When should parentheses be used in writing?

Using parentheses in writing is typically reserved for providing additional information that is supplementary or clarifying without interrupting the flow of the main text. This means that the information contained in parentheses is not essential to the main thought but enhances the reader's understanding. By placing this kind of ancillary information in parentheses, writers can keep the primary message clear while still offering useful context or details.

For example, one might say, "The committee will meet on Tuesday (March 15, 2023) to discuss the project." The date provides useful context but isn't critical to the main point, making parentheses the appropriate choice.

The other options do not accurately represent the typical use of parentheses: separating titles from authors usually relies on commas or a different punctuation style, indicating that a list will follow typically means using colons or other means, and joining two ideas generally involves conjunctions or other grammatical structures rather than parentheses. Thus, supplementary information is the primary function of parentheses.