Karine Mazens

Conceptual change in physics: children's naive representations of sound

Abstract The organization of physics knowledge (degree of coherence and nature of conceptual change) was studied in 89 6–10-year-old children using the concept of sound. We attempted to determine whether children apply properties of objects to sound or if they consider sounds as a vibratory process. Three properties of physical objects were studied: substantiality, weight, and permanence. The younger children considered sound more like an object than the older children did. Substantiality was attributed to sound more often than were weight and permanence. Based on the substantiality data, four mental models were identified (sound cannot pass through other objects unless there are holes, sound can pass through solids if it is harder than they are, sound is immaterial, sound is a vibratory process). We concluded that conceptual change in knowledge about sound does not happen through the sudden transfer of the concept from the ontological category of matter to the ontological category of processes, but rather through a slow and gradual process of belief revision, in the course of which the various properties of matter are abandoned in a hierarchical order.

Development of children’s ability to detect kinship through facial resemblance

Facial features appear to be a prominent kinship cue for ascribing relatedness among human individuals. Although there is evidence that adults can detect kinship in unrelated and unfamiliar individual’s faces, it remains to be seen whether people already possess the ability when they are young. To further understand the development of this skill, we explored children’s ability to detect parent-offspring resemblance in unrelated and unfamiliar faces. To this end, we tested approximately 140 children, aged 5–11, in two photo-matching tasks. We used a procedure that asked them to match one neonate’s face to one of three adults’ faces (Task 1), or to match one adult’s face to one of three neonate’s faces (Task 2). Our findings reveal asymmetrical performance, depending on the tasks assigned (performance of Task 2 is stronger than for Task 1), and on the sex of individuals who made up the parent-offspring pair (male parents are better matched with neonates than female parents, and boys are better matched than girls). The picture that emerges from our study is, on one hand, that the ability to detect kinship is already present at the age of five but continues to improve as one gets older, and on the other, that perception of parent-offspring facial resemblance varies according to the appraisers’ characteristics.

Children’s Approximate Number System in Haptic Modality

The approximate number system (ANS) is a primitive system used to estimate quantities. It can process quantities in visual and auditory modalities. The aim of the present study was to examine whether ANS can process quantities presented haptically. Moreover, to assess age-related changes, two groups of children (5- and 7-year-olds) were compared. In a newly designed haptic task, children compared two arrays of dots by touching them simultaneously using both hands, without seeing them, and for limited duration to prevent counting. Using Panamath, a frequently used visual ANS task, we verified that our population exhibited the typical pattern of approximation with visual arrays: Older children outperformed younger children, and an increased ratio between the two quantities to be compared led to more accurate responses. Performance in the haptic task revealed that children, in both age-groups, were able to haptically compare two quantities above chance level, with improved performance in older compared with younger children. Moreover, our results revealed a ratio effect, a well-known signature of the ANS. These findings suggest that haptic numerical discrimination in children is dictated by the ANS, and that ANS acuity measured with a haptic task improves with age, as commonly observed with the visual task.

What predicts mathematics achievement? Developmental change in 5- and 7-year-old children

Many changes occur in general and specific cognitive abilities in children between 5 and 7 years of age, the period coinciding with entrance into formal schooling. The current study focused on the relative contributions of approximate number system (ANS) acuity, mapping precision between numeral symbols and their corresponding magnitude (mapping precision) and working memory (WM) capacity to mathematics achievement in 5- and 7-year-olds. Childrens performance was examined in different tasks: nonsymbolic number comparison, number line estimation, working memory, mathematics achievement, and vocabulary. This latter task was used to determine whether predictors were general or specific to mathematics achievement. The results showed that ANS acuity was a significant specific predictor of mathematics achievement only in 5-year-olds, mapping precision was a significant specific predictor at the two ages, and WM was a significant general predictor only in 7-year-olds. These findings suggest that a general cognitive ability, especially WM, becomes a stronger predictor of mathematics achievement after entrance into formal schooling, whereas ANS acuity, a specific cognitive ability, loses predictive power. Moreover, mediation analyses showed that mapping precision was a partial mediator of the relation between ANS acuity and mathematics achievement in 5-year-olds but not in 7-year-olds. Conversely, in 7-year-olds but not in 5-year-olds, WM fully mediated the relation between ANS acuity and mathematics achievement. These results showed that between 5 and 7 years of age, the period of transition into formal mathematical learning, important changes occurred in the relative weights of different predictors of mathematics achievement.

Children's consideration of relevant and non-relevant facial features in kinship detection

The aim of this study was to clarify the understanding of biological inheritance in children (ages 5, 7, 9 and 11) and adults by using a new methodological approach. In a perceptual task, participants were asked to match the photo of a newborns face with the one of his/her mothers face, shown along with two other non-kin female faces. The non-kin female faces were either neutral, since they had no perceptual similarity to the newborns face (control condition), or shared with the target newborns face a salient perceptual facial feature irrelevant to kin detection, e.g., head orientation, open/closed eyes or mouth (experimental condition). Results showed that children could efficiently detect the mothers face by the age of 9 (control condition). Difficulties ignoring irrelevant salient perceptual properties occurred up to age 9 (experimental condition). We discussed whether these results could correspond to progressive conceptual changes in the understanding of inheritance.