Gap detection in infants, children, and adults

Listeners who were 6.5 months, 12 months, 5 years, and 21 years of age were required to discriminate a pair of 500‐Hz, Gaussian‐enveloped tone pips from a short 500‐Hz tone of the same duration and total energy. Groups of 6.5‐month‐old infants were tested on a single gap duration: 8, 12, 16, 20, 28, or 40 ms. Groups of 12‐month‐olds were also tested on a single gap duration: 8, 12, 16, or 20 ms. The 5‐year‐old children and adults were tested on gap durations of 8, 12, and 16 ms. The mean performance of 6.5‐month‐olds significantly exceeded chance levels on all gap durations except 8 ms, and that of 12‐month‐olds was above chance levels on all gap durations. For 5‐year‐old children and adults, mean performance also exceeded chance levels for all gap durations tested. Adults performed significantly better than 5‐year‐old children on gap durations of 12 and 16 ms. Gap‐detection thresholds, defined by a performance criterion of d′=0.5, were estimated at 11, 5.6, and 5.2 ms for infants, children, and adults, respectively. It is likely that smaller adult–infant differences in the present study compared to those reported in previous research stem from our use of Gaussian‐enveloped tone pips and the consequent minimization of adaptation effects.