A developmental comparison of identity and equivalence conservations

The developmental priority of identity conservation as contrasted with equivalence conservation theorized by Elkind (1967) was investigated using quantity and number conservation tasks. Subjects were 60 four-, five-, and six-year-old children of middle socioeconomic class background. All children received a battery of tasks which included qualitative identity, quantitative identity, and equivalence conservation of quantity and number problems. For the quantity battery, under the without justification condition, conditional probabilities and significant performance differences in the mean number of trials passed indicated that the order of acquisition of quantity tasks did conform to the hypothesized sequence: qualitative identity, quantitative identity, and equivalence conservation. No significant performance differences for number concepts were noted for both justification and without justification conditions. Scalogram analyses performed upon the combined quantity number task array indicated a scale or quasi-scale in the predicted order of difficulty. It was concluded that identity concepts develop prior to equivalence concepts when the content area is quantity conservation. In contrast, clear-cut conclusions cannot be made about number conservation.     

Single versus repeated assessments of infant abilities using the Bayley scales of infant development

An analysis of the score differences and characteristics achieved by 9- and 15-month-old infants tested twice with the Bayley Scales of Infant Development, one week apart, shows marked variations between what could be considered optimal estimates of ability and estimates of ability based on actual scores. There is approximately a 50% chance that an infant's actual Developmental Quotient from a single examination will differ from its optimal score by more than one standard deviation of the BSID. The fact that single test scores do not reliably estimate “true” capabilities reconfirms that a caveat be maintained concerning the use of single Bayley scores as baselines of longitudinal research or as outcome measures, but holds out the possibility that the usefulness of such scores as predictive of outcome measures can be improved over its present negligible status through repeated assessments.     

Visual statistical learning in the newborn infant

Statistical learning – implicit learning of statistical regularities within sensory input – is a way of acquiring structure within continuous sensory environments. Statistics computation, initially shown to be involved in word segmentation, has been demonstrated to be a general mechanism that operates across domains, across time and space, and across species. Recently, statistical leaning has been reported to be present even at birth when newborns were tested with a speech stream. The aim of the present study was to extend this finding, by investigating whether newborns’ ability to extract statistics operates in multiple modalities, as found for older infants and adults. Using the habituation procedure, two experiments were carried out in which visual sequences were presented. Results demonstrate that statistical learning is a general mechanism that extracts statistics across domain since the onset of sensory experience. Intriguingly, present data reveal that newborn learner’s limited cognitive resources constrain the functioning of statistical learning, narrowing the range of what can be learned.     

Heart rate conditioning in the newborn infant

In an attempt to condition heart rate in newborns, 21 infants were assigned to Conditioning, Random Control, and Backward Conditioning Groups. During training trials, the Conditioning Group received an eight-second tone (CS), a six-second ISI, and a ten-second presentation of glucose via nipple (UCS) that overlapped the last two seconds of tone. The Random Control Group received tones at the same intertrial intervals as the Conditioning Group, but glucose varied randomly. The Backward Conditioning Group received glucose during the ten seconds immediately preceding tone onset. The response to both CS and UCS during base trials was HR acceleration. The response to tone habituated in all groups, but the acceleration to glucose was maintained throughout conditioning. Although no conditioned response to the tone developed over trials, a large HR deceleration appeared during extinction to the absence of the UCS in the Conditioning Group only. This deceleration was interpreted as an orienting response to the absence of an expected event.     

A developmental comparison of the effectiveness of encoding tasks.

In Experiment 1, the free-recall performance of young children, college students, and older adults was examined. Subjects encoded words by simply learning them, by studying them in either base or elaborate sentence frames, or by constructing sentences. Overall recall was better for the college students than for the children or for the older adults, and the college students recalled best in the simple learning condition. The young children recalled best in the sentence construction condition; recall by older adults did not vary as a function of the encoding tasks. In Experiment 2, college students and older adults recalled a categorized list, encoding the words by simply learning them, by studying them in elaborate sentence frames, or by completing word fragments. For both age groups, simple learning produced the highest level of recall. These results suggest that organization provides the most effective encoding system and that older adults may need a more obvious basis for organization than do younger adults. Younger and older adults recalled equally well only when organization was discouraged by conceptual processing.     

A comparison of syntax in young stutterers and nonstutterers

This study compares the syntactic structure of the spontaneous speech of a small group of stutterers and nonstutterers, using a method of constituent analysis. Speech samples were taped during play sessions with subjects, and the tapes were then transcribed and analyzed according to preselected constituent criteria. The stutterers were in the early stages of stuttering and had been diagnosed as stutterers by experienced clinicians. The method of analysis proved to be highly reliable. Differences were found in the number of complete clauses, the number of complex sentences, and in clause types between the two groups.     

Mechanisms of developmental change in infant categorization

Computational models are tools for testing mechanistic theories of learning and development. Formal models allow us to instantiate theories of cognitive development in computer simulations. Model behavior can then be compared to real performance. Connectionist models, loosely based on neural information processing, have been successful in capturing a range of developmental phenomena, in particular on-line within-task category learning by young infants. Here we describe two new models. One demonstrates how age dependent changes in neural receptive field sizes can explain observed changes in on-line category learning between 3 and 10 months of age. The other aims to reconcile two conflicting views of infant categorization by focusing on the different task requirements of preferential looking and manual exploration studies. A dual-memory hypothesis posits that within-task category learning that drives looking time behaviors is based on a fast-learning memory system, whereas categorization based on background experience and assessed by paradigms requiring complex motor behavior relies on a second, slow-learning system. The models demonstrate how emphasizing the mechanistic causes of behaviors leads to discovery of deeper, more explanatory accounts of learning and development.     

A developmental comparison of the processing of two types of visual information

Simple geometric forms and spatial position markers were tachistoscopically presented to Ss from four age groups (ranging from five years to adult) who responded by recreating the visual array with magnetic tokens.The basic findings were: (a) Ss remembered item positions better than identities; (b) no asymptote of position recall was reached by any age group when up to five position markers were presented; (c) when required to process identity information, position memory suffered, younger Ss showing the greatest decrement; (d) with unlimited viewing time, the pattern of results relating identity and spatial recall was not altered; (e) recall was better for the locations of position markers than for locations of geometric items.The results supported an hypothesis of separate processing mechanisms for spatial location and identity information. Improvement with age seems to result from an increasing ability to integrate the functioning of these separate mechanisms.     

A comparison of the Probe technique and conventional therapy for young stutterers

This study contrasted the gains made in speech theraphy by 39 stutterers, 15 of whom were treated by conventional methods and 24 by the Probe technique. It was found that the Probe technique yielded substantially greater gains in fluency than did the conventional method, having more influence on final performance than factors such as initial fluency, time since onset of stuttering, or the presence of other unacceptable behaviors.     

Psychologists' evaluations of individual assessments: A comparison on the basis of graduate training and professional affiliation

Recent research on individual psychological assessments for personnel decision-making purposes has indicated a great deal of variability in practice. This study compared the responses of psychologists who evaluated the same set of assessment protocols on the basis of graduate training and professional affiliation. Results indicated few differences in evaluations of those assessed or in the way assessments were conducted. Concerns about training for and the practice of individual assessment are discussed.     

A cross-cultural comparison of the developmental items of five ethnic groups in the southwest

A population of 3,067 Mexican-American, Pueblo Indian, Navajo Indian, Black, and Anglo elementary children were administered the Draw-A-Person for norming and comparison against the existing Koppitz scoring procedure. A significant number of items for each of the five ethnic groups changed categories with final score interpretation affected. A significant difference in percentage of items drawn by the five ethnic groups was also found, as were regional differences on certain items.     

Clinical,developmental and social aspects of infant crying and colic

Persistent unexplained infant crying in the first few months is a common source of distress for parents and is costly for the health services. The aim was to assess the merits of developmental and social conceptualizations of this phenomenon, compared to the clinical approach as represented by the concept of colic. From a community sample of 530 infants, 67 who met the ‘rule of threes’ definition of colic by fussing and crying for 3 or more hours per day at 4-5 weeks of age were chosen. To avoid confusion, these infants were called ‘persistent criers’. Groups of ‘evening criers’ (N = 38) and ‘moderate cries’ (N = 55) were also selected. These 160 infants were assessed by researcher measures of their consolability and by maternal diary measures of their amounts of fussing, crying and colic behaviour when 5-6 weeks old. The persistent and evening criers cried more than the moderate criers. However, irritable, ‘fussy’ behaviour was the predominant form of distress for all three groups of infants. Colic bouts–defined as ‘bouts of intense, unsoothable crying and other behaviour, perhaps due to stomach or bowel pain’–were rare even among the persistent criers and only 7% of these infants were found to be inconsolable. The results support growing evidence that normal infant developmental processes are central to this phenomenon. In addition, social interactions between infants and parents, and parental subjective variables, appear to be involved. Colic was distinguished as a rare and separate form of distress by the infants' mothers. Further evidence needs to determine whether colic is a distinct clinical phenomenon or an extreme degree of normal distress interpreted within a western cultural framework.     

Perception of object unity in chicks: A comparison with the human infant

Newly hatched chicks (Gallus gallus) were imprinted on a display consisting of two rod pieces that moved above and below a central occluder. On test trials, the chicks approached a complete rod in preference to two rod pieces. This finding, supported by those from control coditions, suggests that chicks, soon after hatching, perceive object unity. The results are compared with those from human infants.     

Processing implications and presuppositions by schoolchildren and adults: A developmental cross-linguistic comparison

Findings from two experiments are reported in this study. The findings from Experiment I show that (a) processing implications on constructions with implicative verbs (Karttunen, 1970, 1971) in Greek, displaying equivalent properties to English, is an easy task for fourth-, fifth-, and sixth-graders and adults under no time restrictions, as other studies have shown; (b) processing presuppositions on implicative verbs is a difficult task even for adults, unlike Clark's (cf. particularly Clark & Clark, 1977) theory claims; (c) commissive verbs according to Austin's (1962) and Searle's (1969) analyses behave as implicative verbs, contradicting Karttunen's (1971) theory; (d) nonimplicative verbs elicit implicative meaning, unlike the predictions of Karttunen's (1970, 1971) theory. Experiment II corroborates the results from Experiment I using a non-European language (Lebanese-Arabic). The data from both experiments are discussed within the framework of Clark's theory on given-new information, pointing out its limitations to the comprehension system. Alternative explanations are suggested.     

Conjoint developmental trajectories of young adult alcohol and tobacco use

Developmental and etiological advances have set the stage for considering trajectories of problem behavior across the life course, but little work thus far addresses co-occurring problem behavior trajectories. Although recent work characterizes drinking and smoking trajectories, none has explored the course of concurrent drinking and smoking. Using panel data from the Monitoring the Future Project (N=32,087), the authors applied growth mixture modeling to 4 waves of heavy drinking and smoking in a young-adult sample. The authors extracted a single latent group membership factor from heavy drinking and smoking. Associations between trajectory classes and risk factors were relatively unique to the substance being predicted. The association of smoking with alcohol expectancies and delinquency appeared to exist by virtue of smoking's comorbidity with drinking.