Offer character (also request character , offer , or affordance , from the English: affordance ) is the property offered by an object - obviously present or actually given - for subjects (humans or animals). For people, a chair has the character of being suitable for sitting or climbing up (not for an elephant). A switch has the character of an offer that it can be flipped into the other position - on the other hand, being petted is not part of its character.
There are limits to the nature of the offerings of the objects, which result from physical, physical, logical or cultural reasons. Examples of this:
- A three-ton hammer could not be used by a human to drive nails (physically).
- A mouse pointer cannot be moved beyond the edge of the screen (physically).
- In the case of a switch strip with a left and a right switch for controlling two devices next to each other, the left switch should operate the device on the left and the right switch the device on the right (logical).
- A red light means “stop!” (Cultural).
The English usability term Affordance , which was created by Donald Norman as a transfer of an ecological approach of perception by James J. Gibson (1904–1979) to designed artefacts, cannot be easily translated into German. The Germanized expression “affordance” is often not understood. It is therefore mostly recommended to use the expressions “invitation character” or more precisely “offer character”; the English term is now often used in practice.
Affordance in the interface design
Affordance is per se a desirable feature in the development of user-friendly user interfaces because it supports intuitive operation of the system . For example, a drop shadow or 3D effect supports the meaning of a button that it can be pressed. This approach of implementing real interactions in technical user interfaces is also called skeuomorphism . A counter-current to this is the currently more popular flat design , which, as its name gives it , is rather consistently “flat” and “minimalist”. There the affordance is no longer given by the similarity to the real interaction elements, since it is assumed that buttons , for example, are now recognized as such even without a 3D design.
Affordance in archeology and other cultural studies
In the archaeological context, the term describes the "possible use (s) specified by the physical properties of an object" and is therefore closely linked to considerations of functionality. Depending on the material, condition, surface and, above all, the shape of an object, the possible uses of an artifact are seen relative to its user and the specific usage situation, which is why independent material, visual and written sources should be included in the scientific interpretation if possible to be able to reconstruct the original context of use. The affordance theory therefore plays an important role in addition to the actor-network theory in the discussion about the theoretical conception of materiality triggered by the material turn , for example for the theoretical foundations of the Collaborative Research Center 933 “Material Text Cultures” at the Ruprecht-Karls-Universität Heidelberg .
With regard to the latter in particular, there has recently been an attempt to make the concept of affordance fruitful for the interpretation of media use, for example in media sociology. However, especially with regard to digital media that communicate via digital artifacts, it can be stated that these often do not have a clear prompting character. While it is hardly possible to eat with a shovel, a computer is a non-specific machine that can be used, for example, for bookkeeping as well as for games, the generation of knowledge, for the pursuit of private obsessions and for community projects. The affordance character here lies at most in an encouragement to contingent (deviating, varying) use. On the other hand, cloud offers such as chat services have a very inviting character, for example to report regularly with new posts or photos.
- James Jerome Gibson: The senses considered as perceptual systems . Houghton Mifflin, Boston 1966. Dt .: The senses and the process of perception . Huber, Bern 1973. ISBN 3-456-30586-9 .
- James Jerome Gibson: The ecological approach to visual perception. Houghton Mifflin, Boston 1979. Dt .: Perception and Environment . Urban & Schwarzenberg, Munich 1982. ISBN 3-541-09931-3
- Harold S. Jenkins: Gibson's “Affordances”: Evolution of a Pivotal Concept. Journal of Scientific Psychology, December 2008, (p. 34–45)
- Donald Norman: The Design of Everyday Things. Basic Books, New York 2013
- Reed, E./ Jones, R. (Eds.) (1982): Reasons for Realism. Selected Essays by James J. Gibson . Lawrence Erlbaum, Hillsdale. ISBN 0-89859-207-0
- Richard Fox, Diamantis Panagiotopoulos, Christina Tsouparopoulou, Affordanz. In: Michael R. Ott, Rebecca Sauer, Thomas Meier (eds.): Materiale Textkulturen. Concepts - materials - practices (= material text cultures 1). Berlin / Boston / Munich 2015. ( open access ). ISBN 978-3-11-037129-1
- JJ Gibson, The Senses and the Process of Perception (1973), p. 346
- Richard Fox, Diamantis Panagiotopoulos, Christina Tsouparopoulou, Affordanz. In: Michael R. Ott, Rebecca Sauer, Thomas Meier (eds.): Materiale Textkulturen. Concepts - materials - practices (= material text cultures 1). Berlin / Boston / Munich 2015, p. 66
- Richard Fox, Diamantis Panagiotopoulos, Christina Tsouparopoulou, Affordanz. In: Michael R. Ott, Rebecca Sauer, Thomas Meier (eds.): Materiale Textkulturen. Concepts - materials - practices (= material text cultures 1). Berlin / Boston / Munich 2015, p. 67
- Nicole Zillien: The (re) discovery of the Media - The Affordanzkonzept in media sociology. Sociologia Internationalis 46 (December 2008), issue 2, pp. 161-181.