I did a mock interview and they asked really random things. They also asked : tell me about a weakness you have, why are you different from other applicants, why are you interested in this specifically, why this program / POI, what are your strengths, where are you / social psych in 10 years,
I am not sure if these are accurate as I had to go to career services, which at my uni is mostly focused on job placement but it was still a good experience. Plus, she is setting up a panel for me with Psych PhD grads next time... that is in 2 weeks.