Look for the person who keeps to himself and who prefers to work independently. INTPs are often shy and quiet around co-workers, until they have an interesting problem to solve. INTPs value logic, and excel at seeing theoretical possibilities. When an INTP is excited about a project, she will work tirelessly through the night to find a solution to the problem. INTPs are often spotted in career fields such as science, law, math, computer programming and engineering.

Observe the relational style. INTPs live so much in their heads that they can seem distant and aloof. You can often spot an INTP by the way he relates to others. Because INTPs are highly analytical and logical thinkers, they can find it difficult to express their feelings and understand the feelings of others. They can sometimes come across as unsupportive, critical and sarcastic. However, INTPs are incredibly loyal and enjoy straightforward, honest relationships. They love deeply and dislike drama.

INTP children are easy to spot. They're very creative, individualistic and like a lot of alone time. They can seem emotionally distant from their parents at times. INTP children are intellectually curious and ask many questions (questioning authority is a favorite pastime of INTPs). You can spot an INTP child by how mature and intellectual she seems for her age. INTP children have vivid imaginations and love fantasy.