To determine whether acoustically evoked non‐propulsive esophageal contractions form part of an orientation (OR), a defense (DR), or a startle reaction (SR), an experiment employing 16 healthy young subjects was carried out with three levels of intensity, two levels of signal content, and two levels of rise and decay time of stimuli. It was found that: 1) number and amplitude of esophageal contractions to the stimuli increased significantly with increasing stimulus intensity, 2) number and amplitude of contractions to stimuli with sudden and slow rise time did not differ, 3) there was no clear relationship between the occurrence of a contraction and the occurrence of a decelerative or accelerative HR response, 4) there was no difference in number and amplitude of contractions to stimuli with and without signal content. In conclusion, non‐propulsive esophageal contractions are evoked by intense acoustical stimuli regardless of rise time and of signal content of the stimuli. It is suggested that contractile responses of the esophagus to intense exogenous stimuli form part of the DR of the healthy organism.

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