Human newborns differentiate differing concentrations of sucrose and glucose.

One- to three-day-old infants who sucked to obtain flavored water revealed a precisely graded tongue movement which was sensitive to the gustatory properties of the flavored water. Stronger concentrations of sucrose and glucose elicited movements of greater amplitude than did weaker concentrations; sucrose was effective at lower concentrations than was glucose. These results correspond well with the relative sweetness adults attribute to these solutions in psychophysical studies.