CG007 Advanced HumanComputer Interaction Effective interaction II

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CG007 Advanced Human-Computer InteractionEffecti
ve interaction II

• Cognitive explanations of human error
• Activity theory

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Effective interaction II
Cognitive explanations of human error
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Models of users should acknowledge people make
errors

• Errors are part of normal human behaviour
• People make errors frequently
• Sometimes trivial
• Sometimes serious.
• You have to take this into account in design.
• If you design something assuming the user wont
  make errors then your model of the user is wrong
• Inevitable consequence is failure.
• But errors are bound up problem solving and with
  learning
• So not only is it good to design things so that
  errors are less likely
• It is also important to allow people to
  experiment, to play safely.

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Cognitive model of error - Mistakes, slips (or
lapses)
I have an objective in carrying out an activity,
but due to some action on my part I dont get
the intended result
Error
Arise from experiential cognition I wasnt
concentrating on the action, I dont usually need
to. (Implies skilled performance is involved)
Arise from reflective cognition I reflected on
the problem, but I made a wrong decision.
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Mistake or slip?

• Laura is editing some data on a spreadsheet.
• In the middle of doing one of the changes she has
  to call up another database to find some
  information.
• She wonders if she can copy several fields at
  once from the database and then paste them into
  the spreadsheet.
• She decides that this plan will work. When she
  pastes the cells into the spreadsheet all the new
  data is crowded into one cell and not distributed
  across several cells as you had expected.

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Mistake or slip?

• Julie is writing her report.
• She reads through the 3000 word text and finds
  nothing wrong with the phrase the results of
  our tests were not as we had excepted.

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Effective interaction II
Activity theory
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Activity theory an inclusive theory?

• offer the possibility of integrating the micro
  and macro concerns of those trying to improve
  our understanding of how to support work with
  technology.
• micro - the detailed minute-by-minute
  interaction between a user and a product (or
  system)
• macro - the wider social interaction with the
  product,
• The research problems which can be attacked more
  successfully with the use of the conceptual tools
  of Activity Theory, include the role of
  contextual factors in human computer interaction,
  the nature of cognitive artifacts, advantages and
  limitations of affordances, and user interface
  transparency, among others. (Bannon, 1997)
• Activity theory is optimistic about the
  potential for human development. (Nardi, 1998)
  does this explain why it hasnt found wider
  acceptance?.

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Some Activity theory concepts

• Activity refers to human activity only.
• Consciousness is social.
• Peoples activities are always directed to an
  outcome.
• People always use tools in their activities
  (tools might have a physical form might be mental
  constructs).
• Tools shape the way people interact with the
  world.
• Tools have both an enabling and constraining
  function.
• All human activity takes place in a social and
  cultural context.
• All tools carry the history of their development
  in their design.
• You are what you do.
• If you design mediating tools for others (such as
  computer hardware or software), you are also
  responsible, in part, for the consciousness of
  others

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Some Activity theory concepts

• Differentiation between internal and external
  activities
• internal activities cannot be understood if they
  are analysed separately, in isolation from
  external activities, because there are mutual
  transformations between.
• Internalisation - transformation of external
  activities into internal ones
• Externalisation
• it is the constant transformation between
  external and internal that is the very basis of
  human cognition and activity. (Nardi, 1998).

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Some Activity theory concepts

• Hierarchical scheme that describes the structure
  of an activity.
• Activity
• Action
• Operation
• Activities are motivated by human desires
• Actions can be operationalised, that is turned
  into operations.
• Operations can be conceptualized (Bodker, 1991)
  which means we think about what we are doing.
• Breakdown situations
• experienced as tensions, problems or
  contradictions in how we understand the
  situation.
• This is the central dynamic of activity theory
  and, according to Nardi (1998), distinguishes it
  from superficially similar approaches such as
  distributed cognition. 

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