Psychologists, sociologists, and anthropologists study humor because it is a fundamental cultural value, but they still can't determine why certain things make some people laugh and others don't. 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 knowledge of cultural background and language skills. Not all people around the world, or even in one country, share the same knowledge and skills, so they may not have the same kind of humor. “The fact remains that individuals vary in their appreciation of humor” (Rappoport 9). Since humor varies from individual to individual, humor resides in the individual. The success or enjoyment of a joke depends on how the person receives it, humor cannot be measured statistically