(CNN) -- Three-year-old Alexis Martin reads at a fifth-grade level. She taught herself fluent Spanish using her parents' iPad.

"From 12 to 18 months old, we'd be driving around in the car, and she would recite her bedtime story from the night before," her dad, Ian, told CNN affiliate KNXV. "She didn't just recite them; she recited them exactly."

Alexis is the youngest member of Arizona's Mensa chapter. American Mensa (PDF) is an organization for people with IQs in the top 2%.

But what does an IQ score really tell us about a person? Will Alexis be a genius for life? And if you still can't speak Spanish at age 50, should you just give up?

An Intelligence Quotient, or IQ, is a measure of what psychologists call our "fluid and crystallized intelligence." Put simply, an IQ test measures your reasoning and problem-solving abilities.

There are different kinds of IQ tests, but most analyze your visual, mathematical and language abilities as well as your memory and information processing speed. A licensed psychologist administers a series of subtests; the results are then combined into one score: your IQ.

"Anybody with very high IQ, they have the ability to manipulate, process and interpret information at a deeper level and a higher speed than the average person," explained Mensa's gifted youth specialist, Lisa Van Gemert.

An IQ score doesn't measure your practical intelligence: knowing how to make things work, says Richard Nisbett, a professor of psychology at the University of Michigan. It doesn't measure your creativity. It doesn't measure your curiosity.

It doesn't tell your parents or teachers about your emotional readiness. Maybe as a 5-year-old, you can read and understand The Economist. But are you prepared to deal with stories about war-torn countries or prisoners on death row?

It would be a mistake, Van Gemert says, to look at a child with a high IQ as nothing more than a brain. Like any trait -- blue eyes, big feet -- their IQ is just one part of who they are.

Read the full article at http://www.cnn.com/2014/02/19/health/iq-score-meaning/index.html?hpt=hp_bn13