1) As a reflex action 2) By a mechanism 3) In a mechanical manner 4) In a reflex manner 5) Insentience 6) Instinctively 7) Involuntarily 8) Mechanically 9) Perfunctorily 10) Reflexively 11) Unconsciously 12) Unthinkingly 13) Without thinking 14) Without thought 1) Impulsively 2) Ipso facto 3) Mechanically 
• (adv.) In an automatic manner.
[Adverb] When something happens as a result of another action.
Au`to·mat'ic·al·ly adverb In an automatic manner. 
[adv] - in a reflex manner
automatically 1. In a reflex manner; as, 'He answered automatically.' 2. In a mechanical manner; by a mechanism operating with minimal human intervention; independent of external control.
to function independently
adverb in a reflex manner; `he answered automatically`