In his book Thinking, Fast and Slow, Nobel Prize-winning economist Daniel Kahneman describes 2 modes of thinking, using terms coined by psychologists Keith Stanovich and Richard West:

System 1 operates automatically and quickly, with little or no effort and no sense of voluntary control. System 2 allocates attention to the effortful mental activities that demand it, including complex computations. The operations of System 2 are often associated with the subjective experience of agency, choice, and concentration.

Much of our decision making and daily operations are dictated by System 1. System 2, being the “Effortful System” prefers to be used much less frequently. Some say it is lazy!

Cognitive Ease and Cognitive Strain

Every moment, a person's brain is running diagnostics to determine if it can continue using System 1 or if it needs to tap into System 2. If all is well and running as expected, we are in a state of cognitive ease. If we feel uneasy, uncertain, and/or sense a problem, we engage System 2 and switch to a state of cognitive strain.

Numerous psychological studies (a number of which are described in great detail in Thinking, Fast and Slow) have identified various stimuli that cause us to switch from cognitive ease to cognitive strain. For example, reading complicated instructions, listening to simultaneous conversations, viewing text that is in a small font or has poor contrast, and even being in a bad mood all generate cognitive strain. When user experience specialists facilitate usability studies, they observe people reacting to website and application designs. They watch body language and listen for changes in tone of voice and tenor of comments as participants think aloud. In effect, facilitators determine when participants move into a state of cognitive strain and what the stimulus may be.

Negative Consequences

In many of our studies, we have witnessed that when people have to exert more energy in order to find a piece of information or manipulate a feature, they can become more vigilant and suspicious. Instead of just putting an item in the shopping cart and flying through the checkout, they may want to examine other options — some of which may not be on your site. They may start to question the credibility of your content, the reputation of your company, and the honesty of consumer reviews. The result of this lack of confidence may be a decrease in your visitors taking the actions you want them to take (a.k.a. desirable actions).

Four Navigation Attributes/Components that Cause Strain

The following examples are from independent studies we have conducted in the past 5 years. To their credit, each of these sites have removed the strain-inducing navigation attributes, and we’d like to believe it’s because (1) they have awesome UX teams, and (2) they conducted usability testing and found the same issues that we point out here.

1. Thin, horizontal, roll-over activated menus: Testing users’ fine motor control (and patience)

When I am teaching our course on Navigation Design, I like to joke that I’ve asked my colleagues to stop sending me videos of study participants struggling with this style of navigation, because I’ve already got quite the collection. Thin, horizontal, roll-over activated submenus are simply difficult for people to use — especially if the item they want is at the far end of the submenu. This is because they need to keep their cursor within the area of the submenu or else the choices disappear. The thinner and longer the menu, the more coordination and concentration is required to avoid accidentally dismissing it.

On Keurig’s site, the participant was trying to access the e-Gift Certificates link. It took her 6 times to select the link, because she had to keep the menu active and visible by maintaining a perfectly horizontal scroll without wandering off the trigger area. This ended up becoming a test of her motor skills instead of a navigation tool! People should not have to dedicate this much mental (and physical) effort to navigate.

Advocates of this type of menu argue that users don’t want the content in the body of the page to be covered by the exposed menu. However, in this example, the only content that would be covered would be the images in the hero space. Also, when people decide to activate a menu, they seek routing options and rarely need the body content visible (especially a hero image) in order to make an informed selection.

Fixed:

The site now features a well-structured mega-menu that does not require excessive motor effort to use.

2. Unfamiliar labels: Forcing translation of your creative nomenclature

Catchy, unique labels may seem attractive, but unfamiliar terminology can actually drive users away. In the Dale Carnegie example below, Inquire, Involve, Innovate, and Impact are steps to help define training methods for their clients, but prospects don’t know that. Using those labels as navigation tabs may seem like a good idea to everyone in the company, but outsiders need to know the process before the “I” words have any meaning.

Remember: Your methodologies, ad campaigns, and slogans may change. You should never use nomenclature tied to these as organizing elements in your information architecture and navigation labels. Defining your IA is exceptionally difficult when you are limited to a pre-defined set of high-level labels. It’s like jamming a square peg in a round hole.

Fixed:

The site now features a page defining the process and the “I” terms are no longer used as navigation buttons.

3. Redundant links on routing pages: Increasing the perceived number of choices

Cornell University’s Johnson School website was tested as part of our eyetracking study in 2010. The body of this routing page was well structured, containing links with succinct descriptions that explained the resulting content. However, the links in the left-hand submenu were repeats of the links in the body of the page. When people were evaluating link options, they had twice as many choices to scan because they didn't know these were redundant until they had committed the time to fixate on and read them.

There is a prevailing belief that duplicating links is not harmful, but it is. Designers know these links are duplicates, but users do not. So, they often end up scanning both sets of links — effectively doubling the amount of analysis they need to conduct to select the best link. Repeating links burdens your visitors.

Fixed:

The site no longer repeats the same links in the page body and the left-hand submenu.

4. Overly incremented sliders: "Fun" tools that become obstacles

For a while, everyone wanted sliders on their sites. In many cases, they are simply unnecessary. In Samsung’s case, there were only 28 televisions in the Plasma TV section, but the sliders — adjustable for the start and end ranges for both price and screen size — featured increments for which there were no matches. Also, there was no indication of which ranges would be fruitful.

When we tested Samsung’s site, one participant looked at the faceted search sliders and said, “That is actually quite a good feature." He then spent almost 2 minutes of great effort manipulating all 4 end points of the sliders to get some results. He wasn't successful and most of his attempts resulted in the “Sorry” screen. In this case, sliders were an effortful overkill.

Fixed:

The most recent version has removed the faceted search altogether, because there simply aren’t enough products to warrant it. Instead, people can use the filters above the listings.

Keep an Eye Out for Cognitive Strain

Cognitive strain is noticeable when you are watching people interact with an interface; that’s why we always recommend some type of moderated testing as part of your research, measurement, and monitoring activities. Recognizing and replacing design elements that require too much effort from your users can offer tremendous bottom-line value to your organization.

Learn more in our full-day Navigation Design training course.