A pointing problem
By the early 1960s, computers could display text and simple graphics on screens, but there was no comfortable way to select items. Light pens, which a user pointed at a cathode ray tube, could be tiring to hold up to a vertical screen. Joysticks were designed for steering, not precise placement. Researchers at the Stanford Research Institute, in Menlo Park, California, were looking for a better answer as part of work on augmenting human thinking with computers.
The people involved
The usual credit goes to Douglas Engelbart, who led a group at the institute, with engineer William English building the early hardware. Engelbart’s research received funding from US government agencies including ARPA and NASA. English later carried out comparative testing. Other team members also contributed to the design, and as with many inventions the credit is better shared than given to one man.
Engelbart is often said to have sketched the idea in 1961 and to have developed it further by 1963. Dates in popular summaries vary by a year or two, and the precise sequence of sketches, models and demonstrations is not known in full detail. What is well documented is the patent that followed, discussed below.
What the first prototype looked like
The early device was a small wooden shell, roughly a block, holding two metal wheels mounted at right angles to each other. As the shell was pushed across a desk, one wheel rolled when the device moved forward or back, and the other when it moved sideways. Each wheel was connected to a potentiometer, a variable resistor, which sent a voltage that the computer converted into horizontal and vertical positions. A single red button sat on top. A cord trailing from the back to the computer looked, to the team, something like a tail, and that is the usual explanation for the name “mouse”. Even so, no one has a definitive record of who coined the word.
Later versions added more buttons, and the group experimented with a three-button design that became a common reference for their work.
Testing against alternatives
In the mid-1960s the group tested several pointing devices, including light pens, a joystick, a tablet and a device operated by the knee. People used each to select targets on a screen, and the researchers compared speed and errors. The mouse performed well in those comparisons, and it was also appealing because it could be used comfortably for long periods while a hand rested on the desk. The group chose it for their experimental system and refined it over the next years.
Not the only precedent
The mouse had precursors. In the early 1950s, a Canadian naval project known as DATAR used a trackball, a ball that is rolled by hand to move a marker, which is sometimes described as a trackball built from a bowling ball. This was a different device, since a trackball stays in place while the mouse moves, but it shared the idea of an input that controlled a cursor. Ralph Benjamin, a British engineer, also designed a roller ball for a Royal Navy system in the 1940s, though that account is less widely known. Because several lines of work existed, claims about the first of the early pointing devices need to be read carefully.
The patent
Engelbart and English filed a patent application for the “X-Y position indicator for a display system” in 1967, and it was granted in 1970. The text describes a hand-held block with wheels, the form of the wooden prototype. The patent was held by the institute, and the inventor reportedly did not earn large royalties from it. Any figures about licensing payments are best treated with caution.
Public debut
The mouse was shown to a large audience on December 9, 1968, at a computer conference in San Francisco, in a presentation later nicknamed the “Mother of All Demos.” For the prototype itself, the key point is that the wooden device was part of a larger system, not a stand-alone product.
Afterward
Several members of the group moved on to Xerox PARC in the early 1970s, where mice were used with the experimental Alto computer. Mice later became a regular part of personal computing, replacing the early wooden design with plastic cases and eventually optical sensors. Original prototypes and replicas are held in museum collections, and photographs of the wooden shell remain among the best-known images in computing history.
What can be said with confidence
The wooden mouse built at SRI was a well-documented step in pointing technology, and Engelbart and English are widely credited. The claim that it was “the first” pointing device is not accurate, since trackballs and light pens existed first, but it is the ancestor of the device now called a mouse.