It should be obvious to the reader why you’re including a reference without your explicitly saying so.
DO NOT quote from the articles, instead paraphrase by putting the information in your own words.
When an idea is complex, don’t be afraid to use a real-life example to clarify it for your reader.
The introduction will end with a brief overview of your study and, finally, your specific hypotheses.
Be careful about citing your sources (see APA manual).
Make sure there is a one-to-one correspondence between the articles you’ve cited in your intro and the articles listed in your reference section.
Note that in some studies (e.g., questionnaire studies in which there are many measures to describe but the procedure is brief), it may be more useful to present the Procedure section prior to the Materials section rather than after it. (e.g., money, extra credit points) Write for a broad audience. 280...” Rather, write (for instance), “Students in a psychological statistics and research methods course at a small liberal arts college….” Try to avoid short, choppy sentences.
Total number of participants (# women, # men), age range, mean and SD for age, racial/ethnic composition (if applicable), population type (e.g., college students). Combine information into a longer sentence when possible.
Remember that your audience is the broader scientific community, not the other students in your class or your professor.
Therefore, you should assume they have a basic understanding of psychology, but you need to provide them with the complete information necessary for them to understand the research you are presenting.