It's the Law
Toolbox
The Other CS (Cognitive Science)
Make It Accessible
To Be Human Is To Err
100

This law states that the time to acquire a target is a function of the distance to and size of the target.


What is Fitt's Law?

100

A researcher meets with participants one-on-one to discuss in depth what the participant thinks about the topic in question.

What are user interviews?

100

The number of tasks people are good at attending to at a time.

What is one?

100

In order to be considered Large Print, font size must be this size at minimum.

What is 18pt font?

100

4% of people say clicking on a suspicious attachment is not a big deal.

What is phishing?

200
This law states that users spend most of their time on other sites, which means they prefer your site to function similarly to other sites. 

What is Jakob's Law?

200

Groups of 3–12 participants are lead through a discussion about a set of topics, giving verbal and written feedback through discussion and exercises.

What are focus groups?

200

These are a natural way for people to process information. These make information understandable, interesting, and memorable.

What are stories?

200

9% of men and .5% of women are this.

What is color-blind?

200

A time-delay feature can help guard against this dreaded office faux pas when you intend to send an email to one person but instead send it to many.

What is reply-all?

300

This law states that the time it takes to make a decision increases with the number and complexity of choices.

What is Hick's Law?

300

A device is configured to precisely measure where participants look as they perform tasks or interact naturally with websites, applications, physical products, or environments.

What is eyetracking?

300

People believe that things that are close together belong together.

What is the proximity principle? (Will also accept: Gestalt's principles)

300

The minimum color-contrast ratio required for normal text to meet WCAG accessibility standards.

What is 4.5:1?

300

This nuclear disaster occurred in 1986, the cause attributed to reactor design flaws and a serious breach of protocol during simulated power outage safety test.

What is Chernobyl?

400

This law states that users often perceive aesthetically pleasing design as design that’s more usable.


What is the Aesthetic Usability Effect?

400

A method of scientifically testing different designs on a site by randomly assigning groups of users to interact with each of the different designs and measuring the effect of these assignments on user behavior.

What is A/B testing?

400

You are most likely to remember what was seen and heard at the end of a presentation.

What is recency effect?

400

Labeling of functions such as links, buttons, and controls should be consistent, and the expected function should be predictable from the label.

What is consistency and predictability?

400

NASA lost at least $125 million Mars orbiter in space because the engineering team used metric units while another used these kinds of units for a key spacecraft operation.

What are English? (Will also accept: Imperial or SI units)

500

This law states that productivity soars when a computer and its users interact at a pace (<400ms) that ensures that neither has to wait on the other.

What is the Doherty Threshold?

500

Analyzing the record of screens or pages that users clicks on and sees, as they use a site or software product; it requires the site to be instrumented properly or the application to have telemetry data collection enabled.

What is clickstream analysis?

500

When you are interrupted while listening to a presentation, you are most likely to remember the beginning and forget when came after the interruption. 

What is the suffix effect?

500

A design technique that involves showing only the least amount of information or functions necessary for a given task or purpose, to avoid overloading the user with information.

What is progressive disclosure?

500

In 1988, this U.S. Navy ship mistook a commercial airliner for a hostile military plane, and shot it down, killing 290 passengers and crew onboard. 

What is the USS Vincennes?