Review articles are secondary sources of information.
To find topics...
If you are not provided with a topic, one strategy to find topics is to browse recent issues of journals such as Psychological Bulletin for review articles. Review articles are an excellent source of information for someone starting research on a topic. They deliver a historical overview of past research on a topic and provide a way to identify leading researchers -- and literature -- in the particular area.
Start broad, then narrow or focus your topic as you become more informed.