This article is an excerpt from the Shortform summary of "Outliers" by Malcolm Gladwell. Shortform has the world's best summaries of books you should be reading.
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A lot of people obsess about intelligence testing and IQ tests. But why does intelligence matter? And what are the limitations of what intelligence testing can tell you?
Limitations of IQ Testing Geniuses
If outliers are people whose abilities and experiences are statistically far outside the norm, then geniuses are the ultimate outliers. We may understand that talent can only take you so far, but we place intelligence on a different plane than mere talent. We assume that the more intelligent you are, the more successful you will be.
However, just as with other personal attributes, IQ only determines success up to a certain point. After meeting the threshold of “smart enough,” differences in achievement based on IQ tend to level out.
The advantage of IQ can be likened to the advantage of height on a basketball court. A 6’3” player has a clear advantage over a player who is 5’6”. But a player who’s 6’3” and a player who’s 6’5” are probably pretty equally matched. When the height difference is so small, other factors, such as speed, agility, and strength, more heavily impact success. There are clear limitations other than height.
It turns out that their IQ does not make some geniuses outliers, although a high IQ helps. As we’ve seen in previous chapters, what truly turns someone into an outlier are the opportunities he’s offered.
The IQ Threshold
Again, it’s not that IQ is irrelevant—in order to handle college work, you probably need an IQ of just above 100 (100 is average). If you succeed in a graduate program your IQ is likely at least 115. The higher your IQ, the more money you’re likely to make and the longer you’re likely to live. It’s just that beyond a certain point (an IQ of 120), opportunity matters more.
This is called the “threshold effect”: once you hit a threshold and you’re “smart enough,” then opportunity plays a larger role in determining your success. This is a serious limitation of IQ testing.
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Here's what you'll find in our full Outliers summary :
- What makes some people outliers, and most others not
- Why some genius outliers end up failing in life
- Why Asians are good at math, and other curiosities of culture
