Answered by Merron, Hiring Expert at DuPont, on Wednesday, June 6, 2018
Hello and great question! What I typically suggest in this case is to list that time on your resume as "Volunteer." It does help to have formal internship experience but as long as you list your field research experience on your resume as "Volunteer" time, I think that will serve you well. It will show that you're giving (volunteering your time to work with your professors, at no cost to them!), and self-motivated.