The GRE is designed to:
• Predict student success in business school, allowing schools to accept those most likely to be successful.
• Measure higher-order thinking abilities through quantitative reasoning and verbal reasoning.
Now, the theory behind the two scopes above from the ETS standing point is eventually based on Bloom's Taxonomy of Educational Objectives.
The Taxonomy of Educational Objectives, known as Bloom's Taxonomy (Bloom, Engelhart, Furst, & Krathwohl, 1956) is one of the most recognized learning theories in the field of education. Educators often use Bloom's Taxonomy to create learning outcomes that target not only subject matter but also the depth of learning they want students to achieve. Bloom's Taxonomy comprises three learning domains: cognitive, affective, and psychomotor, and assigns to each of these domains a hierarchy that corresponds to different levels of learning.
For our purpose, the domain of our interest is the cognitive domain. The cognitive domain is focused on intellectual skills such as critical thinking, problem-solving, and creating a knowledge base. It was the first domain created by the original group of Bloom's researchers. The cognitive hierarchy spans from simple memorization designed to build the knowledge of learners to creating something new based on previously learned information. In this domain, learners are expected to progress linearly through the hierarchy, beginning at "remember" and ending at "create."
Simply put, the GRE is a test of how you think, not what you know.The taxonomy above is still widely used in the most disparate learning environments, And it is constantly updated thanks to the contributions of scholars from every corner of knowledge: economics, psychology, human behavior, and so forth.
However, in my experience, this is enough to explain what the GRE is but not sufficient, in my humble opinion. The GRE is a niche test. It could be intended as a parallel universe in which the student is pushed to the boundaries of their critical thinking. Seein and solve questions from an old evaluation angle or point of view.
Put in simple words, the GRE is a holistic approach to problem-solving. As I pointed out several times, it is a non-zero game. Therefore we do need something that goes and push us even further.
This is a personal elaboration by the author of this guide.