There is only one exception to the rule about citing all information learned from others, and that is when that information is considered common knowledge.
General common knowledge is information that most people know.
- Examples: capital cities, important historical dates and persons, basic mathematics, common sense observations
This information does not need to be cited. However, it is always best to cite something if you aren’t sure if it is common knowledge or not.
Besides general common knowledge, there is also information that is so well known within a field of study that it is considered common knowledge WITHIN this particular field (discipline-specific common knowledge), though it would not be considered common knowledge outside of this field.
Discipline-specific common knowledge is:
Information that is well known only within a specific field of study
NOT considered common knowledge outside of the specific discipline
Determining discipline-specific common knowledge can sometimes be tricky, so when in doubt, cite!
Citing too much is much less of a concern than not citing enough, because when you over-cite, you have not misrepresented where the material has come from. If you are unsure if something is common knowledge, it is better to cite it than not.