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Human factors

See also: human-computer interaction, usability, user experience

Introductory articles

• Usability and human factors
  This presentation focuses on human factors issues, beginning with a discussion of the roots of usability in the field of human factors. Through a series of everyday examples it introduces the principles of feedback, visibility, affordances, constraints and natural mapping, as discussed in Donald Norman's The Design of Everyday Things. Norman's conceptual models and the gulfs of execution and evaluation are also illustrated through the use of examples. Finally, human factors issues relevant to the web are discussed.

Discussion articles

• A review of the cocktail party effect
  The "cocktail party effect''--the ability to focus one's listening attention on a single talker among a cacophony of conversations and background noise--has been recognised for some time. This specialised listening ability may be because of characteristics of the human speech production system, the auditory system, or high-level perceptual and language processing. This paper investigates the literature on what is known about the effect, from the original technical descriptions through current research in the areas of auditory streams and spatial display systems. The underlying goal of the paper is to analyse the components of this effect to uncover relevant attributes of the speech production and perception chain that could be exploited in future speech communication systems. The motivation is to build a system that can simultaneously present multiple streams of speech information such that a user can focus on one stream, yet easily shift attention to the others. A set of speech applications and user interfaces that take advantage of the ability to computationally simulate the cocktail party effect are also considered.

• Cognitive load and the rule of seven
  "How many is too many", as far as links and information bits on a page?

• Data presentation: tapping the power of visual perception
  Why do we quickly comprehend some forms of data presentation, and not others? The answer is vital to designers of decision-support applications. This installment of our series connects insight into the process of vision with presentation best practices.

• Decisions, decisions... what's a poor user (and designer) to do?
  Psychologists and economists who study how people make decisions describe two types of decisions: compensatory and non-compensatory.

• Perceptual factors in information visualisation
  Computer technology has now reached the stage where even a modest desktop computer can output vast and complex bodies of information. This information needs to be communicated to us appropriately if we are to make best use of it. This can be accomplished, in part, by producing information visualisations that best exploit the powerful human visual system. In order to do this, information visualisation products should utilise the knowledge gained from research into how human visual perception actually works.

• Reducing reliance on superstition
  How to improve design decisions by reducing reliance on superstition. Let’s start with Miller’s 'Magic 7'.

• The human interface
  The phrase 'human error' is taken to mean 'operator error', but more often than not the disaster is inherent in the design or installation of the human interface. Bad interfaces are slow or error prone to use. Bad interfaces cost money and cost lives. There are a large range of techniques which can be employed during the design of the human interface and, as in any discipline, part of the professional's skill is in knowing when it is appropriate and cost-effective to apply which technique. This article attempts to give you a taste of some of the issues surrounding the design of an effective human interface.
  (Alan Dix)

• The magical number seven, plus or minus two: some limits on our capacity for processing information
  The original version of the infamous article by George Miller on the limits of cognitive processing.

• The measurement and comparison of cross-device mental models
  "Do we have different mental models for the same application being used in different devices? Our findings imply that the answer is yes to this question. Does that mean that mental models are device-dependent? Our findings here are not explicit enough to be able to answer this question. But in the interview with Don Norman for this issue, he suggested that our mental models are context-dependent; i.e., we do not have a different mental model for the web site in each device, but rather we have a different mental model for the specific context of a given web site and a given device, and our interaction with that web site varies because of the device characteristics."
  (Avi Parush)

• The myth of "Seven, plus or minus 2"
  One guideline that needs closer attention is the "Magic Seven, Plus or Minus Two" (7±2) rule of thumb. This principle has often been applied to determine the number of items in a navigation menu on a web page. It arose to satisfy a tactical need to make quick design choices and to objectively justify navigation to site stakeholders.

• The worst interface ever
  Never, ever, ever let systems-level engineers do human interaction design unless they have displayed a proven secondary talent in that area.

• Three numbers that (should) have nothing to do with user interface design
  Some numbers are famous. For example, pi is known throughout the world. Other numbers are famous within particular subcultures. For fans of humorous novelist Douglas Adams, 42 is famous as the answer to life, the universe, and everything. Likewise, within the subculture of user interface designers, the most famous number is Miller's (1956) magical number 7±2. More than forty years after its initial publication, Miller's figure is cited in academic literature, at usability-related conferences, and more privately, in countless interface design meetings.

• Web page design: implications of memory, structure and scent for information retrieval
  Much is known about depth and breadth tradeoff issues in graphical user interface menu design. We describe an experiment to see if large breadth and decreased depth is preferable, both subjectively and via performance data, while attempting to design for optimal scent throughout different structures of a website. A study is reported which modified previous procedures for investigating depth/breadth tradeoffs in content design for the web. Results showed that, while increased depth did harm search performance on the web, a medium condition of depth and breadth outperformed the broadest, shallow web structure overall.

Research articles

• The science of word recognition
  "Given that all the reading research psychologists I know support some version of the parallel letter recognition model of reading, how is it that all the typographers I know say that we read by matching whole word shapes? It appears to be a grand misunderstanding. The paper by Bouma that is most frequently cited does not support a word shape model of reading."
  (Kevin Larson)

• What sounds do people love and hate?
  Sounds have an impact on user behaviour. But what sounds do people love and hate? We wanted to find out, so we ran a large-scale exploratory study (over 700 participants, over 15,000 sound evaluations).