Auditory stream segregation improves infants' selective attention to target tones amid distracters

This study examined the role of auditory stream segregation in the selective attention to target tones in infancy. Using a task adapted from Bregman and Rudnicky's 1975 study and implemented in a conditioned head-turn procedure, infant and adult listeners had to discriminate the temporal order of 2,200 and 2,400Hz target tones presented alone, preceded and followed by 1,460Hz flanker tones, and presented within a series of 1,460Hz captor tones meant to release the target tones from the effects of the flankers by capturing the flankers into a separate stream. Infants showed the same pattern of discrimination across conditions as adults: discrimination of target tones in the target-alone condition, a decrease in performance when flanker tones were introduced, and a return to target-alone level in the captor condition. These results suggest that infants' perceptual organization of tones is similar to that of adults, and that their ability to selectively attend to target sounds and ignore distracters depends on the structural properties and perceptual organization of the nontarget sounds.