Magnitude estimates of amino acids for young and elderly subjects

Serial dilutions of twenty-three amino acids were presented to young and elderly subjects who rated the relative intensities of the dilutions using the magnitude estimation procedure. In each case the slope of the psychophysical function relating concentration and perceived intensity was flatter for the elderly subjects: the mean ratio (slope (young)/slope (elderly)) was 2.55. This result could be due to an age-related decline in gustatory apparatus or associated central areas as well as memory loss and decline in performance often found in the elderly. No conclusive relationships between the slopes of the psychophysical functions were found with chemical structure, taste quality, or solubility.