Most children make adorable slip-ups in grammar when they're learning to speak. Now scientists say the mistakes could vary by gender.
Boys and girls tend to use different parts of their brain to learn some fundamental parts of grammar, according to a new study.
"Sex has been virtually ignored in studies of the learning, representation, processing and neural bases of language," said lead author Michael Ullman, a neuroscientist at Georgetown University. "This study shows that differences between males and females may be an important factor in these cognitive processes."
For the study, published in Developmental Science, researchers investigated the different brain systems that children used when they made mistakes like "Yesterday I holded the bunny." They found that girls tended to use a process that dealt with memorizing words and associations between them, whereas boys used a process governing the rules of language.
Research has shown that women tend to be better at tasks that employ what is called declarative memory, such as memorizing word lists. They use what is called a "mental lexicon" to memorize and remember words. Procedural memory, controlled by a different part of the brain, is used to combine words in sentences--research has shown both genders may use this process equally well.
"Although the two sexes seem to be doing the same thing, and doing it equally well, they are using two different neurocognitive brain processes to do it," Ullman said.
Men and women may process words differently because of different levels of the hormone estrogen, which is much higher in females and affects brain processing, according to Ullman.
For this study, Ullman and his colleagues studied how a group of 10 boys and 15 girls, between the ages of two and five, used regular and irregular past-tense forms of verbs. Because irregular tenses like "held" are memorized in declarative memory, the researchers predicted that girls would be less likely to make mistakes like "holded", as those errors result from children applying the "add -ed" rule of regular verbs when they can't remember the form of the irregular verb.
But surprisingly, the results of the study showed the exact opposite to be the case: Girls used "holded" far more than boys. Digging deeper, the researchers found that words liked "holded" had many rhyming verbs with regular past-tense forms, like folded and molded.
According to the researchers, the girls were using their declarative memory to memorize the regular past tense forms and then applying those forms to rhyming irregular verbs.
"This memory is not just a rote list of words, but underlies common patterns between words, and can be used to generalize these patterns," Ullman said.
But for boys, there was no association between the number of rhyming regular past-tense verbs and the verbs that were used incorrectly. According to Ullman, this suggests that boys were using their procedural memory that contains the rule to add "-ed" to create past tense verbs.
Because these brain systems are used for more than just language, the study's findings suggest that "men and women may tend to process various skills differently from one another," Ullman said.
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