Developmental changes in the understanding of temporal sequence

In 3 experiments, 4-, 5-, and 6-year-olds' ability to sequence events was examined. We hypothesized that children initially construct temporal sequences by relying on the organization of their world knowledge instead of inferring logical relations among actions. In the first experiment, children generated picture sequences of familiar and unfamiliar events in forward and backward order without having seen the pictures in their correct sequence. In the second experiment, children reconstructed previously seen sequences, and in the third experiment, children were shown forward and backward sequences and reconstructed them in the opposite direction. Across experiments, the same pattern of performance was found; familiar events in forward order were the easiest to sequence, then unfamiliar events in forward order, familiar events in backward order, and finally unfamiliar events in backward order. These results are discussed along with other findings suggesting a similar pattern of performance across a wide developmental age span.     

Developmental dyslexics show deficits in the processing of temporal auditory information in German vowel length discrimination

The present study investigated auditory temporal processing in developmental dyslexia by using a vowel length discrimination task. Both temporal and phonological processing were studied in a single experiment. Seven German vowel pairs differing in vowel height were used. The vowels of each pair differed only with respect to vowel length (e.g., /a/ vs. /a:/). In German, vowel length is characterized by temporal and spectral information. Three types of differences between long versus short vowels were varied: In the phonological condition, pairs of natural vowels were used, differing in their temporal as well as in their spectral content. In two temporal conditions, in contrast, a natural vowel was always combined with a manipulated one to keep spectral content of long and short vowels identical. Thus, the only distinguishing feature between the two vowels was temporal in nature. Vowels were embedded into monosyllabic pseudo-words and presented successively in a speeded same–different task. Twenty dyslexics and twenty age-matched controls participated in the experiment. In both groups, discrimination accuracy decreased with increasing vowel height in the two temporal conditions. This result is consistent with former findings on the relevance of temporal information for vowel length identification in German and extends this topic to cover discrimination demands. In the phonological condition, groups did not differ in discrimination accuracy. In both temporal conditions, however, dyslexics performed worse than controls. These results suggest that developmental dyslexia is associated with impairments in processing basic acoustic parameters of the speech signal, in particular, with a deficit in temporal processing.     

Organizational processes in infants' perception of auditory patterns

Infants 9-11 months of age were tested for their discrimination of changes in the melodic contour (direction of successive pitch changes) of brief melodies in the context of discernible variations in key (different absolute frequencies, same intervals) or interval size (different absolute frequencies and frequency ratios, same contour). Infants detected contour changes in both variable contexts, suggesting that they categorize sequences of sounds on the basis of global, relational properties such as melodic contour. Implications of such processing strategies for infants' perception of running speech are considered.     

The development of auditory temporal acuity in children

The development of auditory temporal acuity was studied in 56 children aged 6-12 years and compared with that of 8 adults. Acuity was measured by determining the minimum detectable duration of a brief cessation in a noise band with the 2-alternative forced-choice method. For detection of gaps in a broadband noise, acuity improved significantly with age and reached adult values by 11 years. The minimum detectable duration was significantly shorter at higher levels of the noise. For narrow-band noises, acuity also improved significantly with age and depended on the center frequency of the band. The improvement in temporal acuity with age was attributed to the development of sensory processes and not to age-related changes in nonsensory factors.     

The perception of time relations in auditory tempo discrimination

European starlings (Sturnuis vulgaris) were trained to discriminate between pulses of sound presented at rates (tempos), for different birds, of 4/sec and 8/sec or 8/sec and 16/sec in a two-alternative choice task. Once the discrimination was learned, psychometric functions and bisection points were determined for tempos between the standards. Then the starlings were transferred to a new discrimination, which either maintained or changed the relationship between response keys and tempo (relational or nonrelational transfer). The results showed that the starlings generated psychometric functions for tempo with properties much like those found for discrimination of single time intervals. Also, the starlings transferred the tempo discrimination faster under the relational than the nonrelational condition. In general, starlings-like human and other nonhuman animals-perceive temporal structures as invariant over proportional changes in the duration of structural elements.     

Developmental changes in hemispheric independence

In this research, we questioned whether children's relative inability to use the 2 cerebral hemispheres independently contributes toward their difficulty with the simultaneous execution of conflicting tasks. 2 naming tasks were simultaneously presented to either 1 visual field/hemisphere combination (unilateral) or were divided between visual fields/hemispheres (bilateral). We predicted that bilateral presentation would improve performance by insulating these conflicting tasks from mutual interference and that there would be a developmental shift in the size of the advantage for bilateral presentation. This hypothesis was confirmed in a sample of 120 children (N = 40 per group). Older children (12- and 14-year-olds) named more items when they were presented bilaterally, rather than unilaterally, when conflicting inputs were directed to different hemispheres. Younger children (10-year-olds) displayed no advantage for bilateral presentation regardless of whether conflicting tasks were projected to the same hemisphere or different hemispheres. The fact that 10-year-olds did not benefit from division of conflicting inputs between the hemispheres was interpreted as a symptom of their relative inability to use the hemispheres independently.     

Developmental change in infants' perception of correlations among attributes

The perception of relational information such as the correlation or co-occurrence among features should play a central role in abilities ranging from the perception and recognition of a simple pattern or object to the formation of a category. 4 experiments were conducted to examine developmental change in 4-, 7-, and 10-month-old infants' perception of correlations among attributes. The results suggested a developmental progression in infants' processing of simple correlational information, ranging from the processing of independent featural information only at 4 months, the perception of relations among features of a single pattern at 7 months, to the abstraction of invariant relations from a category at 10 months.     

Effects of auditory perception training on reading achievement

This study investigated the effect of an auditory training programme with backward readers who were also deficient in one or more auditory perceptual subskills. Thirty subjects were randomly assigned to one of three groups. The experimental group received a nine hour taped programme devised by the experimenter and designed to teach the skills of auditory discrimination, memory, analysis and synthesis and auditory-visual integration. The comparison group listened to stories on tape for the same duration as the experimental group, while the third group served as a control merely being tested at the beginning and at the end of the experiment. It was found that although the training programme significantly improved the performance of the experimental group over the other two groups on a total auditory perceptual test, there was no corresponding improvement in reading, on word recognition or comprehension tests. The particular auditory subskills which appeared amenable to training were auditory discrimination (rhyme) and auditory synthesis (blending and closure).     

Developmental differences in visual and auditory processing of complex sentences

Children aged 8 through 11 (N = 250) were given a word-by-word sentence task in both the visual and auditory modes. The sentences included an object relative clause, a subject relative clause, or a conjoined verb phrase. Each sentence was followed by a true-false question, testing the subject of either the first or second verb. Participants were also given two memory span measures: digit span and reading span. High digit span children slowed down more at the transition from the main to the relative clause than did the low digit span children. The findings suggest the presence of a U-shaped learning pattern for on-line processing of restrictive relative clauses. Off-line accuracy scores showed different patterns for good comprehenders and poor comprehenders. Poor comprehenders answered the second verb questions at levels that were consistently below chance. Their answers were based on an incorrect local attachment strategy that treated the second noun as the subject of the second verb. For example, they often answered yes to the question "The girl chases the policeman" after the object relative sentence "The boy that the girl sees chases the policeman." Interestingly, low memory span poor comprehenders used the local attachment strategy less consistently than high memory span poor comprehenders, and all poor comprehenders used this strategy less consistently for harder than for easier sentences.     

Developmental changes in ideas about lying

Videotaped stories depicting deliberate lies and unintentionally untrue statements were presented to 200 subjects evenly divided into the following age groups: 5, 8, 9, and 11 years and adult. Definitions of lying were seen to change gradually over this age range. Adults were more lenient than children in their moral evaluations of all the statements. All age groups rated a guess that did no harm as better than one that caused trouble, and they all judged selfishly motivated lies to be worse than both unintended falsehoods and "jocose" lies that aimed to please the listener. 11-year-olds tended to justify the prohibition against lying in terms of trust and fairness, whereas younger children cited authority's punitive sanctions.     

Temporal resolution of auditory perception in relation to perception, memory, and language skills in typical children

This study examined temporal resolution of auditory perception (TRAP) in relation to speech perception and phonological working memory in one experiment and in relation to measures of rapid naming, understanding of grammatical contrasts, and phonological awareness in a second experiment. In the TRAP test, 6- to 9-year-old children discriminated four pairs of two sine tones, 878 Hz and 1350 Hz, presented in blocks with stepwise decreasing interstimulus intervals from 256 ms to 8 ms. In Experiment 1, weak but significant correlations between TRAP and speech perception and phonological working memory were found, as well as a significantly lower TRAP performance by girls. Experiment 2 indicated a significant relation between TRAP and the phonological awareness task. The results give qualified support to the notion of a weak relationship between TRAP and speech perception and language skills among typical children. However, the gender differences in TRAP performance, the limited variance explained by the regression models, and the finding that only one of the language parameters correlated with TRAP do not support the notion of a causal relationship between language skills and TRAP. The possibility that TRAP is connected to general neurological maturation rather than specifically to language abilities is discussed.     

Developmental changes in children's choices of practice strategies

This study investigated children's choices of deliberate practice strategies. Six-to 11-year-olds (n = 85) were presented with three outwardly similar motor tasks that varied only in the precision of the motor response required to succeed. Children then had the opportunity to practice these tasks before a “test” in which they had to complete all three tasks in the fastest overall time. While children of all ages spent relatively more time practicing the hardest task, only 10- and 11-year-olds scored more successes on the hardest task than the other tasks during the initial practice period. After verbal instruction, however, children of all ages scored more successes on the hardest task during practice, and younger children became more likely to persevere with the hardest task rather than switching tasks after a success. Children's practice choices may vary as a function of age and verbal instruction.     

Developmental changes in the comparison of decimal fractions

Learning about decimal fractions is difficult because it requires an extension of the number concept built on natural numbers. The aim of the present study was to investigate developmental changes in children's misconceptions in decimal fraction processing. A large sample of children from Grades 3 to 6 performed a numerical comparison task on different categories of pairs of decimal fractions. The success rate and the type of error they made varied with age and categories. We distinguished the impact of the value of the digits from the impact of the length of the fractional part on children's pattern of responses. Although both kinds of impact affected the success rate, the digit values had a stronger impact and were mastered later than the length. Our results also showed that a zero just after the decimal point was understood better and earlier than a zero at the end of the fractional part of a number. Cluster analysis was conducted to determine groups of children who answered similarly regarding the response type across the various categories of decimal fractions. To interpret the data the conceptual change framework was used.     

Developmental changes and socioeconomic differences in mother-infant picturebook reading

Picturebook reading is a common form of interaction between parents and young children. This study examined developmental changes and socioeconomic differences in picturebook interactions of motherinfant Argentine dyads. 21 middle and 18 low SES mothers with their 12 to 24 months-old infants interacting with two different books, were observed. It was found that mothers of both SES groups adjusted the level of their demands not only to the task requirements (books) but also to the age of the infant. However, it was also found that the style of the interaction was different depending on the SES of the mother-infant pair. A more demanding and elaborated maternal language along with a linguistically more competent child were found in the middle SES group.     

Visual and auditory temporal processing, cross-modal transfer, and reading

The present study reexamined the relevance of auditory and visual cross-modal matching to reading ability, an issue first addressed in a seminal study by Birch and Belmont (1964). By presenting all patterns to be matched as temporal sequences of tones and lights, including intramodal as well as cross-modal conditions, and covarying memory, three problems with the Birch and Belmont design were corrected. Results showed that poor readers had difficulty in perceiving temporal patterns generally: They did worse than good readers not only on cross-modal conditions but also on intramodal ones. These results were replicated in two tasks. Nonetheless, hierarchical regressions provided some indication that cross-modal abilities themselves are relevant to reading. For one of the two tasks, cross-modal performance contributed to the prediction of reading ability over and above intramodal performance. Poor readers also showed slower response times--a factor that contributed marginally to the prediction of reading independent of temporal processing.     

Developmental changes in uncertainty monitoring during an event recall task

The present study was conducted to examine developmental progression in children’s metacognitive monitoring competencies in the context of a complex memory task. 7- and 9-year-olds rated their confidence after answering questions in two different question formats (unbiased and misleading) and two different question types (answerable and unanswerable). Feeling-of-knowing judgments were gathered for questions that had previously been answered with “don’t know.” The results showed that children from both age groups appropriately differentiated between correct and incorrect answers to unbiased questions in their confidence judgments, between answerable and unanswerable questions, and appropriately showed lower confidence levels in their confidence judgments than in their feeling-of-knowing judgments. 9-year-olds proved to be further able to discriminate metacognitively between correct and incorrect answers to misleading answerable questions in their confidence judgments while 7-year-olds were not. The comparison of feeling-of-knowing judgments before correct and incorrect recognition indicated that metacognitive differentiation at the lower end of the uncertainty–certainty continuum posed problems for these age groups. The observation of an adult confederate modeling appropriate metamemory monitoring did not improve children’s metacognitive performance.