Psychologists, sociologists, and anthropologists study humor because it is a fundamental cultural value, but they still cannot determine why certain things make some people laugh and others not . There are "humor quotient" tests designed to measure an individual's sense of humor, but these tests are questionable. These tests are not accurate because almost all humor depends on cultural knowledge and language skills. Not all people in the entire world, or even in a given country, share the same knowledge and skills, so they cannot have the same type of humor. “The fact remains that individuals vary in their appreciation of humor” (Rappoport 9). Since humor varies from individual to individual, the humor lies within the individual. The success or humor of a joke depends on how the person receives the joke. Humor cannot be measured by a statistic.