In psychology, affordance is what the environment offers the individual. In design, affordance has a narrower meaning; it refers to possible actions that an actor can readily perceive.
American psychologist James J. Gibson coined the term in his 1966 book, The Senses Considered as Perceptual Systems, and it occurs in many of his earlier essays. His best-known definition is from his 1979 book, The Ecological Approach to Visual Perception:
A writing process is a set of mental and physical steps that someone takes to create any type of text. Almost always, these activities require inscription equipment, either digital or physical: chisels, pencils, brushes, chalk, dyes, keyboards, touchscreens, etc.; each of these tools has unique affordances that influence writers' workflows. Writing processes are very individualized and task-specific; they frequently incorporate activities such as talking, drawing, reading, browsing, and other activities that are not typically associated with writing.
Perceptual psychology is a subfield of cognitive psychology that concerns the conscious and unconscious innate aspects of the human cognitive system: perception.
A pioneer of the field was James J. Gibson. One major study was that of affordances, i.e. the perceived utility of objects in, or features of, one's surroundings. According to Gibson, such features or objects were perceived as affordances and not as separate or distinct objects in themselves. This view was central to several other fields as software user interface and usability engineering, environmentalism in psychology, and ultimately to political economy where the perceptual view was used to explain the omission of key inputs or consequences of economic transactions, i.e. resources and wastes.
Social constructivism is a sociological theory of knowledge according to which human development is socially situated, and knowledge is constructed through interaction with others. Like social constructionism, social constructivism states that people work together to actively construct artifacts. But while social constructivism focuses on cognition, social constructionism focuses on the making of social reality.
A very simple example is an object like a cup. The object can be used for many things, but its shape does suggest some 'knowledge' about carrying liquids (see also Affordance). A more complex example is an online course—not only do the 'shapes' of the software tools indicate certain things about the way online courses should work, but the activities and texts produced within the group as a whole will help shape how each person behaves within that group. A person's cognitive development will also be influenced by the culture that they are involved in, such as the language, history, and social context. For a philosophical account of one possible social-constructionist ontology, see the 'Criticism' section of Representative realism.
Optical flow or optic flow is the pattern of apparent motion of objects, surfaces, and edges in a visual scene caused by the relative motion between an observer and a scene. Optical flow can also be defined as the distribution of apparent velocities of movement of brightness pattern in an image.
The concept of optical flow was introduced by the American psychologist James J. Gibson in the 1940s to describe the visual stimulus provided to animals moving through the world. Gibson stressed the importance of optic flow for affordance perception, the ability to discern possibilities for action within the environment. Followers of Gibson and his ecological approach to psychology have further demonstrated the role of the optical flow stimulus for the perception of movement by the observer in the world; perception of the shape, distance and movement of objects in the world; and the control of locomotion.