Smart Sounds: Fans of jazz, classical and other "complex" music typically have above-average IQ scores.

Easy Listeners: Fans of country and Top 40 hits tend to be more conventional, honest and conservative compared with fans of other genres. "People who like country and pop might be more simpleminded, and that's not necessarily bad," says [Cambridge psychologist Jason] Rentfrow. "They just avoid making things unnecessarily complex."

Drama Queens: Compared with other music fans, opera aficionados are three times more likely to endorse suicide as a solution to family dishonor, says Steven Stack, a psychologist at Wayne State University in Michigan. Don't blame Madame Butterfly. Stack says dramatic personalities are drawn to opera, not influenced by it.

Parental Advisory: Parents often worry that music—whether it's Elvis or Eminem—promotes sexual or aggressive behavior in teens. Rentfrow's work has found no direct link. In fact, fans of gangsta rap or heavy metal are often more timid and shy than other kids, he says.

Boom Town: Extroverts gravitate to music with a heavy bass line, according to a Northeast Louisiana University study.

Brain Invasion: Whether you can study or work efficiently while listening to music may depend on how outgoing you are. Background music can help extroverts focus, but tends to torment introverts.

Peak Performance: It may work for Rocky Balboa, but music doesn't always pump up athletes. Motivational music can give weightlifters an edge. Runners, however, don't move farther or faster with the help of motivational music.

Motormouths: Fans of energetic music like dance and soul are more likely to impulsively blurt out their thoughts, compared with fans of other styles.