Relationships Among Responses in the Human Newborn: The Non‐association and Non‐equivalence Among Different Indicators of Responsiveness

To determine whether different responses are equivalent indicators of stimulus effectiveness and whether a single mechanism can account for responsiveness in different systems, cardiac accelerations, ipsilateral eye movements, and finger movements were simultaneously recorded when lateralized auditory stimuli of graded intensity were presented to 2‐day old infants (N = 21). The responses were not equivalent indicators of stimulus effectiveness as evidenced by the finding of different thresholds for different responses. Furthermore, it was found that an infant's relative responsiveness as defined by one response does not predict his relative responsiveness on other responses. Finally the simultaneously measured responses to a stimulus did not co‐occur more frequently than would be expected if the responses were independently determined. The results raise serious questions as to the adequacy of concepts of generalized arousal and a unitary orienting response in accounting for behavioral organization in the human newborn.