Sunday, January 29, 2006

Cross-cultural study compares cognitive development in 3-to-5-year-olds

Sabbagh, M.A., Xu, F., Carlson, S.M., Moses, L.J., Lee, K. (2006). The development of executive functioning and theory of mind. Psychological Science, 17, 1, 74-81.

I find this article extremely interesting for many reasons. The researchers decided to compare a group of Chinese preschoolers to American preschoolers. They administered tests of verbal abilities to match controls and then they administered several tests of executive functioning.

There was a compelling rationale for conducting this study - culturally, it was noted that Chinese children were required to display inhibition of impulse control at earlier ages than their American counterpart. Genetically, it appears that the dreaded 7-repeat-allele of the dopamine receptor gene (which is associated with ADHD) is quite rare in China (1.9% of the population) especially when compared to populations in the US (48.3%). And, as we all know children with ADHD show difficulties inhibiting their impulsivity. (Much of this prior research is discussed in several chapters of D'Amato, Fletcher-Janzen and Reynolds's text School Neuropsychology .

This, in of itself, is a fascinating concept - that the combined pressure of cultural standards (via child-rearing practices) eliminates much of the "lack of inhibition" in the general population, while biology serves to ensure that extreme cases of "inhibition lack" are not commonly experienced.

The authors found that:

  • "executive functioning" (the ability to control our attention and behavior) develops more rapidly in Chinese preschoolers than in North Americans. Associated with the frontal lobe of the brain, executive functioning skills allow us to focus on goals even when there are distractions.
  • When tested for the development of another, related ability called "theory of mind" (understanding that people's actions are motivated by thoughts and feelings), however, Chinese pre-schoolers did not appear to performance any better than those in North America. Previous research had shown that within cultures, advances in executive functioning were associated with advances in theory of mind development. However, Dr. Sabbagh's findings show that advances in executive functioning are not themselves sufficient to demonstrate theory of mind understanding.
  • In the study more than 100 Chinese and North American three-to-five-year-olds were tested on a set of eight executive functioning and five theory of mind tasks. On every one of the executive functioning tasks, the Chinese children scored higher. Most of the executive functioning tasks were inhibition-esque, like the Stroop color-naming task.
  • But not a single theory of mind task showed the same cultural difference. This is odd, since the presence of increased executive functioning appears to predict the presence of theory of mind.
  • However the authors offer as a possible explanation that the development of theory of mind is perhaps moderated by social experienced. They remind us that previous research has shown that children with siblings tend to have better theory of mind conceptualization; Chinese children often do not have this luxury due to the "1 child per family" legal restriction.

Despite these issues, genetic contributions and child rearing practices of Chinese parents appear to go a long way to helping develop theory of mind, although social experiences with peers perhaps may be a necessary ingredient to the pot.

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