Sometimes, your instructor will ask you to find "empirical" studies. What is an empirical study?
empirical 1a. Relying on or derived from, observation or experiment: empirical results supported the hypothesis. b. Verifiable or provable by means of observation or experiment. 2. Guided by practical experience and not theory. From: The American Heritage Dictionary, 2000.
What does this mean for you? Well, you are going to need to find articles that present the research done by the authors, rather than news articles or literature reviews in which the authors describe research done by someone else. You need to examine each article to make sure it is an empirical study. Remember, however, that although you may be required to find a certain number of empirical studies, other types of information, including literature reviews, may still be valuable in addition to the empirical studies.
Here is an abstract of an article from a journal called Media Psychology. Note some of the clues that tell us that the article is an empirical study. The authors describe how they "investigate", "assess" and interpret "results" using a "sample population".
The present study used autobiographical memory to investigate the social experience and short- and long-term effects of seeing frightening movies on a date, using a sample population of 125 males and 108 females (mean age of both 19.2 yrs), and extending D. Zillmann and J. B. Weaver's (1996) model of differential gender-role behaviors to persons' own real-life dating experiences. Young adult participants (1) recalled the experience of watching a scary movie on a date, and (2) were assessed for levels of gender-role traditionality, sensation seeking, and dispositional empathy. Results showed that almost all individuals could recall such a date. Although men reported more positive reactions to the film and women more negative reactions, the experience appeared to have some social utility for both. Sex was a better predictor than the gender-role measures for Negative Reactions, Sleep Disturbances, and the likelihood of being Scared Today by the movie. Sensation-Seeking and Empathy were modest predictors of the same variables. In sum, the dating context seemed to encourage both men and women to behave and react in highly gender-stereotypical ways. (PsycINFO Database Record (c) 2002 APA, all rights reserved).
How do you find the empirical studies you need?
Generally the best place to start is PsycINFO. PsycINFO is a large database of articles in psychology and related fields. One of its nice features is that it allows you to limit to empirical studies. Be warned! Using the empirical study limit does not guarantee that you will get only empirical studies. Occasionally items are entered as empirical studies, yet are not. You will need to look at each item to make sure it fits the criteria for an empirical study.