What Is the Function of a Computer Mouse?

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There was a time when every computer was equipped with a mouse, but today many people prefer to use a touchpad or touchscreen for computer interaction. These newer technologies perform the same function as the mouse, which is to position a pointer on the display. An additional important function of a mouse is to allow you to execute a variety of commands via the mouse buttons and wheel.


Tracking Function of a Mouse

The mouse is a small device that fits into the palm of your hand. When you move the mouse on a flat surface, a pointer on the computer display moves in a corresponding direction. This pointer is often referred to as a mouse pointer. The mouse pointer may change its shape or size on the display when it enters specific regions of the screen. Older mouse technology used a tracking ball to measure the device's movement. Today, most mouse devices use a light sensor to measure movement, making them more precise and easier to use. Another advancement in mouse technology is that most mouse devices now connect to computers wirelessly, unlike older wired models.


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Mouse tracking uses relative positioning, which means that the surface where you move the mouse does not need to be the same size and shape as the monitor where the mouse pointer is displayed. Instead, the speed with which you move the mouse determines how far the pointer will travel. A slow drag moves the pointer a small distance while a quick drag moves it farther. This makes the mouse more ergonomic for the average user than an absolute tracking device like a touchscreen, where movement is mapped one-to-one on the display.

Other Uses of a Mouse

Besides moving the pointer, a mouse can be used to execute computer commands using mouse gestures. Common mouse gestures include point, click, right-click, double-click, drag, right-drag, rotate wheel and press wheel. Gestures are executed using the mouse wheel or the two buttons (referred to as right and left) that are included on most mouse devices.


When using a two-button mouse, gestures like single-click and double-click are executed with the left mouse button. Single-click is usually used to select an object, while double click opens an object. The right-click gesture is executed with the right mouse button and it typically pops up a contextual menu that displays options related to the current software context. For single-button mouse devices that are supported by Mac OS X, right mouse button gestures are accomplished by combining button and keyboard gestures. Mouse gestures can also be combined. For example, pressing the left button and dragging the mouse is used to select one or more lines of text in Microsoft Word.