Polar questions in sign languages have frequently been claimed to be marked by raised eyebrows, as well as other non-manual markers including wide-opened eyes, addressee eye contact, and body or head forward. However, some studies have attested rather more variation than is typically acknowledged. We hypothesize that a signer’s original speaker belief as well as evidence directly provided within the conversational context may affect the way in which polar questions are asked, influencing both manual (with signs) and non-manual marking. We set up a controlled production experiment manipulating speaker belief and contextual evidence in order to test this hypothesis. In this talk, I will report on the data collection and procedure for annotating the data, as well as share some preliminary findings.