On meaningful/non meaningful memory: some individuals have much better access, or retrieval efficiency, when meaning is involved, or skills are contextualized. The performance difference you report in the context of high/low interest is essentially the same thing. This is not, by the way, necessarily correlated with working memory per se; someone with exceptionally high working memory could still have a differential between contextualized and decontextualized retrieval.

...pronounced like the long vowel and first letter of the alphabet...