Individual Differences In Growth Research Articles

INVESTIGATING THE EFFECT OF WIDE READING ON LISTENING COMPREHENSION OF WRITTEN LANGUAGE

Previous research on the relationship between wide reading and listening comprehension provided indirect evidence that wide reading may be impacting children's listening comprehension. In the present study we looked at growth in listening comprehension of 146 children from third grade to fifth grade and their fifth-grade estimate of accumulated wide reading as measured by an instrument using a checklist-with-foils logic, the Title Recognition Test. Employing hierarchical multiple regression, we isolated the relationship between wide reading and listening comprehension. The results indicated that individual differences in growth of listening comprehension from third grade to fifth grade were significantly related to wide reading. These findings imply that reading a lot may influence listening comprehension, thus adding support to the educational practice of providing time for children to read independently and encouraging more and varied reading outside of school.

Transition from a random to an ideal free to an ideal despotic distribution: the effect of individual difference in growth

Individual differences in growth can lead to a monopolistic form of food competition. We studied the long-term transition in the mode of competition and the distribution of individuals between food patches of the cloned salmonid fish, Oncorhynchus masou ishikawae, in the laboratory. This transition was accompanied by growth depensation, i.e., the increase over time in the variance of size between individuals resulting from the differences in individual growth rates. The 120-cm experimental tanks were divided into two compartments (patches) between which an opaque partition was placed. Fish were able to move freely between the patches and therefore were able to assess the patch quality using long-term memory, but they were not able to see the food input in the other patch directly. The distribution between the two food patches, the amount of food gained, and the growth and the agonistic behavior of four groups of six individuals were observed over 4 weeks. We found that (1) within-group variation in body weight increased with time; (2) on average, the better patch was used by more individuals than predicted by a random distribution but fewer individuals than predicted by an ideal free distribution, and (3) the distribution and pat- tern of resource use by the fish changed over the 4-week experimental period from a random distribution to an ideal free distribution and finally to an ideal despotic distribution. We suggest that growth depensation causes the long-term change in the spatial distribution and pattern of resource use by competitors.

Life history of the sandhopper Pseudorchestoidea brasiliensis (Amphipoda) in sandy beaches with contrasting morphodynamics

Exposed marine beaches are physically rigorous habitats in which macrofauna community patterns are related to physical factors such as sedimentary parameters and wave/swash processes. In this context, a consistent increase in species richness, abundance and biomass from reflective to dissipative conditions has been widely reported, and proposed as a paradigm of sandy beach ecology. Here, we examine this hypothesis on the demography and life history characteristics of the sandhopper Pseudorchestoidea brasiliensis of Uruguay. Abundance, population structure by sex and size, individual growth, natural mortality, fecundity, female maturity and size at maturity, and the length-weight relationship were compared between populations of 2 microtidal exposed sandy beaches that differed widely in physical characteristics (i.e. grain size; slope, penetrability and water content), during 20 consecutive months. Contrasting with the predictions of 'the sandy beach ecological paradigm, the population of P. brasiliensis at the reflective beach presented (1) higher abundance both for males and females; (2) higher egg production potential and recruitment levels; (3) lower natural mortality; and (4) no major differences in individual growth and estimated life span to those of the dissipative beach population. On the contrary, growth in weight, individual fecundity and average size at maturity were higher for the dissipative beach population. We conclude that population level responses to variation in sandy beach morphodynamics may markedly differ from community level responses, and thus macroscale, world-wide community patterns could not necessarily characterise life history and demographic variations of individual species in a similar manner. We suggest that the paradigm of the forces generating patterns in sandy beach communities has underestimated the importance of population regulation mechanisms in these communities.

Longitudinal studies of achievement growth using latent variable modeling

This article gives a pedagogical description of growth modeling of longitudinal data using latent variable methods. The growth modeling is described using an example of mathematics achievement developing over grades 7 to 10 in two cohorts of students. The article describes the basic idea behind growth modeling of individual differences in growth over time and applies it to mathematics achievement development as a function of background variables such as gender, mother's education, and home resources. The modeling ideas are described in words, diagrams, and formulas. The discussion covers modeling that assesses the form of the growth, the influence of background variables on the growth, multiple-cohort analysis, analysis with missing data, and multiple-group analysis of males and females. A corresponding set of analyses are performed on the mathematics data to illustrate the modeling ideas.

Differences in individual growth of newly settled 0-group plaice ( Pleuronectes Platessa L.) in the intertidal of neighbouring wadden sea areas

Growth of temporarily isolated subpopulations of tidally migrating 0-group plaice was registered during summer 1991 in two adjacent Wadden Sea areas separated by a high tidal watershed. One area had tidal sand flats with extremely poor food conditions for juvenile flatfish, as frequently occurring in the Wadden Sea. In contrast, the other area had mixed sediments which provide rich benthos conditions for the fish. By otolith microstructure analysis we demonstrated that individual fish grew faster in this rich area than in the other. Differences in growth between the two sites could be attributed to differences in food quality and quantity. Along the transect rich in benthos, individual growth equalled maximum growth calculated from a currently used, but not yet published, growth model for the early bottom-dwelling stages, which was thereby validated in the field.

Analyzing change in short-term longitudinal research using cohort-sequential designs.

This article illustrates a method for approximating longitudinal data analysis by combining information from different overlapping age groups to form a single developmental growth curve. Using this method, hypotheses about the form of growth, the extent of individual differences in growth, and factors that affect the rate and pattern of growth are investigated. The example used to illustrate this method examines the growth of externalizing behavior and of negativity in parent-child relationships during early adolescence using assessments from multiple methods and multiple informants. These 3 dimensions changed significantly during this period, with parental negativity increasing more rapidly after age 12. However, there were substantial individual differences in the pattern of change in these dimensions. Gender of child and type of family situation (nondivorced, divorced, and remarried) were investigated as possible factors affecting change.

Analyzing change in short-term longitudinal research using cohort-sequential designs.

This article illustrates a method for approximating longitudinal data analysis by combining information from different overlapping age groups to form a single developmental growth curve. Using this method, hypotheses about the form of growth, the extent of individual differences in growth, and factors that affect the rate and pattern of growth are investigated. The example used to illustrate this method examines the growth of externalizing behavior and of negativity in parent-child relationships during early adolescence using assessments from multiple methods and multiple informants. These 3 dimensions changed significantly during this period, with parental negativity increasing more rapidly after age 12. However, there were substantial individual differences in the pattern of change in these dimensions. Gender of child and type of family situation (nondivorced, divorced, and remarried) were investigated as possible factors affecting change.

Predicting growth in reading ability from children's exposure to print

Previous research on whether exposure to print could account for individual differences in growth in children's reading comprehension has produced conflicting results ( Anderson, Wilson, & Fielding, 1988; Taylor, Frye, & Maruyama, 1990). We conducted a longitudinal study of growth in reading ability employing two new indicators of print exposure that use a checklist-with-foils logic and that have very brief administration times. We found that individual differences in third- to fifth-grade growth in reading were significantly related to these indicators of print exposure. It appears that the extent to which individuals engage in literacy activities is a significant contributor to developed reading ability. Further studies of the cognitive consequences of literacy could be facilitated by the use of the easily administered indicators of print exposure that we examined in this study.

Individual differences in growth and access to food in the freshwater snail,Physa acuta

Individual differences in growth and access to food in the freshwater snail,Physa acuta

Individual growth variation of red-spotted masu salmon,Oncorhynchus masou rhodurus, in a mountain stream

Individual growth patterns in red-spotted masu salmon,Oncorhynchus masou rhodurus, were examined by mark and recapture in a mountain stream, central Japan. The growth pattern varied substantially among individuals of the same age cohort in the stream. Mean absolute growth rates of the individuals were neither significantly different between years, study sections along the stream course, or sexes, but showed significant differences between seasons. No correlation was found between the individual growth rate of fish and the area of pools they inhabited. However, there was considerable growth variation among inhabitants of the same pool. Within a pool, larger individuals grew more rapidly than smaller ones, despite there being no significant relationship between individual growth rates and initial body weights in the stream overall. Individual growth differences probably resulted from growth depensation caused by intraspecific competition within individual pools.

Comparison of energy budget among six teleosts—IV. Individual differences in growth and energy budget

1. 1. Energy budgets were determined for individuals of six teleost fishes fed ad libitum at 25°C. 2. 2. Pronounced intraspecific variabilities existed in the growth rate and most components of the energy budget in the six species. 3. 3. In two species, individual differences in growth were mainly caused by variations in the proportion of food energy allocated to metabolism; in one species, individual growth differences were mainly caused by variations in feeding rate; in the other three species, both variations in feeding rate and in the proportion of food energy allocated to metabolism were important in causing the growth differences.

Geographic variation in the growth rates of Littorina littorea and L. saxatilis

The two intertidal grazers Littorina littorea and L. saxatilis occupy extensively overlapping distributions on both sides of the Atlantic. Morphological, electrophoretic and physiological evidence suggests that the direct developer L. saxatilis is more geographically differentiated than the planktonic developer L. littorea. This hypothesis was tested by collecting both species in 1980 and 1981 from three geographically separated beaches in Massachusetts, USA, marking them, and releasing them in two of the sites. Individuals from all three L. littorea populations, grown at a common site, tended to grow at similar rates, while L. saxatilis exhibited consistent population differences in individual growth. This study supports the view that L. saxatilis achieves its broad geographic distribution via locally adapted ecotypes, while L. littorea achieves its distribution by individual physiological plasticity.

The Early Development of Precocity

The time is ripe for extending our interest in gifted children downward to infancy and preschool. Existing research is reviewed, and a plea made for extending work in the following areas: (1) identification and description, (2) prediction from early behavior to (similar or dissimilar) later attainments, (3) studies of the origins of commitment and high achievement motivation, (4) naturalistic and experimental studies of the nurturance of exceptional abilities. Gifted babies and toddlers are compelling both in their own right and for what they can tell us about the emergence of individual differences.

Statural development parallels IGF I levels in subjects of constitutionally variant stature.

Using a protein-binding assay which measures mainly IGF I, serum levels of insulin-like growth factor (IGF) were determined in 263 children and adolescents of constitutionally variant stature but with normal GH secretion following provocative stimuli. A positive correlation was found between height age and the logarithm of IGF levels (r = 0.67, P less than 0.001). Furthermore, a correlation was found in the tall and short subjects as a group between the ratio of IGF/normal IGF for age and between the ratio of growth rate/normal growth rate for age (r = 0.53, P less than 0.001). Subjects were compared at the same stage of development. At a given bone age or stage of puberty, tall subjects had significantly higher IGF levels than short subjects (P less than 0.005). After the completion of growth, IGF levels in both short and tall subjects stabilized within the normal range. Nevertheless, their mean levels remained significantly different (P less than 0.001). Our results suggest that in normal children and adolescents, differences in IGF I secretion may be at least partially responsible for the individual differences in growth.

A model for the dynamics of an annual plant population

A model for the dynamics of a single species population of plants is proposed and its use demonstrated by the analysis of a simple example. The model incorporates the effects of microsite variation by allowing for individual differences in growth and death rates within each season. We demonstrate that an increase in the variance in individual growth rates may increase both the chances that a plant population will persist and the equilibrium size of that population. We also show that even if size-dependent death is occurring, it may not have a significant effect on the shape of the size frequency distribution. An extension of the model to multispecies communities of plants suggests an experimental procedure to determine whether competition is responsible for excluding a particular plant species from a community that appears otherwise to be suitable. A more detailed analysis of the model for a two-species community produces conditions for competitive coexistence reminiscent of those from the Lotka-Volterra competition equations. Another extension suggests that selection will favor those genotypes that maximize the product of germination probability and mass of seeds produced, if survivorship and growth are not substantially altered. Finally, an analog to r- and K-selection theory for animal populations is developed. Selection in low-density populations favors increasing growth rate, and in high-density populations favors minimizing the effect of neighbors on one's own growth rate.

Understanding correlates of change by modeling individual differences in growth

The study of correlates of change is the investigation of systematic individual differences in growth. Our representation of systematic individual differences in growth is built up in two parts: (a) a model for individual growth and, (b) a model for the dependence of parameters in the individual growth models on individual characteristics. First, explicit representations of correlates of change are constructed for various models of individual growth. Second, for the special case of initial status as a correlate of change, properties of collections of growth curves provide new results on the relation between change and initial status. Third, the shortcomings of previous approaches to the assessment of correlates of change are demonstrated. In particular, correlations of residual change measures with exogenous individual characteristics are shown to be poor indicators of systematic individual differences in growth.

PATTERNS OF GROWTH IN HEIGHT AND WEIGHT FROM BIRTH TO EIGHTEEN YEARS OF AGE

In this report is displayed the range of variation observed in the growth curves of height and weight in a series of 134 children observed from birth to 18 years. For purposes of simplification the individuals have been classified on the basis of their rates of growth during three successive 6-year intervals. Even in terms of this crude classification several basic facts about individual growth patterns of height and weight are apparent. The wide range of differences between individuals applies not only to facts about size at specific ages but also to the pattern of change followed from age period to age period. The rate of growth during early childhood, i.e. before 6 years of age, is associated with, but not specifically predictive of, size at maturity and timing of the adolescent growth spurt. Individuals with rapid growth before 6 years of age tend to have large mature size and early adolescent growth spurt. It will be the objective of future reports from this research project to determine the manner in which the individual differences in growth demonstrated and classified here are related to aspects of physical development, to environmental influences such as dietary intake and to the level of health of the child.

Bayesian longitudinal multilevel item response modeling approach for studying individual growth differences

Bayesian longitudinal multilevel item response modeling approach for studying individual growth differences