Prolonged development of auditory skills: A role for perceptual anchoring?

Many auditory skills continue to develop beyond infancy and even into adolescence, but the factors underlying this prolonged development remain poorly understood. Of interest here is the contribution of on-line statistical learning of stimulus repetitions (anchoring) to the development of auditory spectral and temporal discrimination, as well as the potential contributions of auditory attention and working memory. Children, aged 6-13 years, as well as adults (age range: 21-33 years) were tested on auditory frequency and duration discrimination. Each type of discrimination was measured in two conditions (XAB and XXXAB) designed to afford different levels of anchoring by varying the number of repetitions of a standard stimulus (X) prior to the presentation of the test tone (A or B) in each trial. Auditory attention and working memory were also assessed. Whereas duration and frequency discrimination in either condition did not reach adult level prior to 11 years of age, the magnitude of the anchoring effect was similar across ages. These data suggest that perceptual anchoring matures prior to the attainment of adult-like discrimination thresholds. Likewise, neither attention nor working memory could account for the observed developmental trajectories. That auditory discrimination and anchoring follow dissociable developmental trajectories suggests that different factors might contribute to the development of each. We therefore conclude that although anchoring might be necessary for attaining good auditory discrimination, it does not account for the prolonged development of auditory frequency and duration discrimination in school-aged children.