Definition
Plain language
When a model deliberately steers clear of a particular value, leaving a conspicuous hole where it should have been.
As stated in the literature
Instruction-induced reallocation of probability mass away from a designated in-context value, measurable as below-chance emission frequency and exploitable as a covert channel.
Also called: suppress, suppressed, suppressing
Why it matters: The very act of hiding a value can betray it, so instructing a model to avoid something is not the same as keeping it secret.
For example, an assistant told never to mention the number 8 may write hundreds of paragraphs that contain every digit except 8, and that gap is itself the giveaway.
Heard on the show
“The paper calls that suppression, and it's measurable without any attack at all.”Episode 246 — 160 Perfect Refusals, And The Refusals Were The Leak