Path Dependence - Other Examples

Other Examples

• A general type of path dependence is a typological vestige.
  • In typography, for example, some customs persist, although the reason for their existence no longer applies; for example the placement of the period inside a quotation in U.S. spelling. In metal type, pieces of terminal punctuation such as the comma and period are comparatively small and delicate (as they must be x-height for proper kerning.) Placing the full-height quotation mark on the outside protected the smaller cast metal sort from damage if the word needed to be moved around within or between lines. This would be done even if the period did not belong to the text being quoted.
• Evolution is considered by some to be path-dependent: mutations occurring in the past have had long-term effects on current life forms, some of which may no longer be adaptive to current conditions. For instance, there is a controversy about whether the panda's thumb is a leftover trait or not.
• In the computer and software markets, legacy systems indicate path dependence: customers' needs in the present market often include the ability to read data or run programs from past generations of products. Thus, for instance, a customer may need not merely the best available word processor but rather the best available word processor that can read Microsoft Word files. Such limitations in compatibility contribute to lock-in, and more subtly, to design compromises for independently developed products if they attempt to be compatible. Also see embrace, extend and extinguish.
• The QWERTY keyboard retains its layout from the design of early typewriters despite arguments that other layouts may be more efficient or ergonomic.