One of the main subjects of a course I took in college called Art of the Film was the use of shadows in black and white films. Shadows are placed on purpose by the directors of these films to make the audience fell uncomfortable and on edge. Often these shadows are where they shouldn't be and are even used as a foreshadow of a future occurrence in the movie.
Perhaps the best at the use of shadows was Orson Welles. Of course, he scared the whole world with his broadcast of H.G. Wells' War of the Worlds as he didn't warn anyone that it was just a broadcast, not an actual event.
His most famous film, Citizen Kane, depicts a very rich man, purported to be William Randolph Hearst. Even though he was rich and had everything he could want, he had a shadow side where he often dreamed of being a youth and sliding on snow on his sled, Rosebud. This shows his desire to return to his carefree days and to shed all these acquisitions he is now burdened with. The movie is full of shadows, odd camera angles and eerie music that helps to show his uneasiness.
Another film that Orson Welles starred and help direct was: The Third Man. This post-WWII film depicted a wolf in sheep's clothing, play by him. He was a spy who was sent to do unknown naughty things only implied by him but never actually described. It is a very scary movie without any monsters.
Many of the first films made were monster movies. Count Dracula, Frankenstein, King Kong were some of the favorite subjects. People really wanted to be scared and paid there hard-earned money to go to them. Even during the depression, there was a market for these films. There was even use of a tesla-coil in some of these movies that would shoot a bolt of lightning across a room.
One of my favorite scary movies again without monsters was the original Cape Fear. Robert Mitchum portrays a very nasty, mean man. He was perfect for the role and should have one an academy award. But, back then they only gave awards to actors playing good guys.
In the early days of television with the Alfred Hitchcock hour, The Twilight Zone and the Outer Limits there was a large amount of scary, quirky subjects. When I went to college I took a course in high energy physics and found that the actual formula was: E = mc² + p²c², with out the "p" you have a static universe with no light. Star Trek was a welcome relief for the ET world as it depicted a more user-friendly alien, Mr. Spock. He was different and look weird, but was logical.
The shadow side in paintings can be found in the expressionist paintings of Edvard Munch and others of his genre. My favorite is: The Scream.
This painting depicts a scary, ET-like being that is, of course, screaming seemingly with great fear of something. Some have suggested that this depicts a precursor to the coming world wars and the nuclear age with a UFO or two thrown in.
The shadow side for music is that at-least when my parents and grandparents were growing up, naughty music that you danced to on Saturday night (oommp pa pa). The good music was played by the organist in church the next day. Somber, non-joyous hymns were the preference in the churches on Sunday.
If you listened to Jazz or blues music you were considered to be a derelict or a drug addict. Country western was ok and some banjo playing was allowed.
Then along came Elvis and ruined the whole system. He snuck across Beale Street with some of his buddies to see Chuck Berry and some good old rock and roll. Later he got his own look and, as BB King said was even a passable singer. Now it was ok to be naughty and nice.
Then came the 60's and 70's and music became more acceptable and much more varied and fun. Now we can listen to any kind of music we want and dance til the break of dawn.