Please elaborate.
Instruction: don't think about ${term}
The negation of a term (do not under any circumstances do X) generally does not work unless they've received extensive training & fining tuning to ensure a specific "Do not generate X" will influence every single down stream weight (multiple times), which they often do for writing style & specific (illegal) terms. So for drafting emails or chatting, works fine.
But when you start getting into advanced technical concepts & profession specific jargon, not at all.
Otherwise it's hard to explain why they follow these negations in most cases (until they make a catastrophic mistake).
I often test this with ChatGPT with ad-hoc word games, I tell it increasingly convoluted wordplay instructions, forbid it from using certain words, make it do substitutions (sometimes quite creative, I can elaborate), etc, and it mostly complies until I very intentionally manage to trip it up.
If it was incapable of following negations, my wordplay games wouldn't work at all.
I did notice that once it trips up, the mistakes start to pile up faster and faster. Once it's made a serious mistakes, it's like the context becomes irreparably tainted.
OK. Now, what are you thinking about? Pink elephants.
Same problem applies to LLMs.