The effects of sound duration on newborns' head orientation

Two experiments assessed the importance of sound duration for eliciting head orientation responses from newborn infants. In Experiment 1, thirty infants turned with equal frequency toward 20-s continuous rattle sounds and 20-s trains of rattle segments. The duration of the rattle segments--14 and 100 ms (2/s), or 500 ms (1/s)--did not influence the likelihood of turning. Response latencies and durations proved quite similar for all stimuli. In Experiment 2, twenty-four infants heard continuous rattle sounds of four different durations: 1, 5, 10, and 20 s. They turned reliably to all stimulus durations; furthermore, the magnitude and temporal characteristics of head orientation responses did not differ for the four stimulus durations. These results suggest that the newborn's head orientation response may reflect a motor program that is initiated by auditory input and then executed in a similar fashion regardless of further stimulation.     

Trading relations in the perception of speech by 5-year-old children

Five-year-old children were tested for perceptual trading relations between a temporal cue (silence duration) and a spectral cue (F₁ onset frequency) for the “say-stay” distinction. Identification functions were obtained for two synthetic “say-stay” continua, each containing systematic variations in the amount of silence following the /s/ noise. In one continuum, the vocalic portion had a lower F₁ onset than in the other continuum. Children showed a smaller trading relation than has been found with adults. They did not differ from adults, however, in their perception of an “ay-day” continuum formed by varying F₁ onset frequency only. The results of a discrimination task in which the two acoustic cues were made to “cooperate” or “conflict” phonetically supported the notion of perceptual equivalence of the temporal and spectral cues along a single phonetic dimension. The results indicate that young children, like adults, perceptually integrate multiple cues to a speech contrast in a phonetically relevant manner, but that they may not give the same perceptual weights to the various cues as do adults.     

Spatial co-location and infants'' learning of auditory-visual associations

The role of spatial co-location between sight and sound in infants' cross-modal learning was examined in three experiments. Four-and 6-month-old infants were familiarized with a toy and an accompanying soundtrack. Across conditions, spatial congruity between sight and sound was varied. Following familiarization, infants were tested to determine under which conditions they learned to associate the toy with the sound. Results indicated age-related differences in how discrepant in location a sight and sound could be for infants to form a cross-modal association based on the amodal invariant of co-location. Specifically, 4-month-olds formed cross-modal associations under conditions of less precise co-location than did 6-month-olds. Parallel improvements in infants' sound localization abilities across this age span are likely a contributing factor to the observed developmental trend in cross-modal learning.     

Development of the perception of musical relations: semitone and diatonic structure

In the present research we examined the development of sensitivity to two musical relations significant in Western tonal music, the semitone and diatonic structure. Infants and preschool children were tested for their detection of a semitone change in any position of a five-note melody. Two standard melodies were used, one composed of diatonic tones only and the other containing a non-diatonic tone. In Experiment 1, children from 4 to 6 years of age were superior in detecting the semitone change in the diatonic context compared with the nondiatonic context. In Experiment 2, infants 9 to 11 months of age detected the semitone change in all positions, but their performance was not influenced by diatonic context. These findings indicate that infants and children can discriminate a semitone in a musical context and that the priority of diatonic structure emerges by 4 to 6 years of age.     

Perceptual equivalence of acoustic cues in speech and nonspeech perception

Trading relations show that diverse acoustic consequences of minimal contrasts in speech are equivalent in perception of phonetic categories. This perceptual equivalence received stronger support from a recent finding that discrimination was differentially affected by the phonetic cooperation or conflict between two cues for the /slIt/-/splIt/contrast. Experiment 1 extended the trading relations and perceptual equivalence findings to the /sei/-/stei/contrast. With a more sensitive discrimination test, Experiment 2 found that cue equivalence is a characteristic of perceptual sensitivity to phonetic information. Using “sine-wave analogues” of the /sei/-/stei/stimuli, Experiment 3 showed that perceptual integration of the cues was phonetic, not psychoacoustic, in origin. Only subjects who perceived the sine-wave stimuli as “say” and “stay” showed a trading relation and perceptual equivalence; subjects who perceived them as nonspeech failed to integrate the two dimensions perceptually. Moreover, the pattern of differences between obtained and predicted discrimination was quite similar across the first two experiments and the “say”-“stay” group of Experiment 3, and suggested that phonetic perception was responsible even for better-than-predicted performance by these groups. Trading relations between speech cues, and the perceptual equivalence that underlies them, thus appear to derive specifically from perception of phonetic information.     

Gender biases in children's appraisals of injury risk and other children's risk-taking behaviors

Children ages 6, 8, and 10 years were given tasks designed to assess their beliefs about risk of injury from activities. Children were asked to appraise the risk of injury for boys and girls engaging in various play behaviors and to judge the sex of the character in stories about children engaging in activities that result in injuries. Results revealed gender biases in children's appraisals of injury risk: Both boys and girls rated boys as having a lower likelihood of injury than girls even though the boys and girls were engaging in the exact same activities. Children also showed higher accuracy in identifying the sex of the character in stories of boys' injuries than girls' injuries, and accuracy improved with the participant's age. Overall, the results indicate that by the age of 6 years children already have differential beliefs about injury vulnerability for boys and girls. Although boys routinely experience more injuries than girls, children rate girls as having a greater risk of injury than boys. With increasing age, school-age children develop a greater awareness of the ways in which boys and girls differ in risk-taking activities that lead to injury outcomes.     

Developmental changes in associations between auditory-visual events

The goal of the present study was twofold: to examine the influence of two amodal properties, co-location and temporal synchrony, on infants' associating a sight with a sound, and to determine if the relative influence of these properties on crossmodal learning changes with age. During familiarization 2-, 4-, 6- and 8-month-olds were presented two toys and a sound, with sights and sounds varying with respect to co-location and temporal synchrony. Following each familiarization phase infants were given a paired preference test to assess their learning of sight-sound associations. Measures of preferential looking revealed age-related changes in the influence of co-location and temporal synchrony on infants' learning sight-sound associations. At all ages, infants could use temporal synchrony and co-location as a basis for associating an auditory with a visual event and, in the absence of temporal synchrony, co-location was sufficient to support crossmodal learning. However, when these cues conflicted there were developmental changes in the influence of these cues on infants' learning auditory-visual associations. At 2 and 4 months infants associated the sounds with the toy that moved in synchrony with the sound's rhythm despite extreme violation of co-location of this sight and sound. In contrast, 6- and 8-month-olds did not associate a specific toy with the sound when co-location and synchrony information conflicted. The findings highlight the unique and interactive effects of distinct amodal properties on infants' learning arbitrary crossmodal relations. Possible explanations for the age shift in performance are discussed.     

Mothers' Reactions to Children Misbehaving in Ways That Can Lead to Injury: Implications for Gender Differences in Children's Risk Taking and Injuries

A scenario methodology in which mothers imagined themselves and their school-age children in different home situations was used to examine mothers' reactions to sons and daughters when the children were misbehaving in ways that could, and sometimes did, result in injuries. Prior to injury, mothers predominantly expressed anger to sons and disappointment to daughters, focusing primarily on safety issues in response to daughters' misbehavior and discipline issues in response to sons' misbehavior. Once an injury resulted, mothers became concerned about their children, but the degree of concern was greater for injuries to daughters than to sons. Sons' risky misbehavior was attributed predominantly to nonmodifiable characteristics, whereas daughters' risky misbehavior was attributed to factors that a parent could expect to influence. Consistent with these attributions, mothers advocated active injury-prevention approaches to prevent injury recurrence to daughters, but did not believe that much else could be done to prevent injury recurrence to sons. Generally, the pattern of results support the notion that mothers expect more risky behavior of sons than of daughters, are more concerned about injuries to daughters than sons, and believe they can have greater influence on the risk-taking behavior of daughters than sons. Implications of these results for understanding gender differences in children's risk-taking and injuries are discussed.     

"Do as I say, not as I do": family influences on children's safety and risk behaviors

OBJECTIVE: Although there is considerable speculation that family-based socialization processes influence children's safety and risk behaviors, few studies have addressed this important issue. The present study compared the impact of parent practices and teaching about safety on children's current behaviors and their intended future behaviors when they reach adulthood. DESIGN AND MEASURES: Children 7 to 12 years of age were interviewed and asked to report on their parents' practices and teachings (discussions, expectations for children's behavior) regarding five common safety behaviors. As well, the children reported on their own current practices and how they intended to behave when an adult. When appropriate, they provided explanations about why their parents engage in fewer safety behaviors than they required of their children. RESULTS: Children's current behavior was best predicted by parental teaching, however, how children planned to behave when they were adults was best predicted by parents' practices. Children attributed less frequent safety behaviors by their parents than themselves to general attributes of adults and their parent having special skills that made the safety practices less necessary than was true for children. CONCLUSION: These results highlight family influences on children's adoption of safety and risk practices and support the notion of intergenerational transmission of risk behaviors.