All had at least five hours of previous experience using a mouse, and even the experienced mouse users performed better in pointing tasks using the light pen, Charness said. In addition, people who were asked to use their nonpreferred hand to complete pointing and clicking tasks performed better with the light pen than the mouse. That finding suggests that those who no longer have use of their preferred hand because of disease or disability may find it easier to use a light pen, a pointing device that causes the cursor to appear instantly when placed in front of the computer screen. Touching the screen with the pen tip is the same as pressing a mouse button. Further, the relatively weak difference in performance between preferred and non-preferred hands gives us hope that if injury or disease impaired our preferred hand, we could adapt pretty quickly to using the other hand for computer tasks.
Light pens do have some drawbacks.
And Charness must do further study to determine the effectiveness of the light pen when people combine tasks, such as typing and pointing. The most unexpected result of the study was that people were not very good judges of what device would work best for them, Charness said. The finding that people were not good judges of what was best for them suggests that computer hardware and software designers cannot simply design a highly flexible interface with the expectation that people will customize it effectively. Designers should try to develop and offer configurations that are optimized for different types of users.