a 0.001 second delay. In delayed auditory feedback, the delay is artificially disrupted. Studies have found that in children ages 4–6 there is less disturbance of speech than in children ages 7–9 under a delay of 200 ms. Younger children are maximally disrupted around 500 ms while older children around 400 ms. A 200 ms delay produces maximum disruption for adults. As the data collected from these studies indicate, the delay required for maximum disruption decreases with age. However, it increases again for older adults, to 400 ms. Sex differences in DAF show no difference or indicate that men are generally more affected than women, indicating that the feedback subsystems in the vocal monitor process could be different between the sexes. In general, more rapid, fluent speakers are less affected by DAF than slower, less fluent speakers. Also, more rapid fluent speakers are maximally disrupted by a shorter delay time, while slower speakers are maximally disrupted under longer delay times. Studies using computational modeling and functional magnetic resonance imaging (fMRI) have shown that the temporo-parietal regions function as a conscious self-monitoring system to support an automatic speech production system and that projections from auditory error cells in the posterior superior temporal cortex that go to motor correction cells in right frontal cortex mediate auditory feedback control of speech. Effects in non-humans Continuous delayed auditory feedback in Zebra finch songbirds caused them to change their song syllable timing, indicating that DAF can change the motor program of syllable timing generation during short periods of time in zebra finches, similar to the effects observed in humans. References Sound Anti-stuttering devices