Human Computer Interaction:

Mick McQuaid




  • Q and A from last time
  • Cognition
  • Readings
  • Break (may happen later depending on time)
  • Discussion leading (Asma Sifaoul)
  • Design Critique (Christina Jia)
  • Article Presentation (Sree Teja Kalakota)
  • Figma tutorial (Vaishnavi Dwivedi)

Q and A from last time


  • gestalt principles and human perception
  • model human processor
  • gestalt principles
  • human visual system
  • Gestalt principles, how vulnerable and unreliable the human mind can be but also how it predicts details based on unconscious instincts and habits
  • I think Model Human Processor (MHP) is the most important point I learned today. We could use that many time on our career.

More on Learning

  • I think the most interesting, but not shocking, item of information was that Ronald Reagan cut funding for research in human factors. I wonder what research is still happening in the military.
  • I found the relation between human cognition and visual perception to be very interesting. Especially the example of the human eyes looking at the person putting money in the jar. I think its important to study these things and how they relate to digital product design.
  • Visual perception is a major factor that affects the usability and understanding of a design. Use it as a tool.

Still more on learning

  • Design is not something that can be straightforward applied/taught. It’s helpful to know psychological principles but a lot of standards are up to fashion/taste/stakeholders
  • Learning about the Gestalt principles. I enjoyed the examples presented.
  • Using Framer!
  • I found the ‘Big Brother’ Eyes experiment fascinating, and wonder in the role it can play to promote honesty-based systems.

Even more on learning

  • Human capabilities and perception are complex variables HCI professionals must consider in designing products/services

Group impacts

How do font sizes, colors and contrast impact people from different groups?

This is an open question and depends on fads, fashions, how you define groups, and more.

Color theory

Before color accurate displays were invented, how was color theory and perception of digital interfaces studied? Or is this a relatively new area of HCI research which came to the surface even more so after significant advances in display technologies

Color theory is pretty old and exists as a science separate from HCI. There have been two different approaches to color theory in the present century, a psychological approach and a physiological approach. As for its age, I know that Newton explored it over 300 years ago.

Framer; Guest speakers

How do we plan to use framer in class? I’d be curious to hear other perspectives, will we have guest speakers?

Framer can be used in two ways in this course: to make a website and to make prototypes.

I don’t plan on any guest speakers but will entertain suggestions.


We talked a bit about cognitive psychology last week, particularly about Tversky and Kahneman’s work. This week we continue with some historical information.

Human cognition and emotion, from Norman (2013) pp 49–55

Levels of emotional design

Visceral level

basic, similar in all people, recoil from hot stove; input is immediate present, output is an affective state; not emotions but precursors to emotions; dismissed by people who don’t believe they are influenced by it;

Behavioral level

learned skills, subconscious response to patterns; overall awareness but no conscious awareness of details, e.g., speaking, sports; conscious of goals while behavioral level handles details; actions are associated with expectations as well as outcomes and lead to affect, both before and after;

Reflective level

conscious cognition, deep understanding, reasoning, slow, guilt, pride, blame, admiration; design takes place at all three levels: high-level cognition can trigger low-level emotion just as low-level emotion can trigger high-level cognition;

Levels of human processing

More on levels of human processing

Another way to think of these levels is illustrated in the previous frame: hardwired or prewired, short-term, and abstract or contemplative. All three levels play a role in our reactions to our environment, including designed artifacts.

Model human processor

Baby bubblehead, aka model human processor

A model human processor schema from wikipedia

Keystroke level model

Keystroke level model includes

  • operators, such as key presses, mouse pointing, choosing
  • encoding, lists of operators and operands for calculating time
  • heuristics, rules to apply to cognitive operators (e.g., choosing)

Keystroke model limitations

  • error
  • learning
  • functionality
  • recall
  • concentration
  • fatigue
  • acceptability


GOMS stands for

  • Goals
  • Operators (elementary actions)
  • Methods (groups of operators)
  • Selection rules (to choose methods)

protocol & verbal analysis

protocol analysis \(\rightarrow\) think-aloud process

Protocol analysis was an early hci tool

Verbal analysis differs in goals from protocol analysis

verbal analysis \(\rightarrow\) knowledge representation

Both analyses lead to maps

protocol analysis \(\rightarrow\) process map

verbal analysis \(\rightarrow\) knowledge map

Hick’s Law

Hick’s law predicts the time it will take for a user to make a choice, given the number of choices.

Hick’s law can be expressed as

\[t = b \log_2 (n + 1)\]

Fitts’s Law

Fitts’s law was actually discovered by Paul Fitts in the 1950s, but has been applied to the use of mice and other pointing devices as well as screen layouts since. It is perhaps the most widely invoked theory in the world of human computer interaction, and is depicted in the next frame.

Fitts’s law formulation

\[t = a + b \log_2\left(\frac{D}{W} + 1\right)\]


Readings last week include Johnson (2020): Ch 1–5

Readings this week include Johnson (2020): Ch 7–9, Norman (2013): Ch 2, 4

Let’s look at the Johnson book together, then the Norman book.


Milestone 0: Topic Idea

Can one person from each group report on theirs?


Chi, Michelene T. H. 1997. “Quantifying Qualitative Analyses of Verbal Data: A Practical Guide.” The Journal of the Learning Sciences 6 (3): 271–315.
Ericsson, K. Anders, and Herbert A. Simon. 1984. Protocol Analysis: Verbal Reports as Data. Cambridge, MA: MIT Press.
Johnson, Jeff. 2020. Designing with the Mind in Mind, 3rd Edition. Cambridge, MA: Morgan Kaufman.
Norman, Donald A. 2005. Emotional Design: Why We Love (or Hate) Everyday Things. Basic Books.
———. 2013. The Design of Everyday Things, 2nd Edition. Basic Books.



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