This study investigated intellectual development in 4-7 years old Greek and Chinese children. They were examined on speeded performance, working memory, reasoning, and self-awareness tasks in order to investigate possible effects of learning the Chinese logographic system on possible differences in intellectual development between these ethnic…

Ninety-six children from a high-iodine Chinese village were found to have higher goiter incidence, thyroid gland volume, and urinary/creatinine ratio than 51 children from an iodine-normal village. All children from both villages were euthyroid. Excess iodine did not substantially affect the children's physical or intellectual growth. (Author/JDD)