MSc Physiotherapy, Faculty of Health Sciences, University of the Witwatersrand, 2009. / As the medical world advances, there is an ever increasing survival rate of children that are born prematurely and of a low birth weight. For this reason more and more research is being done to investigate the consequences of being born pre-term and underweight. Research has shown that children who are born prematurely may show signs of developmental delay later on in life (Johnson, 2007). Motor development has been shown to be more affected by prematurity than any other causative factor of prematurity (Goyen and Lui, 2002). The main aim of the study was to establish the differences in global development between pre-term and full-term infants at eighteen months. The Bayley Scales of Infant Development II (BSID II) were used to determine performance in both the pre-term and the full-term group. These results were statistically analysed in greater detail in the mental and the motor section. The Mental and Psychomotor Developmental Indices (MDI and PDI) of the BSID II were used to determine the extent of the mental and motor delays in this sample. The Household Economic and Social Status Index (HESSI) was used in order to ascertain if the socioeconomic status of a family had any bearing on the development of the child in both the mental and the motor categories. This was statistically analysed. The socio-economic factors assessed in this study did not show any statistical significance but did confirm that these children come from similar backgrounds. The results of this study showed that there is a delay in the pre-term group when compared with the full-term group. The mean MDI for the full-term group was 105.25, this is compared with the pre-term group of 81.9, which is statistically significant (p<0.001). The PDI for the full-term group showed a mean score of 109.6. The mean score for the pre-term group was 86.8. This also showed a statistical significance (p<0.001). The pre-term infants in this study showed a significant delay both in the mental and the motor domains. The cognitive delays may be linked to an under-developed corpus callosum due to the premature birth. The motor delays may be caused due to a decreased motor control and developmental dyspraxia. Infants that are born prematurely are at a higher risk to suffer from developmental delays in the cognitive, language and the motor developmental domains. This study confirms what has been found in previous studies showing cognitive development to be the developmental domain most affected by prematurity. The results of this study are important as they support policy change to ensure that these children are followed-up to allow the at-risk children to reach their full potential.

Thesis (Ph.D.)--Boston University. / This thesis examined the relationship between thinking dominated by perception and thinking guided by logic. It was suggested by Piaget's theory of cognitive development which defines modes of thinking in terms of logical forms as models of operation of the mind. Thus thinking unfolds in several stages, each characterized by a precursor of logic. Within this theoretical framework, the present study focussed on the supremacy of misleading perception at the onset of the concrete operational stage. The relationship was examined in a situation of incompatibility between perception and logic [TRUNCATED]

Recent research suggests that by 4 months of age infants are able to individuate objects using form features, such as shape and size, but surface features, such as pattern and color, are not used until later in the first year (Wilcox, 1999). The current study sought to investigate two possible explanations for this developmental hierarchy. The visual maturation hypothesis suggests that the order in which infants use features to individuate objects corresponds to the order in which they are most readily processed by the developing visual system. A second hypothesis, the information processing biases hypothesis, suggests that infants are biased to attend to form features because form features provide information that is relevant to reasoning about object interactions. One way to test these hypotheses is to investigate infants' ability to individuate objects based on luminance. Luminance is detected at birth, so, according to the visual maturation hypothesis, luminance, like shape and size, will be used to individuate objects early in the first year. However, luminance is a surface property, so according to the information processing biases hypothesis, luminance, like pattern and color, will be used to individuate objects late in the first year. In the current study, 7-month-old (Experiment 1) and 11-month-old (Experiment 2) infants' use of luminance information in an object individuation task was investigated. The narrow-screen event-monitoring paradigm developed by Wilcox and Baillargeon (1998a) was used. Infants saw an event in which a ball moved behind a screen and a second ball emerged from behind the opposite edge of the screen. In one condition, the balls were identical, suggesting the presence of one object (same-luminance condition), and in another condition, the balls differed in luminance, suggesting the presence of two objects (different-luminance condition). The screen was either too narrow (narrow-screen event) or sufficiently wide (wide-screen event) to occlude two objects simultaneously. Seven-month-olds looked equally at each event, whereas 11.5-month-old's looked longer at the narrow-screen event in the different-luminance condition. These results suggest that 11.5-month-olds, but not 7.5-month-olds used luminance information to conclude that two distinct objects were involved in the event, thus supporting the information processing biases hypothesis.

Number words or numerals are built using a compositional system, wherein a small number of words can be combined in multiple ways to represent many different numbers. Children not only have to learn the rules for combining numerals, but must also map certain combinations to specific arithmetic functions. One such combination involves a class of words called multipliers that are used in a multiplicative structure (e.g. “two hundred” maps to “two times one hundred”). How and when do children learn this mapping? There have been two contrasting theories of acquisition: (1) That the compositional rules themselves provide all the necessary tools in order to create the mapping (Hurford, 1975) or (2) the rules are learned by rote and children only make the mapping via explicit instruction and experience with real world objects (Fuson, 1990). To test these theories, 99 children between 4.5 and 6.5 years old were trained on a novel numeral phrase that either did (Experiment 1) or did not (Experiment 2) use a multiplier structure. With all other stimuli remaining the same, more children (43% vs. 10%) were able to determine the novel word was a multiplier when in the correct structure. Other possible avenues for learning this mapping, including being taught the place value system (Experiment 3) and experience counting (Experiment 4), did not fully explain why children did better with the correct syntax. Although the results of these experiments cannot entirely discount the theory put forth by Fuson, they do support Hurford’s theory that it is the rules themselves which allow children to map meaning onto complex numerals.

Recent research suggests that by 4 months of age infants are able to individuate objects using form features, such as shape and size, but surface features, such as pattern and color, are not used until later in the first year (Wilcox, 1999). The current study sought to investigate two possible explanations for this developmental hierarchy. The visual maturation hypothesis suggests that the order in which infants use features to individuate objects corresponds to the order in which they are most readily processed by the developing visual system. A second hypothesis, the information processing biases hypothesis, suggests that infants are biased to attend to form features because form features provide information that is relevant to reasoning about object interactions. One way to test these hypotheses is to investigate infants' ability to individuate objects based on luminance. Luminance is detected at birth, so, according to the visual maturation hypothesis, luminance, like shape and size, will be used to individuate objects early in the first year. However, luminance is a surface property, so according to the information processing biases hypothesis, luminance, like pattern and color, will be used to individuate objects late in the first year. In the current study, 7-month-old (Experiment 1) and 11-month-old (Experiment 2) infants' use of luminance information in an object individuation task was investigated. The narrow-screen event-monitoring paradigm developed by Wilcox and Baillargeon (1998a) was used. Infants saw an event in which a ball moved behind a screen and a second ball emerged from behind the opposite edge of the screen. In one condition, the balls were identical, suggesting the presence of one object (same-luminance condition), and in another condition, the balls differed in luminance, suggesting the presence of two objects (different-luminance condition). The screen was either too narrow (narrow-screen event) or sufficiently wide (wide-screen event) to occlude two objects simultaneously. Seven-month-olds looked equally at each event, whereas 11.5-month-old's looked longer at the narrow-screen event in the different-luminance condition. These results suggest that 11.5-month-olds, but not 7.5-month-olds used luminance information to conclude that two distinct objects were involved in the event, thus supporting the information processing biases hypothesis.

Number words or numerals are built using a compositional system, wherein a small number of words can be combined in multiple ways to represent many different numbers. Children not only have to learn the rules for combining numerals, but must also map certain combinations to specific arithmetic functions. One such combination involves a class of words called multipliers that are used in a multiplicative structure (e.g. “two hundred” maps to “two times one hundred”). How and when do children learn this mapping? There have been two contrasting theories of acquisition: (1) That the compositional rules themselves provide all the necessary tools in order to create the mapping (Hurford, 1975) or (2) the rules are learned by rote and children only make the mapping via explicit instruction and experience with real world objects (Fuson, 1990). To test these theories, 99 children between 4.5 and 6.5 years old were trained on a novel numeral phrase that either did (Experiment 1) or did not (Experiment 2) use a multiplier structure. With all other stimuli remaining the same, more children (43% vs. 10%) were able to determine the novel word was a multiplier when in the correct structure. Other possible avenues for learning this mapping, including being taught the place value system (Experiment 3) and experience counting (Experiment 4), did not fully explain why children did better with the correct syntax. Although the results of these experiments cannot entirely discount the theory put forth by Fuson, they do support Hurford’s theory that it is the rules themselves which allow children to map meaning onto complex numerals.

Based on classic and contemporary theories of cognitive development by Vygotsky, Luria, and Zelazo and colleagues, the main objective of the present study was to systematically evaluate the association between different aspects of language, namely semantic and syntactic knowledge, and specific executive functioning (EF) abilities (working memory, inhibition, and flexibility) in preschoolers. Sixty-seven children age 3-5 years were administered a battery of EF and language measures. A latent variable approach was used to estimate performance on EF tasks. A two-factor model consisting of working memory/inhibition (WM/INH) and flexibility provided the best fit for the data. The results showed that syntactic ability uniquely explained a significant amount of variance in both WM/INH and flexibility over and above age and semantic ability. Furthermore, children’s complex syntax scores predicted their performance on complex blocks of flexibility tasks. These findings provide preliminary evidence for the association between children’s understanding of the structure of language and EF. / Graduate / 0620 / eyeung@uvic.ca

国立情報学研究所で電子化したコンテンツを使用している。 / 国立情報学研究所で電子化したコンテンツを使用している。

国立情報学研究所で電子化したコンテンツを使用している。

Previous examinations of young children's political cognition have mainly followed a socialization framework, through large-scale surveys of children's developing comprehension of the adult political world as a knowledge-goal. However, this research was formulated in the belief that children's political understanding develops as a consequence of their attempts to comprehend the political realities present in their own social environment. Therefore, as the school represents an important micropolitical context in children's lives, this study investigated their understanding of the system of the school. The empirical work reported in this thesis first presents a broad picture of the developmental trends in children's understanding as they attempt to make sense of the school, with their perceptions of such political concepts as power, authority, rules, roles and decision-making exhibiting differences with age. However, further empirical studies, examining the children's thinking for wider influences, suggested that the children's perceptions of the social environment are subject to a very complex pattern of influences, which are not necessarily the consequences of either age or cognitive differences. There was evidence of contextual effects on children's differentiation of school rules and of links between the children's attitudes and the attitudes of both teachers and parents. More importantly, there were indications that the children's perceptions of school were also subject to influences associated with their social categories, such as socio-economic class, gender and birth order. Given the extent and significance of these influences on the children's thinking which were revealed in this research, it is argued that the development of social cognition in children is much too complex for an interpretation based solely on changing cognitive capacities. It is therefore concluded that this study presents compelling evidence in favour of a social representations perspective on the developmental trends in children's political thinking.