Interaction

Interaction is a kind of action that occurs as two or more objects have an effect upon one another. The idea of a two-way effect is essential in the concept of interaction, as opposed to a one-way causal effect. A closely related term is interconnectivity, which deals with the interactions of interactions within systems: combinations of many simple interactions can lead to surprising emergent phenomena. Interaction has different tailored meanings in various sciences. Changes can also involve interaction.

Casual examples of interaction outside science include:

Interaction (statistics)

In statistics, an interaction may arise when considering the relationship among three or more variables, and describes a situation in which the simultaneous influence of two variables on a third is not additive. Most commonly, interactions are considered in the context of regression analyses.

The presence of interactions can have important implications for the interpretation of statistical models. If two variables of interest interact, the relationship between each of the interacting variables and a third "dependent variable" depends on the value of the other interacting variable. In practice, this makes it more difficult to predict the consequences of changing the value of a variable, particularly if the variables it interacts with are hard to measure or difficult to control.

The notion of "interaction" is closely related to that of "moderation" that is common in social and health science research: the interaction between an explanatory variable and an environmental variable suggests that the effect of the explanatory variable has been moderated or modified by the environmental variable.

Face-to-face interaction

Face-to-face interaction (less often, face-to-face communication or face-to-face discourse) is a concept in sociology, linguistics, media and communication studies describing social interaction carried out without any mediating technology. Sociologist Erving Goffman in his classic 1959 book The Presentation of Self in Everyday Life defined face-to-face interaction as "the reciprocal influence of individuals upon one another's actions when in one another's immediate physical presence". Linguist Mary Ritchie Key defined research on face-to-face interaction as one "aimed at discovering, documenting and describing regularities in the actions observable in actual interactions."

The concept of face-to-face interaction has been of interest to scholars since at least the early 20th century. One of the earliest social science scholars to analyze this type of interaction was sociologist Georg Simmel, who in his 1908 book observed that sensory organs play an important role in interaction, discussing examples of human behavior such as an eye contact. His insights were soon developed by others, including Charles Cooley and George Herbert Mead. Their theories became known as symbolic interactionism. By the mid-20th century there was already a sizable scholarly literature on various aspects of face-to-face interaction. Works on this topic have been published by scholars such as Erving Goffman and Eliot Chapple.