It's not every day you have to be worried about getting outsmarted by a toddler. Then again, it's also not every day that a 2-year-old becomes Mensa's youngest member.

Isla McNabb, a young Kentucky resident with an IQ reportedly in the 99th percentile, went viral after she won acceptance into the global society of high-IQ individuals in May. Her advanced intelligence has left many people awestruck and predicting more impressive feats ahead for the precocious preschooler.

Her story begs the question: Does a child's high IQ set them up for career or financial success down the road? According to psychologist John Antonakis, the answer is essentially yes.

"[IQ is] the single most important predictor of work success," Antonakis, a professor of organizational behavior at Switzerland's University of Lausanne who focuses on leadership and management research, tells CNBC Make It. "It's a very robust and very reliable predictor."

In 2012, Vanderbilt University psychology researchers found that people with higher IQs tend to earn higher incomes, on average, than those with lower IQs. Past studies have also shown that high IQs are comparably reliable in predicting academic success, job performance, career potential and creativity.

Antonakis says high IQs are particularly notable predictors for success in highly complicated, skilled occupations like physicist, engineer or even neurosurgeon. But don't worry, he adds: You can still be highly successful without being a Mensa member. These five other skills and traits factor into your career success and overall happiness, too:

• Ability to be outgoing and friendly
• Self-confidence
• Being open to new experiences
• Organizational abilities
• Strong communication skills

Here's how it all works.

The correlation between IQ and career or academic success in school and work is "a no-brainer," Antonakis says. After all, your IQ – short for intelligence quotient – is a measurement of your ability to reason, process information and use it to solve a problem.

"The modern definition of intelligence is the ability to learn," Antonakis says. And the greater your ability to learn – to improve yourself, pick up new skills and make smart decisions – the more likely you are to perform well at work and advance your career.

But plenty of research shows that success requires more than just IQ. Being outgoing and friendly, confident, open to new experiences and well-organized are all important personality traits that can help you get ahead in life, according to psychological studies.

In other words, a lower IQ doesn't necessarily doom you to an unsuccessful or unfulfilling life, especially if you work to maximize your strongest skills and traits. "You could do another job [that] requires good social skills," Antonakis says. "If you're agreeable, and if you're extroverted, that's absolutely fine. You can still succeed."

Success can also be defined in plenty of different ways, from annual income to overall happiness – and IQ isn't quite as strong of a predictor for the latter, research says. 

High IQ may be a reliable predictor for success, but it's no guarantee. Antonakis says context matters: For instance, a person with a high IQ working in a relatively non-complex role might not thrive, simply because it doesn't interest them.

"There has to be a fit between the exigencies of the job, and the characteristics of the person who will occupy the job," Antonakis says. "So, of course, if you put a too smart person in a janitor's position, they're going to be bored, they're not going to be challenged enough."

You also have to consider how that person's work might be perceived by people who don't share their same level of intelligence. Leaders can get into trouble if their IQ is significantly higher than their team's, and employees can similarly hit roadblocks if they think they're smarter than their boss.

Antonakis's own research shows that high-IQ leaders get better results than less intelligent leaders. Perhaps unsurprisingly, a 2013 study found that Fortune 500 CEOs are typically overrepresented among the top 1%, in terms of cognitive abilities.

But, there is such a thing as being too smart, especially where perception is concerned.

"You need to be smarter. But if you're too smart, then people won't identify with you [and] they might find you too aloof," Antonakis says. "And it makes it harder to lead if the [IQ] gap between the leader and the followers is too large."

That's where communication is key. Antonakis cites highly-intelligent leaders from Barack Obama and Bill Clinton to Margaret Thatcher and Winston Churchill who used their communication skills and charisma to present complex strategies in digestible ways to win over large swaths of followers.

Researchers have described this ability as emotional intelligence, or EQ. Antonakis posits that EQ is actually a factor of IQ: If you're a smart enough leader, you'll figure out how to communicate your ideas in the most compelling way possible.

The bottom line, he says, is that the person with the highest IQ in the room might not be guaranteed the most success – but they certainly have a head start.

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