Staring != sustained, although defining that is hard. What you're trying to do is establish that the eye contact is not incidental; "solid" may be a better wor

Staring != sustained, although defining that is hard. What you're trying to do is establish that the eye contact is not incidental; "solid" may be a better word that "sustained". If someone is unwilling to hold eye contact with you, they are unwilling to talk. That's the test you're trying to run.