Back when I first started taking interest in psychology I learned about the Theory of Multiple Intelligences. An in-depth explanation can be found here, but in short, it's a theory by Robert Gardner that suggests there are up to eight different categories of intelligence that people can fall under.
While the theory itself doesn't have the strongest scientific backing, the concept behind it can help explain why people can so easily understand some ideas and struggle on others. Here's a quick breakdown of each category.
1. Logical-Mathematical
Otherwise known as the standard definition of intelligence, the logical-mathematical branch is your ability to think critically; once you get the gist of a concept or formula, it inevitably becomes second nature to you.
Sooner or later you've figured out how to put each concept into practice and even apply them to practical real life situations. People who excel in this field of intelligence are the next Albert Einsteins and Marie Curies of the world.
2. Bodily-Kinesthetic
This branch can be explained most simply as physical intelligence. This mostly deals with one's understanding of how their body functions and how to take care of it appropriately.
Those with bodily-kinesthetic intelligence are the ones who know how to get the most out of their workouts and push their bodies to the limit without going too far. Michael Phelps and Usain Bolt would probably feel at home in this category.
3. Interpersonal
The interpersonal field is essentially one's social intelligence; with this people are able to read the emotions of others and infer why they're feeling that way. Some people with this type of intelligence also know how to bring out the best (or worst) from their peers, making them effective leaders. Combine that with a knack for making the right connections, you've got the Kim Kardashians and Oprah Winfreys of the world.
4. Verbal-Linguistic
Many of these fields understand how to create ideas. Verbal-linguistic intelligence helps bring these ideas out into the open. Any writing done by verbal-linguists is concise and powerful, and their ability to eloquently voice opinions can make them appear smart in almost every aspect. All types of people can use this ability in different ways; both Martin Luther King Jr. and Adolf Hitler used their voice to lead the masses.
5. Intrapersonal
Although this may sound similar to interpersonal intelligence, intrapersonal deals solely with the understanding of one's self. These people can acknowledge their own flaws and determine how to amend them in their own unique way. Love them or hate them, those gifted with intrapersonal intelligence are in tune with their identities.
6. Visual-Spacial
The last three intelligence types are more controversial in the psychological community and can sometimes be described more accurately as a talent rather than intellect. Visual-spatial intelligence deals with one's ability to - you guessed it - visualize an idea in their mind. Artists and architects alike possess this intelligence type to some extent, and visionaries such as Pablo Picasso take it to the next level.
7. Musical-Rhythmic
This one is also self-explanatory. Musical-rhythmic intelligence determines one's sensitivity to pitch, tone and rhythm among other things. With this, dancers are able to move fluidly with the music, singers can reach pitch perfection, and rappers flow cleanly with hard hitting beats. This variation of intelligence comes in many forms, from the prodigal Wolfgang Mozart to the enthusiastic Lil Pump.
8. Naturalistic
Those with naturalistic intelligence are in tune with the world surrounding them, recognizing the different forms and uses of both plants and animals. While this may seem like the least practical form of intelligence, it actually helps quite a bit when cooking or farming, so those with a keen sense of taste fall into this field quite comfortably.
Regardless of your GPA, there's going to be at least one form of intelligence you shine in. Heck, it's likely you've already mastered multiple forms. Find which field of intelligence is right for you.