Waiting to Use a Symbol: The Effects of Delay on Children's Use of Models

To use a symbol to solve a problem, children must achieve representational insight; they must realize that the symbol stands for its referent. Moreover, they must keep this relation in mind as they attempt to use the symbol. The present studies investigated the achievement and maintenance of representational insight. 3-year-olds were asked to use a scale model of a room to find a toy hidden in the room. In Study 1a, children first watched as a small toy was hidden in the model. They then waited either 20 sec, 2 min, or 5 min before attempting to find a similar, larger toy that was hidden in the corresponding place in the room. All children experienced all delay intervals; three groups experienced the delays in different orders. There was a dramatic effect of delay order. The children who experienced the 20-sec delay on their first trial generally performed well throughout the 6 trials, but the children who experienced a 5-min delay first almost always failed to find the toy in the room, even on subsequent trials with shorter delays. Additional studies revealed that the negative effects of the initial long delay could be overcome by providing reminders of the model and its relevance (Studies 2 and 3) or by giving children prior experience in using the model (Study 4). The results indicate that keeping a symbol-referent relation in mind can be difficult for 3.0-year-old children. This research is discussed in terms of the importance of maintaining representational insight.     

Mind what mother says: narrative input and theory of mind in typical children and those on the autism spectrum

In 2 studies mothers read wordless storybooks to their preschool-aged children; narratives were analyzed for mental state language. Children's theory-of-mind understanding (ToM) was concurrently assessed. In Study 1, children's (N=30; M age 3 years 9 months) ToM task performance was significantly correlated with mothers' explanatory, causal, and contrastive talk about cognition, but not with mothers' simple mentions of cognition. In Study 2, the same pattern was found in an older sample of typically developing children (N=24; M age 4 years 7 months), whereas for children on the autism spectrum (N=24; M age 6 years 7.5 months), ToM task performance was uniquely correlated with mothers' explanatory, causal, and contrastive talk about emotions.     

不同语言能力幼儿在三种错误信念任务中的表现

本研究采用了实验的方法,以言语、非言语性任务,意外转移与表征变化任务为变量,考察了不同语言能力的88名3-4岁幼儿的错误信念理解能力。研究结果发现,降低错误信念任务对语言能力的要求并不能改变幼儿在错误信念理解上的年龄特征;在3岁和4岁两个年龄组中,语言能力超常的幼儿在各项实验任务上的表现均好于语言能力一般的幼儿。     

The use of minimization to form comparison groups in educational research

Randomized controlled trials in educational research tend to be small. Small trials can have large, chance, imbalances in important covariates. For studies with sample sizes greater than 50, chance imbalances can be corrected using analysis of covariance; for small trials, however, statistical power is maximized if the trial is balanced and analysis of covariance is used in the analysis. The aim of the present study was to discuss methods of improving covariate balance in trial design and to demonstrate the method of minimization. Using an exemplar of a cluster or class‐randomized trial with 29 classes, we employed minimization to achieve covariate balance. Minimization achieved good balance on four prognostic variables. Many trialists in education use restricted forms of allocation, including pairing or stratified randomization. These approaches have disadvantages. Another approach rarely used in educational research is minimization. Minimization uses a simple arithmetic algorithm to produce balanced groups across a number of important covariates and should be more widely used in educational and psychological research.     

Comprehension of Novel Communicative Signs by Apes and Human Children

Forty-eight young children (2.5 and 3.0 years old) and 9 great apes (6 chimpanzees and 3 orangutans) participated in a hiding- finding game. An adult human experimenter (the Hider) hid a reward in 1 of 3 opaque containers aligned on a wooden plank. Another adult experimenter (the Communicator) attempted to help the subject find the reward by giving 1 of 3 types of communicative sign: (1) Pointing, For which she placed her hand directly above the correct container with index finger oriented down; (2) Marker, for which she paced a small wooden block on top of the correct container; and (3) Replica, For which she held up a perceptually identical duplicate of the correct container. At both ages, children were above chance in this finding game with all 3 types of communicative sign, with pointing being easiest Cbecause they knew it prior to the experiment), Marker being next easiest, and Replica being most difficult. In contrast, no ape was above chance for any of the communicative signs that it did not know before the experiment (some had been trained in the use of the marker previously, and one knew pointing), nor was group performance above chance for any of the signs despite the fact that apes experienced three times as many trials as children on each sign. Our explanation of these results is that young children understand the communicative intentions of other persons—although they may have more difficulty comprehending the exact nature of those intentions in some cases—whereas apes treat the behavioral signs of others as predictive cues only (signals). This may be because apes do not Perceive and understand the communicative intentions of others at least not in a human-like way.     

Spatial localization of a goal: Beacon homing and landmark piloting by rats on a radial maze

We performed six experiments in order to examine the ability of rats to use moving beacons and landmarks as cues to the location of reward on an eight-arm radial maze. In Experiments 1–4, the cues and goals were moved before each trial, and groups in which a single beacon was placed on the rewarded arm, a single landmark indicated that reward was on the arm immediately to the left of a landmark, or two landmarks were placed on each side of the reward arm were compared. The rats rapidly learned to track the reward in the beacon condition, failed to find the reward sooner than chance expectation with a single landmark, and did only slightly better than chance with two landmarks. In Experiments 5 and 6, the rats were trained in five trials per day, with the landmark and goal locations constant over daily rewarded trials, and in two extinction trials that were inserted among the rewarded trials. The rats found the goal arm at substantially better than chance expectancy with both one and two landmarks. Our results, in agreement with data from recent swimming pool experiments (A. D. L. Roberts & Pearce, 1998), show that rats will use the relationship between moving landmarks and a goal in order to find reward.     

Taking working memory training from the laboratory into schools

Working memory skills have been shown to be enhanced by adaptive training in several randomised controlled trials. Here, two field trials were conducted in which teachers administered working memory training to their own pupils in school. Twenty-two children aged 8–9?years participated in Trial 1. In Trial 2, 50 children aged 9–11?years with the lowest academic performance completed training. They were matched with a group of 50 children who were not trained. Following training, children in Trial 1 improved significantly in both trained and untrained working memory tasks, with effect sizes comparable to those reported in research studies. Improvements on the trained tasks in Trial 2 were comparable, and training was associated with significantly greater progress at school across the academic year in maths and English. These findings indicate that teacher-administered training leads to generalised and robust gains in working memory and educationally significant gains in academic performance.     

Limitations on reliability: regularity rules in the English plural and past tense

Two studies investigated 3- to 5-year-olds' trust in a reliable informant when judging novel labels and novel plural and past tense forms. In Study 1, children ( N = 24) endorsed the names of new objects given by an informant who had earlier labeled familiar objects correctly over the names given by an informant who had labeled the same objects incorrectly. In Study 2, children ( N = 24) endorsed novel names given by an informant who had earlier expressed the plural of familiar nouns correctly over one who had expressed the plural incorrectly. But children overwhelmingly endorsed the regular plural and past tense forms of new words provided by the formerly unreliable labeler (Study 1) or morphologist (Study 2) rather than irregular forms of those words provided by the formerly reliable informant.     

Specific intellectual deficits in children with early onset diabetes mellitus

27 children with early onset (less than 4 years) diabetes (EOD), 24 with late onset (greater than 4.0 years) diabetes (LOD), and 30 sibling controls were compared in their performance on tests of intellectual functioning and school achievement. The results indicated that children with EOD, particularly girls, scored lower than the other groups of diabetic children and siblings on tests of visuospatial but not verbal ability. Many of the children with EOD were also having difficulty at school, and a number were currently receiving special education. Diabetic children with earlier onset had more hypoglycemic convulsions than those with later onset. Regression analyses revealed that duration of illness, age of onset, and hypoglycemic convulsions significantly predicted spatial ability.     

Effects of varying trial distribution,intra- and extramaze cues,and amount of reward on proactive interference in the radial maze

Rats are typically less accurate in their arm selections in the radial maze over successive trials in a session (Roberts & Dale, 1981). In the present study, rats’ choice accuracy declined when such trials were separated by 2-min (massed) but not by 2-h (spaced) intertriai intervals. Changing intramaze visual/tactile arm stimuli (Experiments 1 and 3) or extramaze landmark stimuli (Experiment 4) between trials weakened the massed-trials effect, but changing the number of food pellets per arm, either alone or in conjunction with changes in intramaze cues (Experiments 2 and 3), did not. The rats also tended to avoid the spatial locations of their last four choices on a previous trial during their first four choices on a current trial, and more so with massed than with spaced trials. These findings indicate that intertriai proactive interference (PI) occurred only with massed trials and was weakened by changing intra- and extramaze cues between such trials.     

Enhancing the Development of Low-Birthweight, Premature Infants: Changes in Cognition and Behavior over the First Three Years

The Infant Health and Development Program is a randomized clinical trial to test the efficacy of educational and family support services and pediatric follow-up offered in the first 3 years of life on reducing the incidence of developmental delay in low-birthweight (LBW), preterm infants in 8 clinical sites ( N = 985). Effects of the intervention on cognitive and behavior problem scores over the 3 years are examined. Significant intervention effects were seen on cognitive scores at 24 and 36 but not 12 months of age; effect sizes were similar at both ages. These effects persist when controlling for earlier cognitive scores. At 24 and 36 months, behavior problem scores for the intervention group were significantly lower than for the follow-up group; the intervention was more efficacious for children with higher initial behavior problem scores. Results are discussed in terms of timing and targeting of services for LBW and disadvantaged children.     

Children's ability to make probability estimates: skills revealed through application of Anderson's functional measurement methodology

Functional measurement methodology was used to assess children's attention to the total number of alternative outcomes as well as the number of target outcomes when making probability estimates. In Study 1, first-, third-, and fifth-grade children were given the task of estimating on a simple, continuous but nonnumeric scale the probability of drawing a particular color of jelly bean from a bag containing either 1, 2, or 3 jelly beans of that color, and either 6, 8, or 10 jelly beans total. In Study 2, first- through fifth-grade children were given the task of estimating the likelihood that a bug would fall on a pot containing a flower when presented displays of planters containing either 2, 3, 4, or 5 pots with flowers, and 6, 8, or 10 pots total. In both studies, the children were exposed to each of the combinations of numerator and denominator across 3 replications. The results indicate that all age groups attend to variations in the denominator as well as to variations in the numerator, and, furthermore, that they attend to the interaction between these variables. This finding contrasts sharply with research that requires children to choose which of 2 containers offers the greater chance of yielding a target item in a blind draw. It is suggested that children possess the skill to make accurate probability estimates, but they are unaware that these estimates should always be made and used when comparing the probability of an event across trials. The findings are discussed in relation to the broader issue of the limitations of the choice paradigm as a means of investigating children's thinking.     

The effects of stimulus and task on preschoolers' ability to identify visual sequences

The effects of task and stimuli on the ability of 3- to 5-year-old preschoolers to identify simultaneously presented visual sequences was further assessed. A same-different task was compared to a matching task and familiar pictorial stimuli were compared to unfamiliar letters. Materials consisted of 3 element strings with 1 element repeated; both the standard and alternative(s) remained in full view on each of 25 trials. Older children performed better than younger children. The same-different task was easier than the matching task; this effect was not maintained when the differential effects of chance in the 2 tasks were removed. This pictorial stimuli produced better performance than the letters and also interacted with the type of error made. Reversal errors occurred most often in all conditions, but other kinds of errors were more frequent in the letter than the picture condition. This was particularly true for the matching task. The use of reversal errors to the exclusion of all other error types was associated with high overall accuracy on visual sequence discriminations.     

The influence of cue type and configuration upon radial-maze performance in the rat

The influence of cue type and cue configuration on radial-maze performance in rats was examined in two experiments. In the first experiment, it was found that rats provided with both salient intramaze and extramaze cues acquired the task faster than rats given only one set of cues. No difference in acquisition was found between a group trained with intramaze cues alone and a group trained with extramaze cues alone. In a cue-preference test, it was found that groups that had been trained with extramaze cues, intramaze cues, or both sets of cues relied on extra-maze cues to avoid visited arms when given both types of cues concurrently. When all groups were transferred to intramaze-cue-alone trials, only the group that had been originally trained with extramaze cues alone showed any disruption. Also, during the second half of the intramaze-cue-alone trials, the arrangement of these cues was randomly changed on each trial. This disruption in cue configuration did not deleteriously affect performance in any of the three groups; all remained above chance performance, although the performance of the group originally trained with extramaze cues alone was inferior to that of the other two groups. In Experiment 2, groups of rats were trained on daily alternating trials under intramaze-cue-alone and extramaze-cue-alone conditions. For one group, the configuration of intramaze cues was altered randomly on each trial; the other group had intramaze cues always presented in the same configuration over trials. It was found that acquisition was more rapid on intramaze trials in the group given static configurations. Also, acquisition of the extramaze task was faster than the intramaze task in the group given variable intramaze cue configurations. No difference was found between the intramaze and extramaze conditions in the group given static intramaze cue configurations. These data suggest that a static cue configuration may influence radial maze performance, but is not a necessary condition for such performance.     

Fledgling Theories of Mind: Deception as a Marker of Three-Year-Olds' Understanding of False Belief

3 studies involving more than 70 3- and 4-year-olds were carried out in an effort to better secure an earlier but controversial set of findings interpreted as demonstrating that children younger than 4 already have a grasp of the possibility of false belief, and consequently deserve to be credited with some authentic if fledgling theory of mind. These studies, which relied on a measure of deceptive hiding rather than more familiar "unexpected change" procedures for indexing false belief understanding, all demonstrated that even the youngest of these subjects: (a) accurately anticipated the likely impact of their deceptive strategies on both the behaviors (Study 1) and beliefs (Study 3) of their opponents, and (b) were able to selectively employ these same methods of information management as a means of helping as well as hindering the efforts of others (Study 2).     

Assessment of progressively delayed prompts on guided skill learning in rats

We examined the controlling factors that allow a prompted skill to become autonomous in a discrete-trials implementation of Touchette’s (1971) progressively delayed prompting procedure, but our subjects were rats rather than children with disabilities. Our prompted skill was a left-right lever-press sequence guided by two panel lights. We manipulated (a) the effectiveness of the guiding lights prompt and (b) the presence or absence of a progressively delayed prompt in four groups of rats. The less effective prompt yielded greater autonomy than the more effective prompt. The ability of the progressively delayed prompt procedure to produce behavioral autonomy depended upon characteristics of the obtained delay (trial duration) rather than on the pending prompt. Sequence accuracy was reliably higher in unprompted trials than in prompted trials, and this difference was maintained in the 2 groups that received no prompts but yielded equivalent trial durations. Overall sequence accuracy decreased systematically as trial duration increased. Shorter trials and their greater accuracy were correlated with higher overall reinforcement rates for faster responding. Waiting for delayed prompts (even if no actual prompt was provided) was associated with lower overall reinforcement rate by decreasing accuracy and by lengthening trials. These findings extend results from previous studies regarding the controlling factors in delayed prompting procedures applied to children with disabilities.     

The Effects of the Spacing of Test Trials and Study Trials in Paired‐association Learning

The learning effects due to test and study trials after the initial presentation were examined in a paired‐associate learning paradigm. In Experiment 1 both the spacing and retention intervals were systematically varied. The results showed advantages of spacing for both test and study trials. However, the spacing function of test trials interacted significantly with the retention interval. At a short retention interval, the second recall was a decreasing function of spacing and paralleled closely the initial recall. As the retention interval increased, the spacing‐of‐test function assumed an inverted U‐shape. Performance after repeated studies was on the average better than after test trials. Experiment 2 confirmed that when an initial presentation was followed by two test trials, an increasing spacing interval between each successive test trial produced optimal long‐term performance. In the case where a second study trial was coupled with a test trial, a pattern with equal interval length was better than other spacing patterns. The proportion of test trials of the study list was also varied among groups of subjects. A higher proportion of test trials resulted in better final recall.     

Shuttlebox avoidance to intense white noise: Acquisition and the Kamin effect in rats

Experiment I demonstrated shuttlebox avoidance conditioning using intense white noise as a UCS. Ten rats were given 25 trials a day for 6 days. Escape latencies declined and avoidance responses increased over trial blocks. Experiment II provided support for a functional similarity between shock as a UCS and intense noise as a UCS by demonstrating the Kamin effect following incomplete shuttlebox training to noise. Separate groups of rats were given 25 trials followed by an additional 25 trials either 0, 1, 4, or 24 h later. The U-shaped Kamin effect was evident in the avoidance measure. A similar but inverted U-shaped function was obtained for the escape latency measure. Escape latencies were longer on retraining than on original training at 1 h but not at 0, 4, or 24 h after original training.     

Writing Dinosaur Large and Mosquito Small: Prephonological Spellers’ Use of Semantic Information

One influential theory of literacy development, the constructivist perspective, claims that young children believe that writing represents meaning directly and that the appearance of a written word should reflect characteristics of its referent. There has not been strong evidence supporting this idea, however. Circumventing several methodological concerns with previous studies, we examined written spellings of young children who did not yet use letters to represent the sounds of words, that is, prephonological spellers. We identified 38 prephonological spellers (M age = 4 years, 2 months) and measured the area of their writing productions. Prephonological spellers made significantly larger productions for words representing large objects than those representing small objects. This effect held true after controlling for the influences of other variables, including size of writing on previous trials and order of trial in a session. Our results suggest that young children sometimes use drawing-like features to communicate the meaning of words when writing.