It's pretty common among SIAI-ish people to make super-exaggerated expressions/postures when thinking, which is a pretty good excuse to break eye contact for a bit. I'm not sure if the exaggeratedness is just another meme (like how people tend to answer questions with "So...... (insert exposition and then answer)" ever since Steve and Mike Blume did it a lot) or if it somehow helps people think. Steve used to do some mudra-like thing and looked like he was charging up to fire a telekinetic energy projectile but sadly he hasn't done it in ages (these days he furrows his brow and sometimes puts his head in his hands, I think). Justin would say "checking, checking..." when evaluating a claim, which made me happy since often it'd be followed with a "huh" of insight/updating. I normally bury my head in my hands or rest my chin on my hand/thumb and my pointer finger on my lips. Jasen's thinking movements are more traditional and less exaggerated but still moreso than non-SIAI folk I think.