Cognitive Dimensions


Who

T.R G. Green, Marian Petre, Alan Blackwell

What

“A broad-brush evaluation technique for interactive devices and for non-interactive notations. It sets out a small vocabulary of terms designed to capture the cognitively-relevant aspects of structure, and shows how they can be traded off against each other .” [2]

When

1989 - Present

Why

A method was needed that allowed designers without extensive cognitive science training to critically evaluate the usability of their designs (information artifacts) and discuss the tradeoffs that occur based on design decisions.

Cognitive Dimensions
Introduction & Purpose

Cognitive Dimensions, or more formally, the Cognitive Dimensions of Notations theory is a framework for evaluating the usability of information artifacts originally developed by T. R. G. Green in 1989. [1]

Marian Petre and Alan Blackwell are two additional HCI researchers who have helped to support the development and application of the Cognitive Dimensions framework.

Petre teamed up with T. R. G. Green in 1996 to further refine the Cognitive Dimensions Framework. [2]

Alan Blackwell has worked with T. R. G. Green to develop tutorials and questionnaires to help make Cognitive Dimensions more easily usable for HCI practitioners.[3]

Cognitive Dimensions continues to be used today by usability practitioners and designers (for example, a recent study utilized the Cognitive Dimensions Framework to evaluate constraint diagrams [4]).


Activity Theory


Activity theory is a conceptual framework originating from the socio-cultural tradition in Russian psychology. Since the early 1990s, Activity Theory has been applied in Human Computer Interaction (HCI) and evolved into one of the most noteworthy theories in the field. It focuses on the purposeful interaction between the "subject" and the "object".

"Activity," the foundational concept of activity theory, is understood as a relationship between the subject, (that is, an actor) and the object, (that is, an entity objectively existing in the world. A common way to represent Activity Theory is "S < - > O." [2]

Activity Theory
Contributions to HCI

In general, activity theory contributions to the field of HCI have been of the following three types:

1. Theoretical re-framing of some of the most basic HCI concepts. [2]

2. Providing conceptual tools for design and evaluation. [2]

3. Serving as a theoretical lens in empirical studies. [2]

There are two major versions of activity theory: the approach developed by Leoniev, and a closely relatied approach proposed by Engeström. By "activity theory” in general we mean an aggregated framework comprising a combination of these two approaches. [2]


Situated Action


Who

Lucy Suchman

What

Situated Action studies the relations between people and their circumstances to achieve intelligent action. While people may have plans of action in mind, their actual action may diverge depending on what is actually happening in a specific situation. [1]

When

1987 (Publication of Plans and Situated Action book)

Why

Represents an important, principled, and successful attack on classical cognitive-science based theories of human-computer interaction. The reconceptualization of role of plan in human-computer interaction widely influenced and field of Science and Technology Studies (STS), Computer-Supported Cooperative Work (CSCW), Artificial Intelligence, Cognitive Science, and HCI. [2]

Influences modern practices of ethnography-based usability testing and evaluation.

Situated Action
Introduction & Purpose

Situated Action traces it’s roots to Lucy Suchman’s Plans and Situated Action book. Influenced by cultural anthropology, Situated Action approach offers detailed, ethnographic accounts of how humans use technology differently in different contexts, illustrating how they can be different from the ideal plans conceived by the technology designer. [1]

As a theoretical lens, Situated Action describes and explains human-computer interactions, without attempting to predict user performance or prescribe guidance for design.