10 Things to Know About the Myers-Briggs Type Indicator

The Myers-Briggs Type Indicator, or MBTI, is a popular personality test that claims to differentiate 16 distinct personality types, distinguishing the extroverts from the introverts, the sensing from the intuitive, the thinkers from the feelers, and the judgers from the perceivers. Though widely criticized by professional psychologists as pseudoscience, the MBTI is still beloved by HR departments and career counselors around the globe. Here’s some background.

1. The test was the brainchild of a mother-daughter team.

Katharine Cook (married name Briggs) was born in 1875 and went to college at the age of 14, where she studied agriculture and graduated first in her class. While Briggs was expected to live as a traditional homemaker after receiving her diploma, her desire to learn remained unquenchable. She'd pour much of her energy into educating her daughter, Isabel—who, as an adult, would later help her develop the famous test.

2. For Katharine Cook Briggs, childrearing sparked a passion for psychology.

Briggs was fascinated with the “correct” way to raise a child. She began studying developmental psychology, largely kept her daughter out of traditional school, and kept a detailed diary of Isabel's developmental progress. (Briggs referred to her living room a “cosmic laboratory of baby training.”) In the meantime, she wrote about child psychology in popular magazines like The New Republic and Ladies' Homes Journal, usually writing under the pseudonym “Elizabeth Childe.”

3. Briggs began making personality tests after meeting her future son-in-law.

When a grown-up Isabel began attending Swarthmore College, she met a law student named Clarence “Chief” Myers. They two began dating and, eventually, Isabel brought Myers home over Christmas to meet her parents. The young man perplexed Katharine—his personality was so different from everybody else in their family—and she wanted to figure out why. Briggs visited the Library of Congress and began studying the psychology of personalities.

4. Carl Jung's work had a major influence on Briggs.

Everything changed after Briggs discovered Carl Jung’s 1921 book, Psychological Types. Simplified, Jung argues that human consciousness has two perceiving "function-types" (sensation and intuition) and two judging "function-types" (thinking and feeling), which are moderated by a person’s introversion or extraversion. Briggs was so fascinated by Jung’s theories that she began calling his book "The Bible" and wrote him fan mail. In 1926, she published an article in The New Republic distilling his theories into a sort of paint-by-numbers exercise entitled, “Meet Yourself: How to Use the Personality Paint Box.”

5. Isabel’s disillusionment with temp work turned her into an apostle of her mother's work.

Katharine Briggs and Isabel Briggs-Myers
Katharine Briggs and Isabel Briggs-Myers
Katharine Myers, Public Domain, Wikimedia Commons

One summer, Isabel Briggs Myers (she married "Chief" in 1918) landed an unfulfilling job at a temp agency. She later gave it up for housework, but found homemaking just as lackluster an occupation. In a letter to her mother, Myers expressed a wish for “some highly intelligent division of labor that can be worked out, so everybody works, but not at the wrong things.” (She’d eventually find satisfaction as an author, later writing a detective novel called Murder Yet to Come, which won a $7500 magazine writing contest.) Her preoccupation with finding the right work, however, boosted Isabel's interest in her mother’s research.

6. The First Myers-Briggs test was originally focused on the WWII job market.

With the adoption of the GI Bill and a new influx of working women, World War II saw the American labor force blossom. It was a boon for career consultants, too, who were seeking standardized tests that could sort all of these new workers into their ideal jobs. According to Merve Emre, author of The Personality Brokers, a slew of tests were, “made under the watchful eyes of executives eager to keep both profits and morale high.” Myers would adapt and pitch her mother’s personality tests to a consultant named Edward N. Hay, arguing that they could help people entering the workforce find their career match. Hay loved the idea.

7. The test gained popularity as a way tool for hiring—and firing—employees.

Hay pitched the test to his biggest clients: General Electric, Standard Oil, Bell Telephone, and officials in the U.S. Army. Corporate honchos were quickly convinced that, by directing the right people to the right jobs, the test could help reduce turnover. According to Emre, Myers-Briggs encouraged employers to “reassign or fire people” according to their personality types. (At an electric company, for example, introverts could be assigned clerical work while extroverts were sent out to read meters.)

8. It’s not based on any formal psychology.

One concern with the MBTI is that nobody involved in developing it had any formal education in psychology or psychometrics (the study how to objectively measure psychological traits). Briggs, a devoted autodidact, would say, “One need not be a psychologist in order to collect and identify types any more than one needs to be a botanist to collect and identify plants.” Her critics, however, disagreed.

9. The MBTI is statistically unreliable.

The Myers-Briggs indicator suffers from “low test reliability.” That is: If you take the test more than twice, there’s a good chance you’ll be classified as a different personality type. “If you retake the test after only a five-week gap, there's around a 50 percent chance that you will fall into a different personality category compared to the first time you took the test,” the philosopher Roman Krznaric wrote for Fortune. As a scientific metric, the test is consistently unreliable.

10. Professional psychologists have described the test as a "fortune cookie."

Researchers have described the MBTI as “an act of irresponsible armchair philosophy” and a “Jungian horoscope.” Critics argue that the mother-daughter team misread Jung’s work on types. (Indeed, Jung himself said that slapping personality labels onto people was “nothing but a childish parlor game.”) In the early 1990s, a U.S. Army Research Institute commissioned study concluded, “At this time, there is not sufficient, well-designed research to justify the use of the MBTI in career counseling programs" [PDF] and the psychometric expert Robert Hogan said that, "Most personality psychologists regard the MBTI as little more than an elaborate Chinese fortune cookie." Despite the criticism, the test is still used by a majority of Fortune 100 companies—all to the tune of $20 million a year.

This $49 Video Game Design Course Will Teach You Everything From Coding to Digital Art Skills

EvgeniyShkolenko/iStock via Getty Images
EvgeniyShkolenko/iStock via Getty Images

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10 Secrets of Ice Cream Truck Drivers

asiafoto/iStock via Getty Images Plus
asiafoto/iStock via Getty Images Plus

Ever since Good Humor founder Harry Burt dispatched the first jingling ice cream trucks in Youngstown, Ohio, in 1920, kids and adults alike have had a primal reaction to the sight of a vehicle equipped with a cold, sugary payload. Today, ice cream trucks spend May through October hoping to entice customers into making an impulse beat-the-heat purchase. To get a better idea of what goes into making ice cream a portable business, Mental Floss spoke with several proprietors for their take on everything from ideal weather conditions to police encounters. Here’s the inside scoop.


The most common misconception about the ice cream truck business? That soaring temperatures mean soaring profits. According to Jim Malin, owner of Jim’s Ice Cream Truck in Fairfield, Connecticut, record highs can mean decreased profits. “When it’s really hot, like 90 or 100 degrees out, sales go way down,” Malin says. “People aren’t outside. They’re indoors with air conditioning.” And like a lot of trucks, Malin’s isn’t equipped with air conditioning. “I’m suffering and sales are suffering." The ideal temperature? "A 75-degree day is perfect.”


An ice cream truck sits parked in a public spot
Chunky Dunks

The days of driving a few miles an hour down a residential street hoping for a hungry clientele have fallen by the wayside. Many vendors, including Malin, make up half or more of their business by arranging for scheduled stops at events like weddings, employee picnics, or school functions. “We do birthday parties, church festivals, sometimes block parties,” he says. Customers can pay in advance, meaning that all guests have to do is order from the menu.


For sheer ice cream horsepower, nothing beats a minibus. Laci Byerly, owner of Doodlebop’s Ice Cream Emporium in Jacksonville, Florida, uses an airport-style shuttle for her inventory. “Instead of one or two freezers, we can fit three,” she says. More importantly, the extra space means she doesn’t have to spend the day hunched over. “We can stand straight up.”


A picture of an ice cream truck menu.
Sarah Silbiger/Getty Images

The goal of any truck is to sell enough ice cream to justify the time and expense of operation, so freebies don’t make much sense—unless the truck happens to have some damaged goods. Malin says that it’s common for some pre-packaged bars to be broken inside wrappers, rendering them unattractive for sale. He sets these bars aside for kids who know the score. “I put them in a little box for kids who come up and ask if I have damaged ice cream,” he says. “Certain kids know I have it, and I’m happy to give it to them.”


An ice cream nacho platter is shown
Chunky Dunks

While pre-packaged Popsicles and ice cream sandwiches remain perennial sellers, a number of trucks are mixing up business by offering one-of-a-kind treats. At the Chunky Dunks truck in Madison, Mississippi, owner Will Lamkin serves up Ice Cream Nachos, a signature dish that outsells anything made by Nestle. “It’s cinnamon sugar chips with your choice of ice cream,” he says. “You get whipped cream, too. And for the ‘cheese,’ it’s a caramel-chocolate sauce.” The nachos work because they’re “streetable,” Lamkin’s label for something people can carry while walking. “The next seven or eight people in line see it, and then everyone’s ordering it.”


Before most people see an ice cream truck, they hear that familiar tinny tune. While some operators still rely on it for its familiarity, Malin and others prefer more modern tracks. “Normally we play ‘80s rock,” he says. “Or whatever we feel like playing that day. We rock it out.”


A Captain America ice cream treat

While adult customers tend to favor ice cream treats they remember from their youth, kids who don’t really recognize nostalgia tend to like items emblazoned with the likenesses and trademarks of licensed characters currently occupying their TV screens and local theaters. “Characters are the most popular with kids,” Byerly says. “SpongeBob, Minions, and Captain America.”


At Doodlebop’s, Byerly has a strategy for luring customers with pets: She keeps dog treats on hand. “The dog will sometimes get to us before the owner does,” she says. “If the dog comes up to the truck, he’ll get a Milkbone.” That often leads to a human companion purchasing a treat for themselves.


Though there have been stories of rogue ice cream vendors aggressively competing for neighborhood space over the years, Malin says that he’s never experienced any kind of out-and-out turf war. Ice cream truck drivers tend to be a little more passive-aggressive than that. “I have a business permit for Fairfield, so that’s typically where I’m driving,” he says. “But sometimes I might go out of town for an event. Once, a driver pulled up to me and asked if I had a permit. I said ‘No, I’m just here for an hour,’ and he said, ‘OK, I’m calling the cops.’ They try and get the police to get you out [of town].” Fortunately, police typically don’t write up drivers for the infraction.


An ice cream truck driver.
George Rose/Getty Images

Technology has influenced everything, and ice cream trucks are no exception. Malin uses an app that allows customers to request that he make a special delivery. "People can request I pull up right outside their home," he says. If their parents are home, there’s one additional perk: "I accept credit cards."

This article originally ran in 2018.