pictorial means alone.

Because music has a direct and very significant effect on our reaction to film, the term “background music,” which is so often applied to the musical score, is a misnomer. Music actually functions as an integral or complementary element. In spite of its direct effect on us, however, there is general critical agreement that the role of music in film should be a subordinate one.

Two schools of thought exist on the proper degree of this subordination. The older, traditional view is that the best film music performs its various functions without making us consciously aware of its presence. In other words, if we do not notice the music, it is a good score. Therefore, the music for a “good” score should not be too good, for really good music draws attention to itself and away from the film.

The modern view, by contrast, allows the music, on appropriate occasions, not only to demand our conscious attention but even to dominate the picture, so long as it remains essentially integrated with the vital, dramatic, and rhythmic elements of the film as a whole. At such moments, we may become conscious of how intrinsically beautiful the music is, though we should not be so moved that we lose sight of its appropriateness to the image on the screen. Both modern and traditional views are therefore in agreement on one essential point: music that calls too much attention to itself at the expense of the film as a whole is not effective.

In the temperate climate zone, mixed-species flocks of birds are mostly a winter phenomenon, occurring after the breeding season, when territorial boundaries are no longer observed. In some wooded areas of North America, for example, chickadees, titmice, nuthatches, kinglets, brown creepers, and woodpeckers travel together in loose flocks, and while the mix is different in the tropics, the underlying principles are the same. Ecologists who have studied mixed flocks believe they offer a number of advantages over single-species aggregations—better detection of predators, for instance, combined with minimal competition owing to species-specific foraging techniques.

Every species in a mixed flock has a preferred food and a specialized hunting method. The acrobatic chickadees hang upside down from branches, peering into cracks and crevices for hibernating arthropods (small invertebrates, including insects) or egg masses, while the tiny kinglets flit and hover at the very tips of the twigs, where heavier birds cannot reach. Downy woodpeckers work their way up the trunks and nuthatches go down, headfirst, each finding food that the other missed. The creepers, like the woodpeckers, ascend the tree in a spiral, but they pay particular attention to the spaces between bark flakes, while the woodpeckers, with their sturdier bills and barbed, spearlike tongues, focus on bugs hidden deeper inside the tree trunk. Species in mixed flocks often seek the same foods, but the ways in which they look, and where they look, are different.

Mixed-species flocks reach their greatest expression in the tropics, especially in the Amazon Basin, where as many as six dozen species have been seen in a single gathering. Each flock is made up of subsets of birds, each with its own role to play. At the core is one or more “nucleus species,” as they are known, usually a mated pair or a family group; by their behavior and calls, they hold the flock together, set the pace for the group and providing cohesion. They are joined by what ecologists call attendant species, some staying with the flock almost full-time, others following for a few hours but then dropping out, and still others joining only briefly while the flock is traversing their territory.

The city of Chicago, Illinois, is renowned for its diverse collection of public artwork, which features statues, sculptures, and numerous painted wall murals. Interestingly, the creation of a large portion of these Chicago murals took place during the period of the Great Depression—an economic downturn in the 1930s characterized by high unemployment rates where about a quarter of the country's workforce lacked jobs by 1932. This development occurred because President Franklin Roosevelt formulated a comprehensive legislative initiative known as the "New Deal" in 1933 to address the crisis, with its primary objective being job creation. Consequently, the federal government emerged as a leading financial supporter of public art. Established in 1935, the Federal Art Project (FAP) operated as one of its major programs and stands as the largest initiative of its kind ever attempted. Spanning from 1935 through 1943, the FAP sponsored various projects across disciplines such as fine art, theater, music, and writing, engaging roughly 5,000 nationwide artists who collectively produced hundreds of thousands of paintings, sculptures, and murals.

Operating locally in Chicago, the Illinois division of the FAP hired hundreds of qualified yet jobless artists alongside numerous assistants to paint and decorate public structures. These muralists received instructions to center their work on American themes, connect with ordinary citizens, and portray optimism about the future. Most artists utilized a naturalistic approach rather than heavy abstraction. Out of approximately 200 murals originally created across greater Chicago, about two-thirds have managed to survive over time, with some having been painted over and slated for restoration.

Furthermore, Chicago's mural movement actually began a year prior to the launch of the FAP. In 1934, the United States Treasury Department established a decoration program for newly constructed federal buildings, particularly post offices. This program drew financial support from a small percentage of the total construction budget and selected participating artists through anonymous competitions. Modern government entities continue supporting public art for new spaces through "Percent for Art" initiatives. For instance, a program established by the city of Chicago in 1978—now designated as the Chicago Department of Cultural Affairs Public Art Program—is responsible for placing over 400 distinct works of art across local public facilities such as police stations, firehouses, libraries, and health and transportation centers.

The first peoples to inhabit what today is the southeastern United States sustained themselves as hunters and gatherers. Sometimes early in the first millennium A.D., however, they began to cultivate corn and other crops. Gradually, as they became more skilled at gardening, they settled into permanent villages and developed a rich culture, characterized by the great earthen mounds they erected as monuments to their gods and as tombs for their distinguished dead.

Most of these early mound builders were part of the Adena-Hopewell culture, which had its beginnings near the Ohio River and takes its name from sites in Ohio. The culture spread southward into the present-day states of Louisiana, Alabama, Georgia, and Florida. Its peoples became great traders, bartering jewelry, pottery, animal pelts, tools, and other goods along extensive trading networks that stretched up and down eastern North America and as far west as the Rocky Mountains.

About A.D. 400, the Hopewell culture fell into decay. Over the next centuries, it was supplanted by another culture, the Mississippian, named after the river along which many of its earliest villages were located. This complex civilization dominated the Southeast from about A.D. 700 until shortly before the Europeans began arriving in the sixteenth century.

At the peak of its strength, about the year 1200, it was the most advanced culture in North America. Like their Hopewell predecessors, the Mississippians became highly skilled at growing food, although on a grander scale. They developed an improved strain of corn, which could survive in wet soil and a relatively cool climate, and also learned to cultivate beans.

Indeed, agriculture became so important to the Mississippians that it became closely associated with the Sun – the guarantor of good crops. Many tribes called themselves "children of the Sun" and believed their omnipotent priest-chiefs were descendants of the great sun god.

Although most Mississippians lived in small villages, many others inhabited large towns. Most of these towns boasted at least one major flat-topped mound on which stood a temple that contained a sacred flame. Only priests and those charged with guarding the flame could enter the temples. The mounds also served as ceremonial and trading sites, and at times they were used as burial grounds.