You can learn extra fields on top of most social fields but it will affect your grades. And no reading only for exam won’t work because the field by itself requires understanding rather than knowing by heart (because they are reasoning and calculation based theories). And that is easier to do if you can study more regularly than all at once. And yes AAU is harder than other universities because the instructors are stricter. They'll give you work regularly from reading, to group assignments, to regular tests. But the benefit is, an AAU graduate from one of the hardest fields always has an upper hand in the job market