For example, designers may make design decisions to ensure that critical tasks are performed by users with their preferred hand. Theoretically, this should help to speed-up performance and reduce errors. To show how confusing this can be when designing to accommodate users' performance and preferences, consider the results of the following study on hearing. In this study, all participants were right-handed. Some past studies of handedness found a higher incidence of right-handedness in females, and in older people.
Recent studies report no differences due to gender or age.
However, left-handers are more likely to exhibit a bilateral representation of speech.