child development

Older news items (pre-2010) brought over from the old website

Math theory explains children's cognitive development

Around age five, children begin to understand that if John is taller than Mary, and Mary is taller than Sue, then John is also taller than Sue – Transitive Inference. They also begin to understand that there are more fruit than apples in a grocery store – Class Inclusion. Now a mathematical theory explains why these two reasoning skills appear at the same time. It seems that both involve the ability to apply two lines of thinking about a problem at the same time, whereas younger children are limited to one. The theory provides a good account not only of Transitive Inference and Class Inclusion, but also five other forms of inference that are acquired around the same age: Matrix Completion, Cardinality, Card Sorting, Balance Scale, and Theory of Mind.

Phillips, S., Wilson, W. H., & Halford, G. S. (2009). What Do Transitive Inference and Class Inclusion Have in Common? Categorical (Co)Products and Cognitive Development. PLoS Comput Biol, 5(12), e1000599. doi: 10.1371/journal.pcbi.1000599. Full text available at http://dx.plos.org/10.1371/journal.pcbi.1000599

http://www.eurekalert.org/pub_releases/2009-12/plos-omr120709.php

Genes more important for IQ as children get older

Data from six studies carried out in the US, the UK, Australia and the Netherlands, involving a total of 11,000 pairs of twins, has revealed that genes become more important for intelligence as we get older. The researchers calculated that genes accounted for some 41% of the variation in intelligence in 9 year olds, rising to 55% in 12 year olds, and 66% in 17 year olds. It was suggested that as they get older, children get better at controlling (or perhaps are allowed to have more control over) their environment, which they do in a way that accentuates their ‘natural’ abilities — bright children feed their abilities; less bright children choose activities and friends that are less challenging.

Haworth, C.M.A. et al. 2009. R Plomin The heritability of general cognitive ability increases linearly from childhood to young adulthood. Molecular Psychiatry, advance online publication 2 June 2009; doi: 10.1038/mp.2009.55

http://www.newscientist.com/article/mg20327174.600-genes-drive-iq-more-as-kids-get-older.html

Brain's organization switches as children become adults

Imaging studies of the brain while it is supposedly doing nothing have identified four brain networks with varying responsibilities. The networks typically involve tight links between several brain regions that are physically distant from each other. A new study involving 210 subjects aged 7 to 31 has now found that in contrast to the adult brain, most of the tightest connections in a child's brain are between brain regions that are physically close to each other. As the child grows to adulthood, the brain switches from an organization based on local networks based on physical proximity to long-distance networks based on functionality.

Fair, D.A. et al. 2009. Functional Brain Networks Develop from a “Local to Distributed” Organization. PLoS Computational Biology, 5(5), e1000381. Full text available at http://www.ploscompbiol.org/article/info%3Adoi%2F10.1371%2Fjournal.pcbi.1000381

http://www.physorg.com/news161605421.html
http://www.physorg.com/news160920910.html
http://www.livescience.com/health/090518-child-brain.html

Maturity brings richer memories

New research suggests adults can remember more contextual details than children, and that this is related to the development of the prefrontal cortex. While in a MRI scanner, 49 volunteers aged eight to 24 were shown pictures of 250 common scenes and told they would be tested on their memory of these scenes. In both children and adults, correct recognition of a scene was associated with higher activation in several areas of the prefrontal cortex and the medial temporal lobe when they were studying the pictures. However, the older the volunteers, the more frequently their correct answers were enriched with contextual detail. These more detailed memories correlated with more intense activation in a specific region of the PFC. A number of studies have suggested that the PFC develops later than other brain regions.

The report appeared in the August 5 advance online edition of Nature Neuroscience.

http://www.physorg.com/news105549812.html
http://www.eurekalert.org/pub_releases/2007-08/miot-msm080107.php

A first glimpse at healthy brain and behavioral development

Initial data from the National Institutes of Health (NIH) MRI Study of Normal Brain Development, a large, population-based study that began in 1999 and is documenting structural brain development and behavior from birth to young adulthood, has revealed that:

• Norms were higher with only healthy children being considered (the study excluded children who had any signs or known risk of serious neurological or psychiatric disorders).
• Gender differences were less evident. Boys performed better on perceptual analysis, and girls performed better on processing speed and motor dexterity. The slight advantage girls showed in verbal learning disappeared by adolescence. There was no difference in math ability.
• Income predicted IQ and academic achievement, but lower-income children performed better than in previous studies, with the study being restricted to healthy children.
• Performance climbed steeply from age 6, but leveled off overall for most tests between 10 and 12 years of age, then improved more slowly or not at all during adolescence.

For more information see http://www.brain-child.org/.

Waber, D.P. et al. 2007. The NIH MRI Study of Normal Brain Development: Performance of a Population Based Sample of Healthy Children Aged 6 to 18 Years on a Neuropsychological Battery. Journal of the International Neuropsychological Society, 13, 1-18.

http://www.eurekalert.org/pub_releases/2007-05/chb-afg051607.php
http://www.eurekalert.org/pub_releases/2007-05/nion-nst051507.php
http://www.physorg.com/news98692796.html
http://sciam.com/article.cfm?articleID=A15FAD05-E7F2-99DF-34B5A1856E790722&chanID=sa003

Kids can remember events even if they can't remember times

How do we remember when an event has occurred? Most of the time we do it by reconstructing the event and inferring the time from details stored. Given that, it should perhaps be no surprise to learn that while children aged 4 through 13 can recall the details of an event fairly well, they are unable to extrapolate further and link those details with a specific time of year, even when it occurs around a major holiday. The finding has implications for legal testimony, where lawyers are inclined to cast doubt on memories if the child is unable to recall when the event occurred.

Friedman, W.J. & Lyon, T.D.2005. Development of Temporal-Reconstructive Abilities. Child Development, 76(6), 1202

http://www.eurekalert.org/pub_releases/2005-11/sfri-kcr110805.php

Development of working memory with age

An imaging study of 20 healthy 8- to 30-year-olds has shed new light on the development of working memory. The study found that pre-adolescent children relied most heavily on the prefrontal and parietal regions of the brain during the working memory task; adolescents used those regions plus the anterior cingulate; and in adults, a third area of the brain, the medial temporal lobe, was brought in to support the functions of the other areas. Adults performed best. The results support the view that a person's ability to have voluntary control over behavior improves with age because with development, additional brain processes are used.

http://www.eurekalert.org/pub_releases/2004-10/uopm-dow102104.php

Reese, E. & Brown N. 2000. Reminiscing and recounting in the preschool years. Applied Cognitive Psychology, 14, 1-17.

Finding: Parents can help their child remember events that have happened to them by reminiscing with them (recalling with them events that they have shared) and encouraging them to recall details about unshared events.

Talk about past events can be classified as either reminiscing (discussingshared experiences) or recounting (discussing unshared experiences).
This study looked at reminiscing and recounting between preschoolers and their mothers. Forty children between three and five participated in the experiment. It was found that children reported more unique memory information when they were discussing unshared experiences (recounting) rather than shared. Mothers who provided morememory information during reminiscing and asked for more information during recounting had children who reported more unique information about events.

Buckner, J.P. & Fivush, R. 1998. Gender and self in children's autobiographical narratives. Applied Cognitive Psychology, 12, 407-29.

Finding: Gender differences in conversational style seem to appear at an early age. At age 8, girls' recounting of personal experiences are already more detailed and socially contexted than boys' narratives are.

This study looked at the differences between girls and boys in recounting personal experiences. The children were aged eight, and from a middle-class background. As has tended to be found with adults, it was found that the girls' narratives were longer, more coherent and more detailed than were the boys' narratives. The girls' narratives also tended to mention more people and more emotions, and to be placed in a social context.