In APA style, when is it acceptable to use all capital letters?

In APA style, the use of all capital letters is acceptable in the running head. The running head is a short version of the title that appears at the top of each page of a manuscript, and it is formatted in all uppercase letters to ensure consistency and visibility, especially in publications. This convention helps distinguish the running head from the rest of the text and follows APA guidelines, which specify that the running head should be succinct and clearly identifiable.

In contrast, the other options are not correct because headings and content in the text are typically formatted using title case rather than all uppercase letters to maintain readability and adhere to standard APA formatting rules. The reference section also does not employ all capital letters, as each entry is formatted with specific capitalization rules appropriate for the type of source cited. Therefore, the correct answer accurately reflects APA style guidelines regarding the use of all capital letters in specific contexts.