Wednesday, May 2, 2018

The advantages of fMRI in understanding child development

Talking with--Not Just to--Kids Powers How They Learn Language

In “Talking With-Not Just to-Kids Powers How They Learn Language”, Claudia Wallis from the Scientific American explores the anatomical mechanisms of language development in children, and how a divide in learning development exists across different socioeconomic strata in our society. Wallis cites a 1995 finding by Betty Hart and Todd Risley to explain that, by age four, children raised in poverty have heard 30 million fewer words than their wealthier peers. This gap in language development has been found to be a predictor for weaker academic performance among children from lower socioeconomic backgrounds. Wallis qualifies this finding with the fact that it is not just the sheer number of words, but also the act of having back-and-forth conversations (often called conversational turns or contingent talk among researchers) with children that improves their language skills.
Wallis cites a paper recently published in Psychological Science, in which researcher John Gabrieli employed fMRI (functional Magnetic Resonance Imaging) to find the anatomical bases of language development in 36 children aged four to six. The study found that parents from higher socioeconomic backgrounds engaged in more verbal exchanges with their children, and this translated to higher verbal ability scores when compared to children from lower-income families. fMRI scans showed that the Broca’s Area (associated with language and speech production) was more active when children with higher verbal ability scores listened to short recordings of stories. Wallis explains that these findings are important because we are living in an era where both children and adults are spending less time using face-to-face communication and more time with their devices. Wallis qualifies this concern by citing a 2017 finding by K. Hirsh-Pasek, in which it is established that when a cell-phone call interrupts a parent-child teaching interaction, the child’s learning is lost.
The studies Wallis cites substantially mirror Elizabeth Wakefield’s lecture on the importance of self-generated actions in novel verb-learning tasks in children. She discusses how fMRI technology has been employed to find that children who are given the opportunity to actively explore objects while learning novel verbs have improved connectivity in their sensorimotor systems, allowing for more concrete learning (James & Swain, 2010). The researchers found that the sensory and motor systems significantly interact during perception, and therefore greater activation of a child’s motor system improves their ability to learn action-verbs. This is due to the fact that the motor system experiences greater BOLD (Blood-oxygenation level-dependent) signaling when a child imagines physically manipulating an object in order to recall the action-verb they previously performed.

As we can see, both researchers employed fMRI technology to find that allowing children to perform self-generated actions improved their neuronal connectivity and learning development. Wakefield explored the importance of the sensorimotor pathway in helping children learn novel action words through active engagement with objects. Similarly, Gabrieli’s study examined the function of the Broca’s Area in children’s language development. It can be seen that encouraging children to physically or verbally engage rather than demonstrating these actions or words improves their overall learning development. The fMRI scans performed for both Wakefield and Gabrieli’s research have demonstrated this finding in separate brain networks. While Wakefield’s research found that the motor system is activated when children imagine previously performing certain actions, Gabrieli found that the Broca’s Area is activated when children imagine verbally responding to the words they are hearing. This shows that active engagement during working memory tasks and long-term memory encoding is important in multiple facets of a child’s cognitive development. These findings can even be translated to the learning process in adults, showing that learning by doing is more effective than learning by listening.


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