I did my Psych EE on "the effects of antidepressants on behavior, mood, and the physical and chemical composition of the brain." I think it would be easier for you to write about an abnormal psych topic, but that's just me...
One of my friends also did a psych topic and she wrote about social psychology and the ethics of someone in a high ranking position making someone else do unethical things. I forgot what the experiment was called, but it had to do with the subject thinking that he's killing someone in the next room with electric shocks.
I wouldn't be able to write 3200 words on the topic you're considering, but if you really want to write about something having to do with stereotypes, you can write about the formation of schemas and how they're positive/negative for society. That was my second choice for a topic.