"Yesterday I holded the bunny."

These slip-ups in grammar make little children adorable when they're learning to speak. But a new study has proved that these errors are gender linked. "Sex has been virtually ignored in studies of the learning, representation, processing and neural bases of language," said 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."

The researchers discovered that girls tended to use declarative memory (which stores words and associations between them, like word lists, using a "mental lexicon" to memorize and remember words), whereas boys used a logical process governing the rules of language.

Procedural memory, controlled by a different part of the brain, combines words in sentences and both genders may use it 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".

A group of 10 boys and 15 girls, aged two to five, were tested how they dealt with the use of regular and irregular past-tense forms of verbs. Because irregular tenses like "held" are memorized in declarative memory, the researchers supposed that girls would make less mistakes like "holded", as they are due to the application of the " -ed" rule of regular verbs.

The results were exactly the opposite: Girls used "holded" far more than boys. In fact, words liked "holded" had many rhyming verbs with regular past-tense forms, like "folded" and "molded".

The girls were using their declarative memory to stick the regular past tense forms and then applied them 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.

For boys, there was no association between the number of rhyming regular past-tense verbs and the verbs that were used incorrectly: they were using their procedural memory that contained the rule: add "-ed" to form the Past Tense of verbs. As these cognitive systems have more uses than just language, "men and women may tend to process various skills differently from one another," Ullman said.

Previous studies made on adults have already shown that, when learning a new language, males perform faster on catching grammar rules, while women were better at storing vocabulary and idiomatic expressions.