In a study published in the journal Psychological Science, Dr. Delroy L. Paulhus explains the results of experiments designed to identify people predisposed to revel in others’ suffering—like those who cheer at sports games when people get injured. People he calls "everyday sadists." The experiments involve crushing bugs and white noise:

In the study’s first experiment, to learn if everyday sadism correlated with the questionnaire, researchers recruited 71 psychology students, ostensibly to understand “personality and tolerance for challenging jobs.”

The students chose among tasks that stood for jobs: killing bugs (exterminator); helping the exterminator (exterminator’s assistant); cleaning toilets (sanitation worker); or enduring pain from ice water (a worker in cold environments). Among the participants, nearly 53 percent chose to be bug assassins or assistants, 34 percent chose toilet-cleaning and 13 percent pain tolerance. Gender was evenly distributed among those choosing various tasks.

Students who chose to be bug-killers were presented with three cups, each holding a live pill bug. To anthropomorphize the bugs, each was given a name: Muffin, Ike, or Tootsie. Bug-killers had to drop a bug into a modified coffee grinder, force the top down, and grind the bug up.

... During the execution of the assignment, some bug-killers quit after one or two. But some asked for more bugs.

In other news, every five-year-old I know is an everyday sadist.