In the context of the article "What is déjà vu?" by Anne Cleary, the term "garner" generally means to gather or collect. Depending on the context in which it is used in the article, it could refer to accumulating knowledge, insights, or data related to déjà vu experiences.
Among the options you provided, "amass" is the closest synonym to "garner," as both words imply collecting or gathering a substantial amount of something.
If you need a more specific interpretation of "garner" or further context from the article, feel free to provide additional details!