I meant to be less specific than "hire someone", but I'd wager that once a subconscious impression is formed, you'd be more likely to bias your interpretation of whatever else they say.
Right, I am sure I have a first impression, which could be good or bad, and that impression does inform my later views. However, just objectively I know for a fact that I declined some candidates I initially liked and I hired a few people who initially was super shy/not communicative.