reflex
reflex response
reflex action
instinctive reflex
innate reflex
inborn reflex
unconditioned reflex
physiological reaction

The child may not be regulating feeding with physiological reactions of hunger.

It is also used in behavior therapy to measure physiological reactions such as fear.

Steve believes that a physiological reaction would be more likely.

"Amazes me how the memory of something like that can cause a physiological reaction after all these months."

To smile when you are angry can be a normal physiological reaction.

This normal physiological reaction to invasion by foreign organisms is called inflammation.

The subject upon which all the workers were concentrating their attention was temperature coefficients of physiological reactions.

Does everyone have the same physiological reaction when telling a lie?

Shivering is a physiological reaction designed to warm a cold body fast.

What worries me is the fact that you are prone to physiological reaction.