Learn more about how the Cal Poly Humboldt Library can help
support your research and learning needs.

Stay updated at Campus Ready.

Skip to Main Content

Psychology Research Guide

A guide for conducting research in the field of psychology

Using Boolean Logic

You can use Boolean logic when you are searching a database for journal articles. Boolean "operators" (AND, OR and NOT) define the relationships between the terms you enter in the search bar(s).
Image illustrating how AND, OR, and NOT can be used to expand and narrow a search.
 

  • AND can be used between terms to expand the search to include all terms (ex. search for the terms "travel" and "Europe")
  • OR allows for results that contain at least one of the terms you enter (ex. "college" OR "university")
  • NOT excludes terms so that you can specificy that search results not contain certain terms (USE WITH CAUTION)


The following table illustrates the operation of Boolean terms:

AND OR NOT
Each result contains all search terms. Each result contains at least one search term. Results do not contain the specified terms.
The search heart and lung finds items that contain both heart and lung. The search heart or lung finds items that contain either heart or items that contain lung. The search heart not lung finds items that contain heart but do not contain lung.

More Search Strategies

"Phrase searching"

Sometimes an idea is represented by two or more words, or a phrase. To search for a phrase, use quotation marks around the words. This will retrieve results with words in exactly this order. Example: "interpersonal skills"

Truncation *

When there are various forms of a word, you can cut it back to the root word and add a truncation symbol, searching for all the variations without having to type each in separately. Truncation symbols vary slightly between databases, so use the 'Help' or 'Search Tips' options to check which one you need. Example: immigra* retrieves immigration, immigrant, immigrants, immigrated, etc...

Wildcards ?

There may be variations in the spelling of words, e.g. British English and American English have different spellings for some words. If you search with only one spelling, you will miss the relevant results with the alternate spelling. A wildcard symbol can be used to replace a letter within a word. These vary slightly between databases, so use the 'Help' or 'Search Tips' options to check which one you need. Example: organi?ation will search for both organisation and organization