production than the males and this finding was not due to mothers speaking more with daughters than sons. In addition, boys between 2 and 6 years as a group did not show higher performance in language development over their girl counterparts on experimental assessments. In studies using adult populations, 18 and over, it seems that the female advantage may be task dependent. Depending on the task provided, a female advantage may or may not be present. Similarly, one study found that out of the 5.5% of American children with language impairments, 7.2% are male, and 3.8% are female. There are many different suggested explanations for this gender gap in language impairment prevalence. Lateralization effect on language It is currently believed that in regards to brain lateralization males are left-lateralized, while females are bilateralized. Studies on patients with unilateral lesions have provided evidence that females are in fact more bilateralized with their verbal abilities. It seems that when a female has experienced a lesion to the left hemisphere, she is better able to compensate for this damage than a male can. If a male has a lesion in the left hemisphere, his verbal abilities are greatly impaired in comparison to a control male of the same age without that damage. However, these results may also be task-dependent as well as time-dependent. Fine motor development rate Shriberg, Tomblin, and McSweeny (1999) suggest that the fine motor skills necessary for correct speech may develop more slowly in males. This could explain why some of the language impairments in young males seems to spontaneously improve over time. Over-diagnosis It is also suggested that the gender gap in language impairment prevalence could also be explained by the clinical over diagnosis of males. Males tend to be clinically over diagnosed with a variety of disorders. Visibility The study by Shriber et al. (1999) further explains that this gap in the prevalence of language impairment could be because males tend to be more visible. These researchers reveal that male children tend to act out behaviorally when they have any sort of disorder, while female children tend to turn inward and develop emotional disorders as well. Thus, the high ratio of males with language impairments may be connected with the fact that males are more visible, and thus more often diagnosed. Writing development Research in writing development has been limited in psychology. In the research that has been