Belief in these supernatural entities fills the minds of the locals. As the tale tells us early on:

They are given to all kinds of marvelous beliefs; are subject to trances and visions; and frequently see strange sights, and hear music and voices in the air. The whole neighborhood abounds with local tales, haunted spots, and twilight superstitions...

Into this valley beset with superstition comes the new schoolteacher, an odd-looking man named Ichabod Crane. Besides playing with the children, helping local farmers, and singing with the church choir, he likes to go off by himself sometimes and read until the evening dusk has settled so that it is hard for him to see. At this time he walks back to whatever farmhouse he is at the time residing. However, Irving describes Crane's weakness:

His appetite for the marvelous, and his powers of digesting it, were equally extraordinary; and both had been increased by his residence in this spellbound region.

In other words, Crane is susceptible to supernatural stories and influences, and living in Sleepy Hollow has made him even more sensitive to them. As he walks home in the darkness after his reading sessions, he imagines ghostly sources for natural sounds around him of whip-poor-wills, tree-toads, screech-owls, and flocks of birds. He is startled by the sight of fireflies and the shadows of beetles. His walks home are very frightening experiences. He attempts to alleviate his fears by singing psalm tunes out loud, but these walks leave him even more vulnerable to terror later on when, on the way home from Van Tassel's party, he believes he sees the ghost of the headless horseman.

After school got out Ichabod would sometimes read all afternoon until he could no longer see the words printed in his book. When he could no longer see he would begin to make his way home. ". . . every sound of nature, at that witching  hour, fluttered his excited imagination." He would allow his imagination to run away with him so much so that at hearing these sounds (the whip-poor-will, the tree toads, the screech owl, and frightened birds) he would become frightened. He was so frightened that he was "ready to give up the ghost with the idea that he was struck with a witch's token" or that he would almost die with fright and think a curse had been laid upon him. In order to frighten evil spirits and his fears away he could often be heard by the citizens of Sleepy Hollow, singing "pslam tunes" on his walk home.