Before we go any further, we'd better look at the INTP/INTJ dilemma. One question that many struggle with is, “Am I an INTP or an INTJ?” Even type practitioners themselves can be uncertain of their own type in this regard.
Type INTJ is the type which most resembles INTP. The resemblance is not merely superficial, but actually includes deeply held values.
However, many categorize INTPs and ISTPs together on the basis of cognitive function theory. In practice this supposed INTP/ISTP resemblance just doesn’t hold up. ISTPs do not walk around with their nose in a book; they are out experiencing life for themselves. ISTPs don’t scribble mathematical equations on napkins; they’re enjoying the meal. ISTPs aren’t so lost in thought that they missed the bus; they’re already halfway to wherever they were going. But INTJs and INTPs will do all of these things.
For those of you who skipped the Preface, here is a brief summary of why the cognitive functions are not much good for differentiating between INTPs and INTJs.
A recent study53 set out to determine what exactly each of the cognitive functions consisted of—i.e. the researchers set out to determine a standard, agreed-upon definition of each cognitive function. To do this, they collected 152 descriptive words and phrases used in type literature to describe each cognitive function and its attitude (i.e. thinking introverted, thinking extraverted, intuition introverted, intuition extraverted, etc.). 31 type experts—authors, practitioners, trainers--were called in to review the list and decide which descriptors fit each of the eight function-attitudes.
The experts rated each descriptor's applicability to each function-attitude on a 1 to 5 scale. For 72 of the 152 descriptors, there was an expert consensus that a descriptor primarily matched a unique function attitude. For the rest of the descriptors, it was found that experts tended to assign the descriptors equally to two or more attitudes, or else didn't agree on any particular function-attitude at all.
So, how does this apply to type INTP? The INTP/ISTP dominant is believed to be introverted thinking, and 12 descriptors were found that primarily matched Ti.54 The list was as follows: aloof, cold, desires internal logic, detached, in-depth concentration, independent, individualistic, likes mental models, overcomplexifies, pure intellectual, research-minded, and unique use of logic.
So, do these 12 descriptors fit type INTP, as would be expected since Ti is believed to be the INTP's dominant function?
Yes. As nearly as I can tell, all 12 descriptors match both INTPs and INTJs equally well, but only five of the descriptors apply to type ISTP (aloof, cold, desires internal logic, independent, and
individualistic). Ti is not the dominant of INTJs, yet the descriptors of Ti seem to fit both INTJs and INTPs to a tee. Ti is the dominant of ISTPs, yet the descriptors do not seem to fit type ISTP very well at all. As for Ni, the dominant of INTJs and INFJs, well. The experts agreed on only two descriptors:
“Mystical” and “Trusts the unconscious.” Both descriptors had secondary matches with Fi, Ne, and Fe.
The descriptors for Ni clearly do not match the INTJ personality very well. Yet Ni, not Ti, is believed to be the dominant of the INTJ.
53 McPeek & Martin, 2012a; McPeek & Martin, 2012b
54 However, out of these 12 descriptors, it was found that five secondarily matched Te, plain N, and Ni. In short, the experts thought that those five descriptors mainly matched Ti, but also secondarily matched Te, N, and Ni.
What can we say about this? Even if one accepts that the cognitive functions exist, the murkiness and paucity of these descriptors must give one pause. There would seem to be little use in trying to use the cognitive functions to tell INTPs apart from INTJs.
Here is a list of other characteristics that can be helpful in differentiating INTPs from INTJs.
Judging vs. Perceiving (General)
• INTJs like following a regular schedule. INTPs aren't interested in having a routine.
• INTJs tend to have neat rooms, cars, and desks. INTPs tend to have messy rooms, cars, and desks.
• INTJs like clear structure more than INTPs. Indeed, INTPs are the least enthralled with clear structure of all types.55
• INTJs tend to make a plan and then follow it through. INTPs would rather just figure it out as they go along. If INTPs make a plan, they are more willing to change it on a whim or as the situation fluctuates.
• INTJs are more persevering; INTPs are more flexible.
• INTJs are better at preparing in advance; INTPs are better at improvising on the spot.
• INTJs like to come to decisions quickly and seek closure; INTPs tend to leave their options open as long as possible so that they can gather information.
• INTJs tend to put work before play; INTPs tend to put play before work.
• INTJs tend to believe that there is a right way and a wrong way to do things (i.e. there is one right way to fold shirts or one correct sequence to clean the living room) while INTPs may tend neither to care about nor notice any particular method or sequence.56
• INTJs hold onto their conclusions more strongly than INTPs. INTPs are less certain about their conclusions and more open to new data that may overturn them.
• INTJs tend to be naturally punctual; INTPs tend to be naturally late.
• INTJs get started early; INTPs wait to start.
• INTJs tend to make statements of opinion, i.e. "I think, I like, I dislike." INTPs tend to make open-ended statements that imply, but do not directly show, their opinion. INTJ: "The economy needs to be fixed." INTP: "The economy is in bad shape." INTJ: "They should change the timing on this stoplight." INTP: "This stoplight sure has weird timing.”57
• INTJs sound more confident than INTPs in their speech.
• INTJs tend to phrase their commands as direct orders, i.e. "Do this, go there, do not do this."
INTPs tend to phrase their commands as implied suggestions, "This needs to be done, can you head over there?, I wouldn't do that if I were you." INTJs give directives, while INTPs give information.58
• INTJs tend to put regular amounts of time in each day on a project; INTPs tend to work in sporadic bursts of energy with one giant effort right before the looming deadline.
• INTJs don't like surprises; INTPs do.
• INTJs use and complete to-do lists; INTPs make to-do lists but may not ever finish them.
55 Myers, McCaulley, Quenk & Hammer, 1998 56 Kroeger & Thuesen, 1994
57 Kroeger & Thuesen, 1994 58 Keirsey, 1987
• INTJs feel compelled to finish what they start; INTPs don’t mind leaving things half complete.
• INTJs tend to dress more neatly than INTPs, but both types will dress unfashionably.
• INTJs are less playful than INTPs.59
• INTJs have a higher need for control than INTPs.
Various
• INTJs excel at creating elaborate plans with timelines more than INTPs do; INTPs excel at organizing timeless systems more than INTJs do.60
• INTJs are more likely to carry their ideas out in the real world. INTPs are content simply to come up with an idea and work out the design; they do not necessarily feel the need to carry it out. They are, however, more likely to be hands-on inventors than INTJs.
• Associated with the item above, INTJs are seen as more hardworking than INTPs.
• INTJs seem more “cool”61 or less “nice” than INTPs. The impassive, unblinking INTJ “stare”
is more penetrating and discomfiting than the equivalent INTP stare.
• INTJs are less creative than INTPs.62
• INTJs tend not to be very stressed out about their children, whereas INTPs tend to be stressed out about their children.63
Stress, Sickness, Bad Habits
• INTJs don’t get (mis)diagnosed with personality disorders as often as INTPs.64
• INTJs are much less likely to smoke than INTPs.65
• INTJs have more coping mechanisms than INTPs.66
• As a result of combat, INTJs are more likely to develop major depression, while INTPs are more likely to develop Post Traumatic Stress Disorder.67
Jobs
• If you are typically dissatisfied with your job and tend to job hop a lot, then you are probably an INTP. INTPs are much less satisfied with their jobs than INTJs.68
• If you like and are confident in your ability to work with your hands, do outdoor work, do maintenance, perform construction, etc., then you are more likely to be an INTP than an INTJ.69
• If you are performing a job that entails the appreciation, consumption, or critique of art, literature, dance, poetry, etc., then you are more likely to be an INTP than an INTJ. If you are performing a job that involves analysis, problem solving, and research, then you are more likely to be an INTJ than an INTP.70
59 Myers, McCaulley, Quenk & Hammer, 1998 60 Keirsey, 1998a
61 Tieger & Barron-Tieger, 2000 62 Cheng, 2007
63 Myers, McCaulley, Quenk & Hammer, 1998 64 Coolidge, Segal, Hook, Yamazaki & Ellet, 2001 65 O'Toole, 1999
66 Hammer in Myers, McCaulley, Quenk & Hammer, 1998 67 Otis and Louks, 1997
68 Myers, McCaulley, Quenk & Hammer, 1998 69 Myers, McCaulley, Quenk & Hammer, 1998 70 Myers, McCaulley, Quenk & Hammer, 1998
• INTJs are much more likely to be found in a leadership role than INTPs.
Values
• INTPs place a higher value on autonomy than INTJs. INTJs place a higher value on achievement than INTPs.71
• INTPs place a higher value on friendships than INTJs and tend to enjoy them more.72 School73
• INTJs enjoy school more than INTPs.
• INTJs tend to get better grades than INTPs.
• INTPs tend to find school highly stressful; INTJs tend to find school highly unstressful.
Recreation74
• INTPs tend to view writing as a fun leisure pastime; INTJs do not.
• INTPs are slightly more likely to enjoy appreciating art than INTJs.
• INTJs enjoy exercising more than average; INTPs can take it or leave it.
• INTJs are less likely than average to watch 3 or more hours of TV per day. INTPs are average in this respect.
Religion75
• INTJs are about twice as likely to be atheistic as INTPs.
• INTJs are a bit more likely to be atheistic than agnostic; INTPs are a bit more likely to be agnostic than atheistic.
Areas That Are Too Similar to be Used as Diagnostic Criteria
• Marital satisfaction.76
• I.Q.77
• Argumentativeness78
• Love for computer gaming79
• Both INTJs and INTPs are confident in their ability to perform 1.) jobs that involve analysis, problem solving, and research and 2.) jobs that involve office work, performing work on a computer, accounting, filing, etc.80
• Both types have nearly the same likelihood of developing heart disease and hypertension.81
71 Myers, McCaulley, Quenk & Hammer, 1998 72 Myers, McCaulley, Quenk & Hammer, 1998 73 Myers, McCaulley, Quenk & Hammer, 1998 74 Myers, McCaulley, Quenk & Hammer, 1998 75 Myers, McCaulley, Quenk & Hammer, 1998 76 Myers, McCaulley, Quenk & Hammer, 1998
77 McCaulley & Kainz; McCaulley & Natter; Myers & McCaulley in Myers, McCaulley, Quenk & Hammer, 1998 78 Loffredo & Opt, 2006
79 Myers, McCaulley, Quenk & Hammer, 1998 80 Myers, McCaulley, Quenk & Hammer, 1998 81 Myers, McCaulley, Quenk & Hammer, 1998
I Still Don’t Know My Type
The INTP/INTJ confusion is exacerbated when nurture has heavily modified nature, or when the person in question sits riiiiight on the line between J and P.
If you still aren’t certain what type you are--and you really care--then you should probably just hack up the money and take the MBTI. (I’m serious, you can’t trust those internet tests. The authors have not done studies on whether their test is affected by gender or cultural bias; nor have they done studies to verify whether the test is producing accurate results. Then too, they haven’t attempted specifically to address the issue of people who sit on the line. The MBTI, on the other hand, has carefully addressed all of these areas over the course of several versions.)
Make sure that the testing organization will provide you with your continuous scores, i.e. whether you are a very clear or very slight Perceiver. If you have are confused about whether you are an INTP or an INTJ, then chances are you have a very slight P or J. Once you have your continuous scores, then you can verify for yourself exactly how close you are to the middle.
If it turns out that you are a middle-of-the-roader, there is a special version of the MBTI test (called the MBTI Step II) which has been specially designed to disambiguate uncertain type. It also demonstrates exactly how a person is different from the “standard model” of their type, i.e. a person may have five out of the six usual “facets” (characteristics) of Extraversion, but behave like an Introvert in one particular area.
If after all this, you still don’t know your type, don’t despair! There are good things about being both an INTP or an INTJ. You may have to reflect on the matter for awhile, but eventually it will probably become clear to you. If not, then maybe you’re simply an INTX middle-of-the-roader, a position which comes with its own advantages. Middle-of-the-roaders enjoy “amphibian” benefits because they are able to straddle the boundary between land and water and enjoy the skills of both sides. People with slight preferences are favored to succeed in situations where frequent flipflop between preferences is necessary, or when success hinges on a good balance of skills. However, just as a frog cannot swim as well as a fish nor run as well as a horse, so a middle-of-the-roader is not as favored for success in situations where one preference is consistently or strongly required; rather, those with clear preferences are favored. So, having a slight or clear preference is neither good nor bad; it merely indicates which unique ecologic niche you operate best in. And since there are all kinds of niches in this world, all kinds of preference strengths are necessary to keep things running.