People in today's modern workplace spend a large percentage of their day working on a device intentionally designed to slow them down. The original keyboard was designed so people could not type fast enough to jam mechanical typewriter mechanisms. This keyboard layout has remained to this day with no significant modification. Scientifically designed keyboards (like Dvorak) have failed to catch on for various reasons. The QWERTY (or Shoales) keyboard layout seems here to stay; but, that does not mean that it cannot be improved upon. Improvements analyzed in this experiment are backspace key movement and split keyboard.
With ergonomic keyboard's popularity increasing, Several manufacturers tout long term benefits. This study will attempt to justify using ergonomic keyboards by demonstrating increased production.
Modification of a backspace key, for thumb activation, allows for left hand fingers to remain at home position (A-S-D-F) when backspacing. Due to a thumb being a stronger and more durable digit than the pinky, it is believed it could support the increased typing responsibility. This study will investigate more efficient use of a thumb by allowing one thumb to operate a backspace key.
Split keyboard modification is intended to provide a more comfortable typing position. It is believed that a more relaxed hand posture will increase the performance and subjective satisfaction with a keyboard.
Most keyboard studies fall into two general categories: different input or different layout. The different input keyboard studies compare different ways of entering data. These different input methods include touchscreen (Sears, 1991) and Stylus and Soft Keyboard (Soukoreff and MacKenize, 1995). Other studies have analyzed effects of completely different keyboard layouts. These studies compare an ABCDE and/or Dvorak keyboards to traditional QWERTY keyboards (Dvorak, 1936), (Navy, 1944), as quoted by (Liebowitz and Margolis, 1990). No studies were found that analyzed effects of a partial keyboard reconfiguration as proposed in this study. The keyboards studied are commercially availiable from well established large corporations.
Fitt's law, a psycological model of human movement, has been used as performance model for human computer interaction (MacKenzie, 1991). It is only natural to extend this to a common human computer interaction (keyboard entry). Combining this law and key activation frequency distribution, a theoretical upper and lower bounds on typing speed can be determined for a particular keyboard configuration (Soukoreff and MacKenize, 1995).
Fitts law can be written as (known as the Shannon formulation)
MT = a + b log2(A/W + 1). (1)
Where MT is the time to move to and select a target of width W which lies at distance A. Where a and b are constants determined through linear regression.
The movement of a backspace key to the left side of the space bar should reduce MT of backspace activation. The term A/W will be reduced to near zero because distance traveled for key activation will be reduced and key width is increased. An arguement could be made that decreasing spacebar width will increase MT of spacebar activation; however, the right thumb (responsible for spacebar activity) has no other responsibilities and usually rests on or very near the spacebar . Therefore, key activation distance, A, is nearly zero and no increase in MT is expected.
The split keyboard studied has enlarged function keys, backspace key and space bar. Key activation distances are identical to standard keyboard for each hand. In other words, each hands characters have the same distance values. Accordingly there is no expected increase in the A/W term for the standard characters. Key width increasing for enlarged keys should serve to decrease the A/W value; therefore, overall MT should be slightly reduced. One thing should be mentioned is that single handed typing would require a much greater key activation distance; therefore, MT would increase significantly.
Norman and Rummelhart (1983) argue that for optimal typing speeds, a keyboard should be designed so that:
Proposed backspace key movement equalizes left and right hand loads. In modern computer environments, right hands are overloaded. They are responsible for return key activation, backspace key activation, and controlling directional arrows. Shifting backspace key activation to the left hand will equalize hand loading (especially for poor typists, who frequently use the backspace key).
The left thumb is not currently utilized in modern typing practice; therefore, giving it a function will minimize the frequency of same finger typing. The right pinky (currently responsible for the backspace key) is responsible for many keys whose use are on the rise. Computer directory structures (common on the internet) frequently use "/" or "\" keys and the "Return" key is often used to activate buttons. Removing responsibilities from the right pinky and designating a finger that currently has no responsibility will minimize same finger tying frequency.