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.

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.

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