One thing I have noticed by spending time in and around academia is a certain predisposition of personalities within broad sets of majors and fields. This isn't to say you can say all biology majors are going to be x or y, since that is a fallacy of composition, but in general I have noticed features shared in common among those in a given grouping of majors.
Stem includes a few major separations with large gray areas. Firstly I would say you have the theoreticians. These are those whose work differs from philosophy only in how rigorous the work actually is. They use the rules of logic to build complex sets of algorithms that can be used by other fields but are often sought for their own sake. People such as mathematicians and many computer scientists spend most of their time thinking abstractly, separated from the physical world's ills and limitations. They seek relationships and algorithms and create frameworks necessary for the rest of science to work.
These individuals, in my experience both in person and reading the things they write, seem to be intelligent and very good at abstract thinking. They can construct beautiful algorithms and see relationships between things that most would never think of, much less be able to describe. The downside to such abstract thought, however, seems to be a certain affinity for abstracting reality a bit too far. To these people the relationships can take on meaning of their own accord, regardless of any application or evidence. They buy into crank hypothesis with little to no real world backing, like mind uploading and the AI singularity. Mathematicians sometimes like to think their pet numerical relationship has meaning beyond the numbers, despite evidence to the contrary. Logicians and rationalists, this group sometimes likes to over simplify the world into an abstract algorithm, since most of what they do is abstract and give general cases for things. They end up thinking they can use logic with no premises to describe all of reality.
The opposite end of these rationalists are the pragmatists who strongly populate the fields of engineering. Studies have shown that those who have engineering degrees are more conservative than the general populace and far more so than those in the other STEM fields. It is now established that conservatism tends to bear a strong relationship to mental inelasticity and it is easy to see the attraction to a field where much of the work done is the application of established theories. The grunt level of engineering is the reapplication of the same formula over and over again, allowing problem solving without genuinely abstract thought or rational analysis. Conservatives shy from abstract thinking, having a sort of mental laziness or fear of over complex ideas. The natural inclination towards shying from analytical thought may may intelligent but conservative people go into engineering. This way they can avoid anything which could upset their world view or cause them to doubt the simplistic mental constructs they build but still be challenged with problem solving.
The third group could just be called the scientists. This includes, of course, physicists and biologists but it also includes applied mathematicians and computer scientists and research engineers. The main feature of this group is the ability to think abstractly and question everything, something strongly lacking in many engineers, and the grounding in reality necessary to reevaluate their algorithms and hypothesis. These scientists must be willing to experiment and observe, to include new evidence into old abstractions and to discard said abstractions when necessary. Scientists may not lay the groundwork for rational analysis but they are capable of it. This group makes all the discoveries in nature and tends to be the most progressive and self analytical, since having something you work on for years be discarded can give you a fairly flexible outlook on life.
The logicians and theoreticians make it possible to analyze. The scientists use those tools to discover the world. The engineers get shit done, making the tools for the scientists and creating the civilization around us. Many people are in two or even three of these groups, and they are the best balanced, mentally. Abstract thought is good for us all, but practical reason is a necessary temper to it. The ability to apply our discoveries is the basis of all we have built, but being able to think critically is just as urgent. Ideally scientists could learn from engineers and logicians from scientists, and engineers could apply the reason of scientists and logicians.