I'm a transfer student, and I have worked in 4 labs, and two of them for 1 year and currently still in them. I am almost done with my senior thesis, and I also have a ton of extra curricular (started a club, volunteered with various programs). Not sure how much the extracurricular counts? I don't know how much more research experience I could have had straight out of undergraduate, but I'm assuming they want you to work a couple years in a lab, and get published or have your name mentioned, is that the idea? I don't know what my application is lacking otherwise. Higher GPA, higher GRE scores? (Thank you by the way)