Index cards stacked

Stacked index cards, a classic organizational tool, studied for their influence on library cataloging and the development of filing systems.

About this subject

Index cards are rectangular pieces of cardstock traditionally used to record information in a standardized format. They emerged in 18th-century Europe but gained widespread popularity in the 19th century with the expansion of public libraries. Librarian Melvil Dewey, creator of the Dewey Decimal System, was among the first to adopt standardized 3x5 inch cards, a size that became nearly universal. The versatility of index cards led to their adoption in offices, archives, and even research laboratories, such as those of anthropologist Claude Lévi-Strauss, who used them to organize ethnographic data.

In Brazil, index cards were widely used in school and university libraries until the digitization of catalogs. The technique of 'fichamento' (summarizing and referencing information on cards) is still taught in scientific methodology courses. Interestingly, the design of index cards inspired the interface of digital note-taking apps like Evernote and Notion, which maintain the metaphor of organizable 'cards'.

A lesser-known aspect is the use of index cards in artificial memory systems, such as the 'Memex' conceived by Vannevar Bush in 1945, which envisioned a mechanical device for storing and retrieving microfilmed cards. Today, physical index cards are still used in specific contexts, for example, in cognitive psychology tests to evaluate short-term memory or in board games like 'Dixit', where picture cards replace textual ones.

Frequently Asked Questions

What is the standard size of an index card?

The most common size is 3 x 5 inches (7.6 x 12.7 cm), standardized by Melvil Dewey in the 19th century.

Are index cards still used today?

Yes, though less common in libraries, they are still used in field research, board games, and psychology tests.

Who invented index cards?

There is no single inventor, but librarian Melvil Dewey popularized the standardized format in the late 19th century.