The Goldilocks Effect in Infant Auditory Attention

Infants must learn about many cognitive domains (e.g., language, music) from auditory statistics, yet capacity limits on their cognitive resources restrict the quantity that they can encode. Previous research has established that infants can attend to only a subset of available acoustic input. Yet few previous studies have directly examined infant auditory attention, and none have directly tested theorized mechanisms of attentional selection based on stimulus complexity. This work utilizes model‐based behavioral methods that were recently developed to examine visual attention in infants (e.g., Kidd, Piantadosi, & Aslin, 2012). The present results demonstrate that 7‐ to 8‐month‐old infants selectively attend to nonsocial auditory stimuli that are intermediately predictable/complex with respect to their current implicit beliefs and expectations. These findings provide evidence of a broad principle of infant attention across modalities and suggest that sound‐to‐sound transitional statistics heavily influence the allocation of auditory attention in human infants.     

Interference and auditory short-term memory in the bottlenosed dolphin

Interference in auditory short-term memory in the bottlenosed dolphin,Tursiops truncatus (Montagu), was studied using a delayed matching-to-sample task. At each trial, one of two sample sounds, chosen randomly, was projected underwater for 4 sec and then, after a variable delay interval, both sounds were presented. A response to the sound matching the initial sample was reinforced. Correct matching was significantly reduced following short intervals between trials in combination with long delays after the sample (proactive interference), or when a near continuous irrelevant sound was inserted into the delay interval (retroactive interference). There was rapid habituation to interference if the irrelevant sound was short in duration relative to the delay interval. For both proactive and retroactive interference, the errors were predominantly responses to the sample sound appropriate to the prior trial rather than to the current trial, indicating that memory for the relative recency of events (temporal memory) was degraded by interference. When interference was deleted or minimized, temporal memory remained nearly perfect over 30-sec delay intervals, the longest tested. The importance of distinguishing between temporal memory and nontemporal, or event, memory in different forms of the delayed matching task was emphasized.     

Spatial selective attention and asynchrony of cognitive systems in adult dyslexic readers: an ERPs and behavioral study

The aim of this study was to gain additional knowledge about the asynchrony phenomenon in developmental dyslexia, especially when spatial selective attention is manipulated. Adults with developmental dyslexia and non-impaired readers underwent two experimental tasks, one including alphabetic stimuli (pre-lexical consonant–vowel syllables) and the other containing non-alphabetic stimuli (pictures and sounds of animals). Participants were instructed to attend to the right or left hemifields and to respond to all stimuli on that hemifield. Behavioral parameters and event-related potentials were recorded. The main finding was that the dyslexic readers demonstrated asynchrony between the auditory and visual modalities when alphabetic stimuli were presented on the right hemifield. These results suggest that intact reading is linked to a synchronized auditory and visual speed of processing even when spatial selective attention is manipulated. The findings of the current study are discussed in terms of asynchrony between modalities as a neurocognitive marker in developmental dyslexia.     

Newborn infants orient to sounds.

In 2 experiments, the majority of 21 newborn infants who were maintained in an alert state consistently turned their heads toward a continuous sound source presented 90 degrees from midline. For most infants this orientation response was rather slow, taking median latencies of 2.5 sec to begin and 5.5 sec to end. The most important factors in producing this impressive response seem to be the method of holding the infants during testing and the nature of the auditory stimulus.     

Auditory Frequency Resolution in Human Infancy

Frequency resolution is a fundamental capacity of the auditory system that underlies the perception of all complex sounds. The development of this capacity has not been well characterized in humans. This investigation used a nonsimultaneous pulsation threshold technique to examine the development of infant frequency resolution. Psychophysical tuning curves were obtained for 3- and 6-month-olds and for adults at either 500, 1,000, or 4,000 Hz. Both the sensation level and the sound pressure level of the stimulus were varied for adults to determine the contribution of stimulus intensity to age differences in frequency resolution. At 500 and 1,000 Hz, 3- and 6-month-olds' tuning curve widths were equivalent to adults'. At 4,000 Hz, the 3-month-olds' tuning curves were broader than those of 6-month-olds and adults, even when absolute sound pressure level was equivalent. The maturation of psychophysical frequency resolution in infants is discussed in terms of the general development of the auditory system and of nonsensory factors that might contribute to age differences in performance.     

Sound Localization and Sensitivity to Interaural Time Differences in Human Infants

The role of interaural time differences in infants' sound localization was investigated. One experiment on free-field sound localization corroborated previous findings that the minimum audible angle changes substantially toward the end of the first half year after birth, and 3 experiments explored interaural time discrimination in that age range. The first of these 3 experiments used an adaptive psychophysical procedure, showing that infants responded appropriately in a sound lateralization task that provides a direct measure of interaural time discrimination. The other 2 experiments improved on the psychophysical procedure by taking into account the ceiling level on performance in the task. Infants aged 16, 20, and 28 weeks had thresholds in the range of 50 to 75 microsec, with no apparent age difference. These thresholds were much lower than would be predicted from studies of free-field sound localization, indicating that sensitivity to interaural time differences is not a limiting factor for the precision of sound localization in this age range. Instead, age-related changes in free-field sound localization may reflect the need to integrate across different localization cues and to calibrate the changing values of cues due to head growth.     

The relation of unimanual and bimanual reaching to crossing the midline

The present study assessed the development of reaching for objects positioned in front of the contralateral shoulder. In particular, it examined how the development of crossing the midline is related to the development of bimanual reaching. Twenty infants were observed longitudinally at 12, 18, and 26 weeks of age while reaching for two balls (3 cm and 8 cm in diameter) located at three positions (ispsilateral, midline, and contralateral). The reaches were analyzed from video recordings. With age, the infants increasingly adapted the number of hands used to the size of the object. The number of reaches crossing the body midline increased with age. Furthermore, the majority of the midline crossings were part of two-handed reaches for the large ball and occurred at or after onset of bimanual reaching. Together, these findings strongly suggest that the development of crossing the body midline emerges in the context of bimanual reaching. It was concluded that the need to grasp a large ball positioned contralaterally with two hands induces midline crossing. Hence, the development of midline crossings is not exclusively dependent on organismic constraints (e.g., the maturation of hemispheric connections), but rather on their interaction with environmental constraints (e.g., object size).     

Infant visual and vocal responses to television.

To provide a first assessment of television influences on infants in the naturalistic setting of the home, visual and vocal behaviors of 72 infants 6 months of age were recorded during 4 days of exposure to various components of broadcast television programs: sound only, picture only, sound plus picture, or a control stimulus of unpatterned sound plus picture. Infants looked longer at the television set during the sound-plus-picture condition than during the picture-only condition, and they looked longer during both of these patterned picture conditions than during both of the other conditions that lacked a patterned picture. Also, infants vocalized more during the picture-only condition than during the sound-only condition. These findings demonstrate that infants attend to the naturalistic presentation of television stimulation and that they respond differentially to the visual and auditory components of television. The results are discussed in terms of the question of the long-term influence on infants' social responsiveness of substantial levels of exposure to the noncontingent, quasi-social stimulation provided by television.     

Two- to eight-month-old infants' perception of dynamic auditory-visual spatial colocation

From birth, infants detect associations between the locations of static visual objects and sounds they emit, but there is limited evidence regarding their sensitivity to the dynamic equivalent when a sound-emitting object moves. In 4 experiments involving thirty-six 2-month-olds, forty-eight 5-month-olds, and forty-eight 8-month-olds, we investigated infants' ability to process this form of spatial colocation. Whereas there was no evidence of spontaneous sensitivity, all age groups detected a dynamic colocation during habituation and looked longer at test trials in which sound and sight were dislocated. Only 2-month-olds showed clear sensitivity to the dislocation relation, although 8-month-olds did so following additional habituation. These results are discussed relative to the intersensory redundancy hypothesis and work suggesting increasing specificity in processing with age.     

The role of social-referential context in verbal and nonverbal symbol learning

This study examined the role of social-referential context in 13- and 18-month-olds' mapping of verbal and nonverbal symbols to object categories. Infants heard either novel words or novel nonverbal sounds in either a referential or nonreferential context. In all conditions, an experimenter engaged in a social-referential interaction and the label was produced while the infant's attention was directed to the referent. In the referential condition, labels were produced by the experimenter within the context of a familiar naming routine. In the nonreferential condition, labels were emitted from a baby monitor placed near the infant. The study subsequently tested infants' mapping of the symbols to the referent objects using a forced-choice procedure. Although the results for the 18-month-olds were strongest, infants at both ages showed evidence of learning both words and sounds in the referential condition and failed to learn them in the nonreferential condition. Thus, infants successfully learned both words and sounds under the same circumstances at both ages. These findings suggest that the social-referential context, and not the symbolic form per se, determine infants' success at symbol learning.     

It clicks when it is rolled and it squeaks when it is squeezed: what 10-month-old infants learn about object function

Function has been considered important in numerous literatures in the study of cognitive development, yet little is known about what and how infants learn about function. Five experiments examined what 10-month-old infants (N=80) learn about functions that involve a sound produced when an object is acted on. Infants habituated to a single object (Experiment 1) or multiple objects that performed the same function (Experiment 2) learned both the actions and the sounds. Infants did not appear to learn relations between actions and sounds (Experiment 3) or appearances and sounds (Experiment 4), although they did learn the relations between appearances and actions (Experiment 5). These results are discussed in terms of how infants learn about object function.     

The A-Not-B Error: Results from a Logistic Meta-Analysis

A meta-analysis of the A-not-B error was conducted using logistic regression on studies conducted before September 1997 (107 data points). An earlier meta-analysis by Wellman, Cross, and Bartsch revealed that age, delay between hiding and retrieval, and number of hiding locations were significant predictors of both the proportion of infants who searched correctly on B trials and the proportion of infants who searched perseveratively. The current analysis replicated these findings with two exceptions: (1) The number of trials at the A location was a significant predictor, and (2) the number of locations was a significant predictor of the proportion of infants who searched perseveratively, but not the proportion of infants who searched correctly. Implications of these findings are discussed and a quantitative version of a hierarchical competing-systems model of infant search is proposed.     

Effective Action by Infants to Contact Objects by Reaching and Leaning

The ability of infants aged 8–12 months to coordinate their arm and trunk movements to contact an object located in different positions was investigated in 2 experiments. In the first, 8- and 10-month-old infants reached for near objects but both reached and leaned for more distant ones indicating that they perceived that forward leaning extends the range of contact beyond that of reaching alone. In addition, arm and trunk movements were initiated simultaneously; visual information concerning object distance was sufficient to activate an integrated reaching-and-leaning response. Object distances were increased and a mechanical aid was provided on half the trials in the second experiment with 10- and 12-month-old infants. For both age groups the degree of leaning was reduced for objects that were out of reach without the aid. Only older infants were able to use the aid to extend partially their range of contact. Overall the results support the conclusions that, by at least 8 months, infants perceive that leaning extends their effective reaching space; by 10 months they perceive the limits within which reaching together with leaning is likely to be effective; and by 12 months they begin to perceive how this space may be extended by a mechanical aid.     

HEARING AND AGING

Although changes in hearing acuity are expected to occur with aging, the impact of that sensory loss is frequently obscure, often discounted, and not appreciated. However, significant elements of communication comprising a complex matrix of sounds often are lost or distorted as individuals age. The invisible handicap of hearing loss must not be ignored. Across the many types of auditory differences among the aging, an appreciation of the effect of reduced access to meaningful sounds can help both the student and practitioner of gerontology gain insight into clients response behaviors that are socially adequate but insufficient or those that seem off target, out of place, or even unacceptable. Such knowledge can give gerontologists an advantage in handling otherwise stressful situations. Additionally, they can gain the ability to assess the need for changes in communication patterns or for professional consultation to ensure the quality of life of those aging individuals in their care.     

Similar Sound Separation and Cumulative Introduction in Learning Letter-Sound Correspondences

Abstract

The instructional procedure of separating the similar sounds e and i from each other during instruction was evaluated in two experiments. In Experiment 1,42 first graders were assigned to a group in which e and i were introduced together or were separated by four other letters. Children in the similar-separated group made more correct responses to the two target letters during training, but the posttest scores were low and did not differ for the two groups. By measuring trials to criterion, Experiment II investigated the efficiency of separating similar sounds and of cumulatively introducing each sound. In the cumulative introduction procedure, children were brought to criterion on each group of sounds before a new sound was introduced. Thirty-five pre-schoolers completed training in one of three groups: similar-separated with cumulative introduction, similar-together with cumulative introduction, and similar-separated with simultaneous introduction. Children from the similar-separated group with cumulatively introduced sounds reached criterion significantly more quickly than the similar-together group and the simultaneous group. Posttest scores for all the children were substantially higher than in Experiment I and were significantly higher for the two cumulative introduction groups than for the simultaneous group.     

Auditorysame/different concept learning by monkeys

Two rhesus monkeys learned the auditory abstract concept ofsame/different. They were trained with 38 different environmental and natural sounds, which were arranged in different combinations as training progressed. Upon transfer to 138 different novel stimuli, they performed as well (78.8% correct) on the first exposure to the novel stimuli as they did (77.3%) with their training stimuli. The comparatively large set of training sounds, contact with the sound source, and a special fading procedure are thought to have contributed to the monkeys’ being able to learn this concept. Implications for species’ similarities/differences in cognitive processing are discussed.     

Intermodal Perception of Adult and Child Faces and Voices by Infants

This research investigated the ability of 4- and 7-month-old infants to match unfamiliar, dynamic faces and voices on the basis of age or maturity. In Experiment 1, infants received videotaped trials of an adult and a child of the same gender, side by side, speaking a nursery rhyme in synchrony with one another. The voice to one and then the other face was played in synchrony with the movements of both faces in a random order across 12 trials. On one block of 6 trials a man and a boy were presented, and on the other block a woman and a girl. Results indicated significant matching of the faces and voices at both ages, and the infant's prior experience with children appeared to facilitate matching at 7 months. Further, a visual preference for the children's faces was found. Experiment 2 assessed matching to the same events by 7-month-olds, only with the faces inverted. Results indicated no evidence of matching; however, the visual preference for the children's faces was replicated. Together, the findings suggest that infants are able to detect invariant intermodal relations specifying the age or maturity of a person's face and voice. This matching was most likely based on information that was degraded by inverting the faces, including invariant relations between the sound of the voice and configurational aspects of the face, or between temporal aspects of the voice and the relative motion of facial features.     

Learning for Everyday Life: Students’ standpoints on loud sounds and use of hearing protectors before and after a teaching–learning intervention

Researchers have highlighted the increasing problem of loud sounds among young people in leisure-time environments, recently even emphasizing portable music players, because of the risk of suffering from hearing impairments such as tinnitus. However, there is a lack of studies investigating compulsory-school students’ standpoints and explanations in connection with teaching interventions integrating school subject content with auditory health. In addition, there are few health-related studies in the international science education literature. This paper explores students’ standpoints on loud sounds including the use of hearing-protection devices in connection with a teaching intervention based on a teaching–learning sequence about sound, hearing and auditory health. Questionnaire data from 199 students, in grades 4, 7 and 8 (aged 10–14), from pre-, post- and delayed post-tests were analysed. Additionally, information on their experiences of tinnitus as well as their listening habits regarding portable music players was collected. The results show that more students make healthier choices in questions of loud sounds after the intervention, and especially among the older ones this result remains or is further improved one year later. There are also signs of positive behavioural change in relation to loud sounds. Significant gender differences are found; generally, the girls show more healthy standpoints and expressions than boys do. If this can be considered to be an outcome of students’ improved and integrated knowledge about sound, hearing and health, then this emphasizes the importance of integrating health issues into regular school science.     

Infants' attentional responses to frequency modulated sweeps

In 3 experiments, the attentional responses of 4-month-old infants to frequency-modulated (FM) sweeps corresponding to the frequency range of adult-to-infant and adult-to-adult intonation patterns were assessed. In Experiment 1, infants were observed to discriminate "exaggerated" (i.e., adult-to-infant) FM sweeps from "normal" (i.e., adult-to-adult) FM sweeps in a habituation-dishabituation paradigm but did not selectively attend to one over the other. In Experiment 2, where the same stimuli were used in a paired-comparison paradigm, again no differential attention was observed. In Experiment 3, the most exaggerated sweep was paired against a continuous, monotonic pure tone, but again no difference in salience was observed. These data suggest that the extent of modulation or intonation of an auditory stimulus per se does not constitute a salient cue for infants' attention to sound.     

Auditory delayed discriminations by the dolphin: Nonequivalence with delayed-matching performance

Working memory in a bottlenosed dolphin was tested in both indirect and direct auditory delayed-discrimination tasks in which a correct spatial response was conditional upon the nature of a preceding sound. In the indirect task, either one of two possible sounds was briefly presented. After a prescribed delay, the dolphin was cued to go either to a left-hand or right-hand paddle pair. Responses to the outer paddle of a pair were rewarded following sound A, and responses to the inner paddle of a pair were rewarded after sound B. In the direct delayed-discrimination task, only one paddle pair was used in each session. In both tasks, the delay interval between the discriminative sound stimulus and the opportunity for a spatial response was progressively increased over sessions until the animal failed to meet a specified performance criterion or self-terminated a session. Delay limits of about 30 and 60 sec were obtained in the indirect and direct tasks, respectively. The increase in delay limit in the latter task was attributable to the use of an overt mediational response during the longer delays. In both cases, however, the obtained delay limits fell considerably short of the 2- to 3-min limits obtained in auditory delayed-matching studies using the same test sounds and the same subject. The task differences indicate that working memory functions cannot depend upon memory of the predelay stimulus alone, but must be determined in part by additional processes.