No, I really don't have verbal reflexes. Even in extreme pain I tend to be close to silent. However, I am prone to having quiet panic attacks in very loud situations. In extreme cases I'll shut down, move slowly, breathe slowly, tense up, feel my heart go into arrhythmia, feel my limbs go numb, then black out.
Needless to say, volume stresses me out, and my response to stress is very... restrained. One of several reasons I value physical isolation.
My girlfriend makes all kinds of odd noises when she's startled, and it drives me crazy. I can't imagine having so little restraint.
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'I don't know if that's an Asperger's thing or not, I think it's just being reasonable.' - Bram Cohen