According to the APA Dictionary of Psychology to be 'empirical' research is "1. derived from or denoting experimentation or systematic observations as the basis for conclusion or determination, as opposed to speculative, theoretical, or exclusively reason-based approaches. 2. based on experience."
Refers to the process that a scholarly book or journal article goes through when an authors research and writing is evaluated by experts in their discipline or field. In the case of a journal article, peers review articles to determine if they'll be accepted and published in a specific journal. In the case of psychology journals expert peers are evaluating and checking the accuracy and originality of the research being reported on.
When looking at a record in PsycINFO to try to determine if the resource you're looking at is a primary source, it's important to check to see if the article is an empirical study. Look for the "methodology" field of the record.
If there is an indication that the resource you're looking at is an Empirical Study then you know that it's research-based, and is a primary source.
Are original materials based on first-hand accounts of research conducted by the author(s). They are usually written at the time the research is occurring or shortly after the research is complete, and they present new information or discoveries.
Primary sources in psychology: