Week 6 — Hand-Eye Coordination and Time Requirements

New things

New things I discovered this week and that I had never realized:

This week concludes my psychology lectures. The last chapters of Designing with the Mind in Mind is all about time. Specifically the time it takes for our human mind and cognition to perceive objects and events. When we think back into our past or ponder upon our future. Or the time it takes for us to learn from events and act on our plans. It is all a matter of time. We also took a more in depth look at how knowledge of our response time delays can help us design better interactive systems.

Source: Red Cheeks Factory

What I learned

This is what I learned about this week:

  • Fitts’ law is “a predictive model of human movement” used in human–computer interaction (HCI) and ergonomics. The law predicts that the time required to rapidly move to a target area is a function of the ration between the distance to the target and the width of the target.
Source: Sketchplanations

Design implications of Fitts’ Law

  • Make click-targets big enough
  • Make the actual click-target at least as large as the visible click-target
  • Checkboxes should accept clicks on their labels as well as on the buttons
  • Leave plenty of space between buttons and links
  • Place important targets near the edge of the screen
  • Display choices in pop-up and pie menus menus if possible
  • For smartphone apps, consider using menus that people can reach easily with their thumbs
  • Steering law is another HCI and ergonomics model used to predict human movement and concerns itself with the time required to navigate or steer through a 2-dimensional tunnel.
Source: Nielson Norman Group

A tunnel can be imagined like this the playback scrubber at the bottom of a Youtube video. The white transparent area is a 2D “tunnel” whereby users “steer” their pointer or cursor and drag it through. “The steering time depends on the length and the width of the tunnel: the longer and the narrower the tunnel, the more time will be required to successfully steer through it.

Source: Youtube via Nielson Norman Group

Design implications of Steering Law

UI controls that require the user to keep the pointer in a narrow path while moving it will be slow and error-prone to use. Don’t require users to move a pointer within a narrow path toward a target.

Source: Freepik

In order to optimize graphical user interface designs, laws such as Fitts’ Law and Steering Law should not be overlooked by designers. The response time of the system does influences a user’s experience. An immediate response from the system is crucial for an uninterrupted and pleasant experience for our users. A good responsive system doesn’t disturb the flow of the user or leave them in alarm.

Curious about

I wanted to know more about … and I found it (in literature, on YouTube, on TED talk, etc.):

It was interesting to me that persuasive design is so powerful. So that when done well can indeed drive users to behave in a certain way. So I listened in a bit on what Tristan Harris, an ethicist (previously an amateur magician and a tech entrepreneur) has to say about persuasive design.

Source: The Magic of Persuasive Design via Stanford eCorner

Harris talks about how to apply an ethical framework to persuasive design to students at Stanford.

He takes the streaks feature on Snapchat (a multimedia messaging app) as an example. Streaks keep count of how many consecutive days two friends on Snapchat sends each other a Snap message. Every day they send each other messages, their Snapstreak gets longer.

Source: Business Insider

In the aforementioned video, a student in the audience answered, when asked what she thought of Snapchat streaks, she said that “from utilitarian perspective, it [Snapchat’s streak feature] increases one’s quality of life and makes one feel more connected to their friends.”

However Harris argues that there is an “asymmetry between the knowledge that the persuaders have and the knowledge the persuadee.”

Harris explains: “The goals of the persuader are different than the goals the persuadee so when the people who make Snapchat do this, their actual goal is: How can i hook you to use the product every day? Because that works really well like the streaks feature is super addictive.

And the goal of the person who’s using it usually, that’s the challenge of ethical persuasion, is people don’t know their own goals. So they actually just sit there and then the persuaders goal infects the persuadee. So now the persuade is like the matrix. There’s a drilled hole in the back and this goal went in: ‘now I need to keep up with these streaks’ and now they actually want that. That’s something that they intuitively independently want. That’s successful advertising. The persuaders goal has become the persuaders goal.

And now they [young users] define their friendship based on whether or not they’re able to keep up their streaks. And if they don’t have their streak they’re no longer best friends. And by the way that’s actually true. So there are children walking around who think that the terms of their friendship are the streaks that they have.”

I found Harris’ perspective very insightful because when designing, designers should strive to design with the mind in mind and design with good intent and transparency. Because persuasion is such a powerful tool — designers should also aim to deliver a design that is not only valuable to the user but truly good for them as well.

Usage in UX design

This is how I can use … in experience design:

  • Create a task analysis — to identify the pain points in user’s journeys as they navigate different paths in the interface. By breaking down the use case task by task designers can better visualize the pathways of the user clicks needed e.g. in a dynamic hierarchical dropdown menu. It might be also worthwhile to follow up the task analysis with a user trialling session with real life users to further check the ease of use of your design.
Source: MacOS via Nielson Norman Group
  • Make your menus more steer-friendly — by keeping them as short as possible. Avoid designing menus that are more than two levels e.g. hierarchical menus. Menus with fewer choices make it quicker and easier for users to visually search through.
Source: Justinmind
  • Be transparent about waiting time — For operations that take a longer, designers should communicate the current progress to users with progress indicating elements e.g. spinners, loading bars, etc…
This golf themed progress indicator tells users that 31% of the progress time has elapsed Source: Smashing Magazine

And this will also conclude my 6 part #universitydiaries series of learning from my degree course, Psychology of Experience. I hope you as a reader enjoyed reading through my weekly learnings and I hope to be back with more insights to share 🤓👩🏻‍💻




UXD/UXR student @THUAS, the Netherlands. Happiest when ideating and munching on Swiss cheese 👩🏻‍💻🧀

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Michèle Huynh

Michèle Huynh

UXD/UXR student @THUAS, the Netherlands. Happiest when ideating and munching on Swiss cheese 👩🏻‍💻🧀

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