Is undergrad research experience related to the undergrad field preferred, or can I do research on the area I plan to study in grad school instead?
Is undergrad research experience related to the undergrad field preferred, or can I do research on the area I plan to study in grad school instead?


It's actually just the opposite: research in the area you plan to study in grad school is preferred, because it sheds more light on your talent and preparation in this field and it demonstrates that you understand what's involved in this work.  If your undergraduate research is not in the field you plan to study, then there's a risk that you won't do as well in that field or won't enjoy it.