Well educated isn't so clearly defined: In general, though, it is having been exposed to a varying number of subjects, be able to read a varying amount of things, have enough general knowledge that they can understand the reason there are "chemicals" in food and the reasons not to mix some household chemicals together. In addition, the person has been able to dive into a particular subject more deeply than the other ones, and understand that other folks have different specialties. While doing this, you are generally exposed to an array of people and if your institutions are fair, they come from mixed backgrounds.
Realistically, the basic information will be similar (basic science, health, reading, history, and so on) but we'll have different areas of interest and skill, so the exact subjects will be individualized to an extent and will definitely change over time as the world changes. You can't say for certain that psychology will make you better educated, but an introduction to the basic field might open someone's mind to being educated in that field, which helps society at large. Other things will be more esoteric: Go to art school, work in retail, and happily make art doesn't have the same sort of immediate payback - but chances are, they are more likely to be a bit compassionate just by having the education.