What every designer needs to know about people

Behavioural psychologist Dr. Susan Weinschenk (@thebrainlady) teamed up with the folks at UserTesting.com to offer a free webinar about some of the things designers have to keep in mind about the way our brains work. Weinschenk is the author of 100 Things Every Designer Needs to Know about People (as well as the upcoming book How to Get People to Do Stuff). She couldn’t cover all hundred of her points in the webinar but gave us a run-down of ten of her favourites:

10. People pay attention only to what is salient

Weinschenk showed us a photo of several pennies that had its components—the year, the face, etc.—shuffled around into various positions and different directions. Even though we all handle pennies practically every day, it wasn’t easy to identify which was the correct penny in the photo. Weinschenk used this demo to show that people don’t see everything in front of them; they’re going to notice only what’s most important or most interesting to them.

9. People use peripheral vision to get the gist of the scene

Research by Adam Larson and Lester Loschky published in the Journal of Vision revealed that we can identify objects in the periphery more quickly and accurately than we can identify objects in our central vision, particularly if the information we’re receiving is emotionally charged or may indicate danger. We tend to process stuff that’s in the periphery unconsciously. A lot of design is focused on the central vision—what’s considered “prime real estate” in design—but Weinschenk suggests that we shouldn’t neglect the space around the centre and could use it to evoke a certain emotional reaction in the user.

8. Readers assume that if an instruction is written in a hard-to-read or overly decorative font, the task it’s asking you to do will be hard

Weinschenk notes that there isn’t much difference in the way we read serif versus sans-serif type, as long as it’s large enough and readable. If an instruction is in a hard-to-read font, however, not only do users overestimate the amount of time the task would take, but they are also less likely to follow the instruction, reducing compliance.

7. Miller’s Law is an urban legend

Miller’s Law states that we can store 7±2 items in our short-term memory. More recent research shows, however, that we can really remember and deal with only three to four items at a time.

6. Too many choices can be demotivating

People love to have choices, but having too many can turn them off. Sheena S. Iyengar of Columbia  University and Mark R. Lepper of Stanford published a study in which they offered one group of consumers a choice of tasting six types of jam and another group a choice of twenty-four choices. Although only 40% of the first group stopped to taste the jam, compared with 60% of the second group, 30% of the tasters purchased jam, compared with 3% of the tasters offered more choice. This point is especially important when considering navigation or know how many items to show on one screen.

5. Most mental processing is unconscious

Daniel Kahneman, author of Thinking, Fast and Slow, documented two levels of thinking:

  • System 1 thinking is fast, intuitive, effortless
  • System 2 thinking is analytical and takes conscious effort. (This is what you do when you’re solving a complex math problem in your head, say.)

Most of the thinking we do is System 1 thinking (System 2 thinking is something we have to engage, and when that happens we have a physiological response: our pupils dilate). As a result, most users are susceptible to priming.

Numbers are powerful priming tools; Weinschenk gave the example that saying “Limit 12 cans of soup per person” compelled consumers to buy an average of seven cans, whereas saying “No limit” compelled consumers to buy an average of three cans. Seeing the number 12 primed them. This point is particularly important when it comes to money, because researchers have discovered that the presence or discussion of money changes people’s behaviour. Weinschenk encourages us to build a relationship with a client first, before mentioning the price of a product or service.

Interestingly, Weinschenk told us that if a riddle or puzzle is written in a hard-to-read or overly decorative font, people get it right more often than when the same riddle is in a readable font, suggesting that the decorative font triggers System 2 thinking. She proposed the radical idea that you should use harder-to-read fonts when you want a user to stop and think carefully about something.

4. People have mental models

People come into new situations with preconceptions and expectations based on their past experiences. Everything has an interface, and that interface conveys the model on which the product is based. The better you understand that mental model and create your product to conform to it, the easier your product will be to use. Weinschenk suggests that, before you do any actual design work, you build in a step to purposely design a conceptual model that matches your user’s mental model.

3. We have two types of communities: those with weak ties and those with strong ties

Anthropologist Robin Dunbar analyzed the optimal size of a community of various species and applied the model to humans. For us, a community of 150 people or fewer is usually a “strong tie” community—we know all of the members personally, and we know the relationships between members. Falling outside of these criteria are “weak tie” communities. “Strong” and “weak” are used as anthropological terms here; strong isn’t better than weak, but designers should be aware of what kind of community they’re designing something for.

2. Speaker and listener brains sync together

Researchers Greg J. Stephens, Lauren J. Silbert, and Uri Hasson discovered that when a speaker successfully communicates something to a listener, their brains sync up: functional MRI scans show that the same areas of the brain light up in both parties, an effect not seen with writing and reading. Incorporating multimedia in your communications—audio in particular—is much more powerful having than text alone.

1. There’s a part of the brain that makes us focus on faces

The fusiform facial area (FFA) is a part of the brain that processes visual information about human faces. Faces can instantly convey emotional information and so are very powerful images for designers to use. Weinschenk showed us that as a corollary, images that distort the normal proportions of a human face can be extremely off-putting.


Many of these points have interesting implications for editors and plain language specialists. I’m especially intrigued now about the threshold at which System 2 thinking kicks in. Weinschenk showed that System 1 thinking often leads to the wrong answer when a problem is logically tricky. How can we improve our communications so that we can ensure the correct message gets through without having readers engage their System 2 thinking? And how do we, along with designers, find fonts that will spur System 2 thinking when appropriate but that don’t reduce user compliance?

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