Julia Jones Huyck

Late maturation of auditory perceptual learning.

Adults can improve their performance on many perceptual tasks with training, but when does the response to training become mature? To investigate this question, we trained 11-year-olds, 14-year-olds and adults on a basic auditory task (temporal-interval discrimination) using a multiple-session training regimen known to be effective for adults. The adolescents all began with performance in the adult range. However, while all of the adults improved across sessions, none of the 11-year-olds and only half of the 14-year-olds did. The adolescents who failed to learn did so even though the 10-session training regimen provided twice the number of sessions required by adults to reach asymptotic performance. Further, over the course of each session, the performance of the adults was stable but that of the adolescents, including those who learned, deteriorated. These results demonstrate that the processes that underlie perceptual learning can continue to develop well into adolescence.

Learning, worsening, and generalization in response to auditory perceptual training during adolescence

While it is commonly held that the capacity to learn is greatest in the young, there have been few direct comparisons of the response to training across age groups. Here, adolescents (11-17 years, n = 20) and adults (≥18 years, n = 11) practiced detecting a backward-masked tone for ∼1 h/day for 10 days. Nearly every adult, but only half of the adolescents improved across sessions, and the adolescents who learned did so more slowly than adults. Nevertheless, the adolescent and adult learners showed the same generalization pattern, improving on untrained backward- but not forward- or simultaneous-masking conditions. Another subset of adolescents (n = 6) actually got worse on the trained condition. This worsening, unlike learning, generalized to an untrained forward-masking, but not backward-masking condition. Within sessions, both age groups got worse, but the worsening was greater for adolescents. These maturational changes in the response to training largely followed those previously reported for temporal-interval discrimination. Overall, the results suggest that late-maturing processes affect the response to perceptual training and that some of these processes may be shared between tasks. Further, the different developmental rates for learning and generalization, and different generalization patterns for learning and worsening imply that learning, generalization, and worsening may have different origins.

Rapid perceptual learning of noise-vocoded speech requires attention

Humans are able to adapt to unfamiliar forms of speech (such as accented, time-compressed, or noise-vocoded speech) quite rapidly. Can such perceptual learning occur when attention is directed away from the speech signal? Here, participants were simultaneously exposed to noise-vocoded sentences, auditory distractors, and visual distractors. One group attended to the speech, listening to each sentence and reporting what they heard. Two other groups attended to either the auditory or visual distractors, performing a target-detection task. Only the attend-speech group benefited from the exposure when subsequently reporting noise-vocoded sentences. Thus, attention to noise-vocoded speech appears necessary for learning.

Transient sex differences during adolescence on auditory perceptual tasks

Many perceptual abilities differ between the sexes. Because these sex differences have been documented almost exclusively in adults, they have been attributed to sex-specific neural circuitry that emerges during development and is maintained in the mature perceptual system. To investigate whether behavioral sex differences in perception can also have other origins, we compared performance between males and females ranging in age from 8 to 30 years on auditory temporal-interval discrimination and tone-in-noise detection tasks on which there are no sex differences in adults. If sex differences in perception arise only from the establishment and subsequent maintenance of sex-specific neural circuitry, there should be no sex differences during development on these tasks. In contrast, sex differences emerged in adolescence but resolved by adulthood on two of the six conditions, with signs of a similar pattern on a third condition. In each case, males reached mature performance earlier than females, resulting in a sex difference in the interim. These results suggest that sex differences in perception may arise from differences in the maturational timing of common circuitry used by both sexes. They also imply that sex differences in perceptual abilities may be more prevalent than previously thought based on adult data alone.

Development of temporal‐interval discrimination during adolescence

The accurate perception of time intervals in the 10–100‐ms range plays an important role in sensory encoding, including the processing of speech, yet little is known about the development of this ability, particularly during adolescence. Here, auditory temporal‐interval discrimination thresholds were measured in normally developing individuals aged 11 (n=14), 14 (n=8), and 18–26 (n=17) years. Both average performance (mean within‐listener threshold) and performance consistency (within‐listener standard deviation) were evaluated for each listener with a 100‐ms standard at each of two frequencies, 1 and 4 kHz. At the group level, for both frequencies, average performance improved significantly, from ∼48 to ∼22 ms, between 11 and 14 years of age (both p≤0.02), but did not improve further between 14 years and adulthood (both p≥0.92). There were parallel improvements in performance consistency. At the individual level, while the majority of 11‐year‐olds showed poorer performance than 14‐year‐olds and adults on...

Development of perception and perceptual learning for multi-timescale filtered speech

The perception of temporally changing auditory signals has a gradual developmental trajectory. Speech is a time-varying signal, and slow changes in speech (filtered at 0-4 Hz) are preferentially processed by the right hemisphere, while the left extracts faster changes (filtered at 22-40 Hz). This work examined the ability of 8- to 19-year-olds to both perceive and learn to perceive filtered speech presented diotically for each filter type (low vs high) and dichotically for preferred or non-preferred laterality. Across conditions, performance improved with increasing age, indicating that the ability to perceive filtered speech continues to develop into adolescence. Across age, performance was best when both bands were presented dichotically, but with no benefit for presentation to the preferred hemisphere. Listeners thus integrated slow and fast transitions between the two ears, benefitting from more signal information, but not in a hemisphere-specific manner. After accounting for potential ceiling effects, learning was greatest when both bands were presented dichotically. These results do not support the idea that cochlear implants could be improved by providing differentially filtered information to each ear. Listeners who started with poorer performance learned more, a factor which could contribute to the positive cochlear implant outcomes typically seen in younger children.

Comprehension of Degraded Speech Matures During Adolescence

Purpose The aim of the study was to compare comprehension of spectrally degraded (noise-vocoded [NV]) speech and perceptual learning of NV speech between adolescents and young adults and examine the role of phonological processing and executive functions in this perception. Method Sixteen younger adolescents (11-13 years), 16 older adolescents (14-16 years), and 16 young adults (18-22 years) listened to 40 NV sentences and repeated back what they heard. They also completed tests assessing phonological processing and a variety of executive functions. Results Word-report scores were generally poorer for younger adolescents than for the older age groups. Phonological processing also predicted initial word-report scores. Learning (i.e., improvement across training times) did not differ with age. Starting performance and processing speed predicted learning, with greater learning for those who started with the lowest scores and those with faster processing speed. Conclusions Degraded (NV) speech comprehension is not mature even by early adolescence; however, like adults, adolescents are able to improve their comprehension of degraded speech with training. Thus, although adolescents may have initial difficulty in understanding degraded speech or speech as presented through hearing aids or cochlear implants, they are able to improve their perception with experience. Processing speed and phonological processing may play a role in degraded speech comprehension in these age groups.

Community network for deaf scientists

We are a community of scientists who have personally experienced the barriers imposed by hearing loss described by G. Buckley et al. in their Letter “Building community for deaf scientists” (20 January, p. [255][1]). They propose an institutional hub for deaf and hard-of-hearing (D/HH) trainees

A perceptual‐learning deficit in adults with reading disorders interpreted as evidence of a developmental delay.

Individuals with reading disorders have difficulty reading despite having normal intelligence. Many also exhibit a number of auditory perceptual deficits. According to one proposal, these deficits arise because perceptual development in these individuals is delayed in childhood and then halted, for skills on which improvements would normally continue into adolescence, around age 10 (presumably due to brain changes associated with puberty). If so, perceptual skills with long developmental courses should be impaired in adults with reading disorders. While perceptual development is typically examined through naive performance, this prediction was tested here using a perceptual‐learning paradigm. Ten adults with reading disorders were trained on a temporal‐interval discrimination task using a multiple‐session training regimen known to yield learning reliably in adults, but rarely in adolescents [Huyck and Wright, Developmental Science (in press). Seven of the ten did not improve with training. Thus, the response to training in the adults with reading disorders more closely resembled that of adolescent than of adult controls. This result is consistent with the idea that perceptual development may be delayed and then halted in individuals with reading disorders and highlights prolonged maturational changes in a perceptual skill other than naive performance.

The time course of maturation on auditory tasks can differ between the average and consistency of performance and also between the sexes.

Between infancy and adulthood, performance on auditory perceptual tasks becomes both better on average and more consistent. However, little is known about the relationship between these two aspects of performance during development. This issue was investigated by using a cross‐sectional design to estimate the ages at which measures of average performance (the mean of multiple threshold estimates for each listener) and performance consistency (the within‐listener standard deviation of those estimates) became adultlike on two temporal‐interval discrimination and four masking conditions (ages: 8–30 years, n=50–142 per condition). Average performance became mature before consistency on two simultaneous‐masking conditions, after consistency on two nonsimultaneous masking conditions (backward and forward), and at the same time as consistency on the two temporal‐interval discrimination conditions. In addition, on five of the six conditions, males matured more quickly than females on both measures or on consisten...