Attending to spatial locations: a developmental study

In 2 experiments, 7- and 8-year-old children and college students performed a letter-detection task in which reaction time was the dependent variable. Expectancy was manipulated by varying the probability the stimulus would appear at the center of an imaginary circle rather than along the perimeter. Although both age groups responded consistently faster to stimuli presented in expected locations than to stimuli presented in unexpected locations, this expectancy effect was larger for the children than it was for the college students. In a third experiment, these results were replicated using a luminance-detection task with 5-year-olds, 8-year-olds, and college students as subjects. It was concluded that children as well as adults are able to expand or contract the breadth of their attentional focus in accordance with task demands and that there is a developmental change in the efficiency with which a stimulus presented in an otherwise empty field can be located. Furthermore, it was suggested that children may be more disrupted by the occurrence of an unexpected event than adults are.     

The role of stimulus salience in young children's ability to discriminate two-dimensional rotations: Reflections on a paradigm

Children's ability to discriminate reflections and rotations of visual stimuli was examined within the confines of a mental rotation task. It was hypothesized that success would be affected by both characteristics of the stimulus and by the subtlety of the discrimination required. Forty 3- to 4-year-old children were directed to mentally rotate a stimulus a given number of degrees and to discriminate the appearance of the rotated stimulus from among a set of alternatives. Four stimuli differing in the number of visual orientation cues were utilized across 24 trials. A significant effect was found for number of orientation cues, and data indicated the difficulty children experienced detecting reflections, a task which bears close resemblance to the yes/no option in prototypic rotation studies. Children were only successful with a limited range of stimuli when discrimination of a reflected foil was not required. Results are discussed in light of discrepant findings about children's kinetic imagery ability and the advisability of using this particular paradigm with young Children.     

Habituation of infants' cardiac response to speech stimuli

In an attempt to explore the relation between the amount of variability in a stimulus and rate of habituation to that stimulus, 4 groups of infants 4 1/2--5 1/2 months of age were presented with repeated speech stimuli which were synthesized exemplars of [baba], natural exemplars of [baba] or [kaba], or novel syllables of each trial. Infants' cardiac responses to the auditory stimuli were recorded, and the number of trials to a proportional criterion of habituation of the heart-rate decelerative response was determined. Infants were found to habituate most rapidly to the synthesized [baba] stimulus which remained constant across trials and least rapidly to the speech syllables which changed from trial to trial.     

An information-processing analysis of children's accuracy in predicting the appearance of rotated stimuli

Children's ability to discriminate reflections and rotations of visual stimuli was examined using a kinetic imagery task. It was hypothesized that success would be related to the number and placement of orientation markers on the stimuli, as well as whether or not reflections had to be discriminated from simple rotations. 40 4- and 5-year-old children were directed to imagine how a stimulus would look if rotated to a specified location and asked to indicate the appearance of the reoriented stimulus by selecting the correct option from a number of foils. 48 of the items required only discrimination of a reoriented stimulus. The other 48 also required discrimination of a reflection of the reoriented stimulus. Stimuli differed in the number of orientation cues on the edges of the figures. Results revealed that prediction accuracy was associated with the existence of orientation markers on the stimuli, as well as age, sex, type of discrimination, and several interactions among the variables. Findings were discussed in comparison to a priori predictions based on an analysis of how children might use orientation information when performing mental rotation tasks.     

Children's reasoning about disclosing adult transgressions: effects of maltreatment, child age, and adult identity

A total of two hundred ninety-nine 4- to 9-year-old maltreated and nonmaltreated children of comparable socioeconomic status and ethnicity judged whether children should or would disclose unspecified transgressions of adults (instigators) to other adults (recipients) in scenarios varying the identity of the instigator (stranger or parent), the identity of the recipient (parent, police, or teacher), and the severity of the transgression ("something really bad" or "something just a little bad"). Children endorsed more disclosure against stranger than parent instigators and less disclosure to teacher than parent and police recipients. The youngest maltreated children endorsed less disclosure than nonmaltreated children, but the opposite was true among the oldest children. Older maltreated children distinguished less than nonmaltreated children between parents and other types of instigators and recipients.     

The Effects of a Programed Textbook on Achievement Under Three Techniques of Instruction

The experiment examined the relationship among several variables affecting extra-dimensional (ED) shift performance. Children and adults were trained to one of three criteria and given one of two ED shifts. All tasks required S to choose one of two colored geometric forms projected on a screen. The results are: (a) older Ss made fewer errors in training and transfer than younger Ss; (b) overtraining did not facilitate the ED shift wherein stimuli remained the same from training to transfer for the adults, but it did for the 7- and 8-year-old children; (c) overtraining inhibited the performance of the 5- and 6-year-old Ss given this ED shift; (d) overtraining neither facilitated nor inhibited the ED shift wherein stimuli changed from training to transfer. An interpretation was given in terms of verbal labeling, discrimination of change, perservative errors, and task difficulty.     

Visual information-processing speed in reflective and impulsive children.

A backward-masking procedure was used to measure the rate of visual information processing in 8- and 10-year-old reflective and impulsive children. The test stimulus (TS) and the masking stimulus (MS) which followed it were presented tachistoscopially. The subject's information-processing threshold was defined as the next highest TS-MS interval above the interval where at least 3 of the 4 TSs were incorrectly identified. Reflective children were significantly faster than impulsive children at processing information. This finding was related to research indicating that reflective and impulsive children employ similar cognitive strategies; it was suggested that performance differences between these children might be related to reflective children employing their strategies with more adequate information.     

The development of audiovisual speech perception in Mandarin-speaking children: Evidence from the McGurk paradigm

The developmental trajectory of audiovisual speech perception in Mandarin-speaking children remains understudied. This cross-sectional study in Mandarin-speaking 3- to 4-year-old, 5- to 6-year-old, 7- to 8-year-old children, and adults from Xiamen, China (n = 87, 44 males) investigated this issue using the McGurk paradigm with three levels of auditory noise. For the identification of congruent stimuli, 3- to 4-year-olds underperformed older groups whose performances were comparable. For the perception of the incongruent stimuli, a developmental shift was observed as 3- to 4-year-olds made significantly more audio-dominant but fewer audiovisual-integrated responses to incongruent stimuli than older groups. With increasing auditory noise, the difference between children and adults widened in identifying congruent stimuli but narrowed in perceiving incongruent ones. The findings regarding noise effects agree with the statistically optimal hypothesis.     

Visual and verbal processes involved in the development of picture-recognition skills

4-5-year-old, 6-7-year-old, and 8-9-year-old children were given picture-recognition tasks in which recognition stimuli were systematically varied with respect to familiarization stimuli. Subjects were required either to verbalize or remain silent during familiarization and to identify either central figure only or whole picture recognition. Results suggested that (a) young children base recognition primarily on central figure whereas older children are more likely to utilize the entire stimulus array, and (b) younger children are more likely than older children to use spoken labels as a basis for recognition when they verbalize during familiarization.     

Oddity learning in the pigeon: Effect of negative instances,correction, and number of incorrect alternatives

Pigeons have difficulty learning a standard oddity task involving two colors and three stimulus positions. In Experiment 1, performance on standard noncorrection trials was compared with performance on (1) rerun correction trials in which errors resulted in trial repetition, (2) noncorrection trials with added “negative instance” trials involving presentation of three stimuli, all of which matched, and (3) a combination of correction and added negative instance trials. Results indicated that negative instances, but not correction trials, significantly facilitated oddity performance. In Experiment 2, Phase 1, number of stimulus positions lit (three or five) was factorially manipulated with number of positions on which the odd stimulus could appear (three or five). An increase in number of positions lit, but not number of positions that could be odd, facilitated performance. In Phase 2, birds transferred from trials with five positions lit to four positions lit performed significantly better than controls; but in Phase 3, the same birds did not perform significantly better than controls when transferred to trials with three positions lit. In both experiments, analysis of performance as a function of response position indicated better performance at the end of each display than in the middle. These results, together with the group performance differences in Experiment 2, suggest that oddity learning in pigeons involves a size, or number, discrimination.     

Perception of gated, highly familiar spoken monosyllabic nouns by children with and without learning disabilities

A forward-gating procedure employing highly familiar monosyllabic words was used in auditory testing of age- and gender-matched children with learning disabilities and normally achieving children aged 8 to 11 years. The portion of the word presented, or "gate," was longer on each successive trial. Nondisabled children identified an average of one more word than the children with learning disabilities, but the mean duration required for word identification did not differ between groups. Better receptive vocabulary scores were associated with identification of words at shorter durations only among the children with learning disabilities. The two groups of children had similar numbers of different meaningful-word and different non-word incorrect responses. The children with learning disabilities exhibited poorer fine-grained auditory discrimination than a control group of nondisabled children. The study concluded that auditory closure skills for the gating task were as good among children with learning disabilities as among nondisabled children, but that sensory discrimination problems may contribute significantly to the learning difficulties of the former group.     

Children's intuitive mathematics: the development of knowledge about nonlinear growth

This study is concerned with the development of children's intuitive understanding of nonlinear processes. The ability to estimate linear and exponential growth was examined in 7-, 9-, 11-, and 13-year-old children and adults (N=160). Whereas linear growth was judged correctly at all ages, estimations of exponential growth were in line with mathematically correct values only in 13-year-olds and adults. However, 9-year-olds already judged the result of exponential growth as being significantly higher than that of linear growth, and even a remarkable proportion of 7-year-olds showed such discrimination between the two types of functions. Results point to the existence of an early intuitive knowledge about the characteristics of nonlinear growth, long before those functions are taught in school.     

Emerging Integration of Sequential and Suprasegmental Information in Preverbal Speech Segmentation

5 studies examined contributions of syllable-ordering and rhythmic properties of syllable strings to 6- and 9-month-old infants' speech segmentation. A pair of methods measuring complementary properties of representational units was used: a noise detection task sensitive to perceived cohesiveness of pairs of syllables, and a discrimination maintenance task sensitive to compactness of representations of syllable pairs. For 9-month-olds, results show that a key pair of syllables was represented as a unit when the grouping of these syllables was supported by correlated regularities of ordering and rhythm in the set of stimulus strings, but not when such grouping was supported by only rhythmic or only syllable-ordering regularity. For 6-month-olds, results show that a key pair of syllables was represented as a unit whenever grouping was supported by rhythmic regularity in the stimulus strings, regardless of whether syllable-ordering regularity was also present. Thus, whereas 9-month-olds appear to be capable of integrating sequential and suprasegmental information in forming wordlike (multisyllabic) phonological percepts, 6-month-olds are not. The emergence of integrative abilities portends increased efficiency in speech processing and may contribute to the formation and use of an initial lexicon.     

日本高级汉语学习者汉语轻声韵律习得偏误分析

本文研究了汉语水平较高的日本学生习得普通话轻声时的韵律偏误,发现日本学生产出的轻声音节存在以下三方面问题：（一）调型方面,基频曲拱偏平,升降幅度不够;基频曲线后半段常有轻微抬升;T3后的轻声音节常常被读为降调。（二）调域方面,四声后的轻声音节都存在调域偏窄问题,其中T1、他后尤其严重。（三）时长方面,不同声调后轻声音节存在不同程度的时长过长问题,尤以T3后为最,甚至超过T3音节。     

Temporal discrimination using different feature-target intervals in classical conditioning of the rabbit’s nictitating membrane response

In a typical conditional discrimination, a target stimulus (X) is reinforced during one feature cue (A→X+), but not during another feature cue (B→X−). The present experiments used only a single “feature” cue (a 66-sec tone). On half of the trials, the target stimulus (a 400-msec light) was paired with the reinforcer when the feature-target interval was one duration (e.g., 5 sec). On the remaining trials, the interval was different (e.g., 45 sec), and the target stimulus was presented without the reinforcer. All the animals acquired this temporal discrimination, and subsequent testing with other feature-target intervals yielded generalization-like gradients. These results provide solid evidence that each portion of a feature cue is encoded in a distinctive fashion. Had temporal encoding not occurred, the feature cue would have been just as ambiguous a predictor of the reinforcer as was the target stimulus, and discrimination would not have been possible. The integration of real-time temporal encoding mechanisms into models of conditional discrimination is discussed.     

Syllable-based reading improvement: Effects on word reading and reading comprehension in Grade 2

This study examined the effects of a syllable-based reading intervention for German second graders who demonstrated difficulties in the recognition of written words. The intervention focused on fostering word reading via syllable segmentation. The materials consisted of the 500 most frequent syllables typically read by 6- to 8-year-old children. The aims were to practice phonological recoding, consolidate orthographic representations of syllables, and routinize the access to these representations. Compared to children randomly assigned to a wait-list group, poor readers in the treatment condition showed significant improvements in standardized measures of phonological recoding, direct word recognition, and text-based reading comprehension after the 24-session intervention. Poor readers in the treatment condition also showed greater improvements in development of word recognition compared to children with efficient word recognition skills. The results provide evidence that a syllable-based reading intervention is a promising approach to increase struggling readers’ word recognition skills, which in turn will improve their reading comprehension.     

Development of categorical speech perception in Mandarin-speaking children and adolescents

Although children develop categorical speech perception at a very young age, the maturation process remains unclear. A cross-sectional study in Mandarin-speaking 4-, 6-, and 10-year-old children, 14-year-old adolescents, and adults (n = 104, 56 males, all Asians from mainland China) was conducted to investigate the development of categorical perception of four Mandarin phonemic contrasts: lexical tone contrast Tone 1-2, vowel contrast /u/−/i/, consonant aspiration contrast /p/−/p^h/, and consonant formant transition contrast /p/−/t/. The results indicated that different types of phonemic contrasts, and even the identification and discrimination of the same phonemic contrast, matured asynchronously. The observation that tone and vowel perception are achieved earlier than consonant perception supports the phonological saliency hypothesis.     

The nature of the phonological processing in French dyslexic children: evidence for the phonological syllable and linguistic features' role in silent reading and speech discrimination

This study investigated the status of phonological representations in French dyslexic children (DY) compared with reading level- (RL) and chronological age-matched (CA) controls. We focused on the syllable’s role and on the impact of French linguistic features. In Experiment 1, we assessed oral discrimination abilities of pairs of syllables that varied as a function of voicing, mode or place of articulation, or syllable structure. Results suggest that DY children underperform controls with a ‘speed-accuracy’ deficit. However, DY children exhibit some similar processing than those highlighted in controls. As in CA and RL controls, DY children have difficulties in processing two sounds that only differ in voicing, and preferentially process obstruent rather than fricative sounds, and more efficiently process CV than CCV syllables. In Experiment 2, we used a modified version of the Colé, Magnan, and Grainger's (Applied Psycholinguistics 20:507–532, 1999) paradigm. Results show that DY children underperform CA controls but outperform RL controls. However, as in CA and RL controls, data reveal that DY children are able to use phonological procedures influenced by initial syllable frequency. Thus, DY children process syllabically high-frequency syllables but phonemically process low-frequency syllables. They also exhibit lexical and syllable frequency effects. Consequently, results provide evidence that DY children performances can be accounted for by laborious phonological syllable-based procedures and also degraded phonological representations.     

Tests of a Dynamic Systems Account of the A-not-B Error: The Influence of Prior Experience on the Spatial Memory Abilities of Two-Year-Olds

Recently, Smith, Thelen, and colleagues proposed a dynamic systems account of the Piagetian "A-not-B" error in which infants' errors result from general processes that make goal-directed actions to remembered locations. Based on this account, the A-not-B error should be a general phenomenon, observable in different tasks and at different points in development. Smith, Thelen, et al.'s proposal was tested using an A-not-B version of a sandbox task. During three training trials and three "A" trials, 2-year-olds watched as a toy was buried in a sandbox at Location A. Following a 10-s delay, children searched for the object. Across five experiments, children's (total N = 92) performance on the A trials was accurate. After the A trials, children watched as a toy was hidden at Location B, 8 to 10 inches from Location A. In all experiments, children's searches after a 10-s delay were significantly biased in the direction of Location A. Furthermore, this bias toward Location A decreased with repeated trials to Location B, as well as when children completed fewer trials to Location A. Together, these data suggest that A-not-B-type errors are pervasive across tasks and development.     

Prolonged duration of the “novelty effect” following prolonged exposure to a single discriminandum

Rats were exposed for approximately 1 month to a single stimulus mounted on the home cage wall. During discrimination training, half of the Ss had the exposed figure as the positive stimulus and half the exposed figure as the negative stimulus. Control Ss had no pattern mounted on the wall. The results indicate that when the exposed figure was the positive stimulus, the Ss made significantly more errors than the control Ss. but when the exposed figure was the negative stimulus, the Ss made significantly fewer errors. These results are consistent with the exploratory literature, which suggests that exposure to a stimulus will reduce the invitational properties of that stimulus relative to a more novel stimulus and thereby will affect the probability of selecting one stimulus over another, at least for a period of time, in a discrimination task.