The ISTJ and INTJ are similar in so many ways. These personalities appreciate introverted periods of alone time, use their heads instead of their hearts to make Thinking decisions, and like planning and structure to stabilize their daily Judging lifestyle.

The difference between them lies in the way they handle incoming information.

The Sensing personality collects incoming data based on his five senses, viewing everything around him in a concrete, immediate way. An Intuitive personality gathers the same data as larger fields of patterns and ramifications. They both then process the data in similar ways, using their Thinking mode to make decisions based on the data and Judging dimension to structure it into their lives.

How can you tell the ISTJ and the INTJ apart? Let’s take them on an imaginary scenario so you can identify the significant differences between them and tell who is which.

An ISTJ and INTJ walk into a bar

Let’s say that our two personalities have never been to a bar before. There’s a first time for everything. Of course, you had to promise these two friends of yours that it would be mostly empty. A Thursday Happy Hour. They agreed because it seemed like a fairly risk-free way to try something new. Curious, aloof, and hoping they dressed appropriately, they follow you up to the door. Simply accompanying them into the room will produce immediate differences between the two personalities.

Ask the Sensor what he sees and he may point out that the walls are smudged, the bartender is laughing too loud, the lighting is not up to code, and the faint scent of bleach is about to trigger an allergy attack.

The Intuitive will tell you that the bar is outdated, the bartender seems to enjoy working there, the mood lighting is actually depressing, and it’s a good thing they’ve bleached the floors because there’s a rat problem in here.

Sensors take in the details, comparing them one by one against anything they have in their memory so they can decide what it is. A bar, he thinks, is like a kitchen. It’s like a restaurant. It’s like a musty, old apartment building. He continues to hold up past experiences until he finds the closest match, at which point, he will have to add and overlay uniquely new experiences in order to form a clear picture (and memory) of what a bar is.

Intuitives take in a bigger picture and run an internal commentary on why the things in the room are presenting the way they are. With a fresh coat of paint and a lightbulb change, he thinks, this room could be inviting and fresh. He recognizes the efforts at sanitization, so he thinks there’s hope. The enthusiastic employee boosts him in his efforts to formulate what a bar could be.

Sensors take in the “what” they are seeing and Intuitives take it in through their filter of “why.” Both ways end with a “therefore.”

An ISTJ and INTJ sit down at the bar

The Sensor puts his hands into his pockets and leans back on his heels. “Now,” he thinks, “what can go wrong?” Although you’ve explained it in great detail ahead of time, he has no past experiences to help him navigate what might happen if he goes and sits down at the bar. He’s suspicious and full of the underlying stress of the great unknown.

Like most people, the Sensor hates being embarrassed. Because the situation is new, it is likely he will make a mistake at some point. Knowing that mistakes are part of the learning curve does nothing to relieve the tension. Your Sensor friend is thirsty, though, so he sits down beside you, bracing for whatever comes next and ready to get it over with.

The Intuitive puts his hands on his hips and leans forward. “Now,” he thinks, “what might happen next?” He scans the room, looking for patterns. Anything that might give him enough clues to extrapolate what might happen if you sit down at a bar. People are leaving empty glasses on the bar when they leave. Only a couple left a tip next to their empty glass. Everyone is making eye contact with the bartender, but not necessarily smiling. He’s taken in enough data to release what is not likely to happen and focus on only a handful of probable outcomes.

No one is brawling and breaking chairs and there aren’t any rats scurrying around corners. Your Intuitive friend is thirsty, too, and he doesn’t mind fumbling through some personal learning blunders, but if there’s a fight brewing in the back corner, he is very capable of ignoring his thirst and leaving now.

Sensors lean on the past as they move forward, and Intuitives lean on the future.

An ISTJ and INTJ order a drink

“What’ll you have?” the bartender asks.

The ISTJ asks for your advice. He wants something as familiar as possible although he’s never tasted alcohol. The Long Island Iced Tea on the menu does not contain tea. He’s done his homework ahead of time. He knows the alcohol content and can recite some of the cocktail recipes, but none of it can tell him whether he will like the flavor.

You advise against his idea to sample everything and find out. Even ordering a flight of beer requires choosing beer instead of everything else on the menu. Since he had an unpleasant experience in his childhood with an uncle with beer breath, the ISTJ decides he doesn’t like beer. Explaining that it doesn’t work that way changes nothing about his decision.

The ISTJ’s immediate sensing situation feels like stepping out into thin air. The INTJ has a bit more trust that there are navigational markers to cling to and looks for them.

The INTJ has been listening and making a plan. He’s observed that most of the people at this bar ordered beer and asks the bartender what the best one is. What type of beer? Seriously? He enthusiastically orders whatever the most popular one is. Safety in numbers is his strategy. He resolves that the worst that can happen is that he leaves the drink half-finished and tries a different drink some other day.

The ISTJ continues to dither because—according to his immediate senses—the worst that can happen is having to finish a drink that tastes like gasoline. That’s what you do at bars, at least from what movies and television shows tell him: you drink what’s put in front of you with a smile on your face.

ISTJs are going to follow traditions, especially if they seem to work and make everyone happy. INTJs are okay with making up their own because they always project the present senses into future senses, and the details between them matter less.

The ENFP bartender loves his job. He wants you all to be happy. He gives the ISTJ a Rum and Coke.

“On the house.”

Jolie Tunnell
Jolie Tunnell is an author, freelance writer and blogger with a background in administration and education. Raising a Variety Pack of kids with her husband, she serves up hard-won wisdom with humor, compassion and insight. Jolie is an ISTJ and lives in San Diego, California where she writes historical mysteries. Visit her at