Behavioral thresholds for tones during infancy.
An adaptive up-down tracking procedure was used in combination with a visually reinforced head turn response to examine auditory sensitivity for 500, 2000, and 8000-Hz tone bursts in infants 6 to 18 months of age. Six- and 10-month-old infants were tested with headphone presentation of stimuli, while 10-, 14-, and 18-month-olds were tested in sound field. Infant threshold estimates for both headphone and sound field were within 15 dB of adult comparisons for all frequencies and age groups. Six-month-olds were significantly less sensitive to the 8000-Hz tone than to either of the lower frequency stimuli, but older infants demonstrated approximately equal sensitivity for all three frequencies tested.
D000367:Age Factors; D001309:Auditory Threshold / Q000502:physiology; D001933:Brain Stem / Q000254:growth & development; D003216:Conditioning, Operant; D004432:Ear, Middle / Q000254:growth & development; D006257:Head / Q000502:physiology; D006320:Hearing Tests / Q000379:methods; D006801:Humans; D007223:Infant; D011571:Psychoacoustics; D002666:Psychology, Child; D011594:Psychometrics; D012016:Reference Values; D012054:Reinforcement, Psychology