Final answer:
This is an example of the Baader-Meinhof phenomenon or frequency illusion, where newly acquired information appears to be encountered more frequently.
Step-by-step explanation:
Marshall's subsequent encounters with the term palindrome after learning about it is most likely the result of the frequency illusion, also known as the Baader-Meinhof phenomenon. This cognitive bias occurs when a word, concept, or thing you just learned about suddenly seems to appear everywhere. It's not that palindromes are being mentioned more frequently; rather, Marshall is now primed to notice them when they appear. Understanding language phenomena like homophones, homonyms, and chiasmus enriches our comprehension and use of language in both written and spoken forms.