Top-Down Processing

The Viking 1 Orbiter, a NASA spacecraft, took a curious photo when it flew past the Martian surface in 1976. The image, taken by its two vidicon tube cameras, showed a landscape pockmarked with craters and shadowed by mesas. The mostly featureless region of Mars named Cydonia was nothing extraordinary, excepting the humanoid face staring up from its surface. First popularized by the book, The Monuments of Mars: A City on the Edge of Forever , by Richard C. Hoagland, this image became known as the “Face of Mars.” The covers of grocery aisle tabloids have celebrated the image ever since.

Based on the pixelated 1976 image, the face appears to some viewers as an expressionless, somewhat androgynous, forward-facing human portrait (see Figure 13-1). They believe the photo shows an elaborate construction built to welcome or warn curious onlookers as they fly past the Red Planet.

In actuality, the “Face of Mars” is a rather ordinary mesa reaching 800 feet high.⁴ And, like any tall thing under sunlight, it casts shadows. When photographed, the broad shadows it created looked like a jawline, deep shadows looked like eye sockets, and small shadows looked like a nose.

Believing the “Face of Mars” is an alien glamour shot or a garden-variety rock pile is a secondary issue. The primary question is why do most of us see it as a face? Our answer lies in a discussion of schemas.

A schema is a mental shortcut, a way to interpret incomplete information. Say you are gazing up at the stars on a clear evening. You marvel at the expanse of the universe and see a flickering light. For a fleeting moment, you witness a few dim flashes streak across the dark canvas of the night sky. You might think it is a star, a plane, or a UFO. However, there is a good chance that the dim flashes are a passing satellite . Many people are unaware that you can view satellites, including the International Space Station, with the naked eye.⁵ Our preconception—our schema—for a light in the sky doesn’t include satellites, but we do have a schema for shining stars, passing planes, and even UFOs. Your schema for a star may have started when a parent pointing to the heavens said, “Look sweetie, that’s a star.” The first time you viewed a plane passing in the night sky, you likely confused it for a star, because your schema for stars was already well established. Later in life, your schema for planes became established, as well. Upon reading this chapter, your schema for unknown lights in the sky now includes satellites, if it didn’t already.

People have a strong schema for human faces. We even have a place within our brains dedicated to processing faces, the fusiform face area (FFA) . Whereas the brain’s visual cortex processes every other visual stimulus (from paper clips to rocket ships), the FFA gains an efficiency through its unique role. A 2009 fMRI study showed that humans can recognize a face in 130 milliseconds,⁶ roughly half the amount of time it takes to blink your eye. Studies show that four-month-old infants process faces almost as quickly as adults.⁷ The noted scientist, Carl Sagan, hypothesized in his book The Demon-Haunted World: Science as a Candle in the Dark that humans evolved a hyper awareness of faces to recognize the emotional states of humans and other animals. The smiling face of a parent indicated a safe opportunity to bond, whereas the snarling face of a predator indicated a strong warning to flee.

From sunup to sundown, our minds sort the world into a series of perceptions. Schemas shape these perceptions, like the gravitational forces of nearby planets, pulling in everything from within their orbits. Some perceptions burn up upon reentry, while others land and become the foundations of new ideas.

Mental Models

Nineteen seventy-seven was a good year. I had just turned seven years old and won a model-building contest at a local hobby store. The prize wasn’t money, but fame—the type of fame one might expect to receive from having your work displayed in a suburban Ohio strip mall. Handbills plastered the store’s front window. Behind the expanse of glass sat a small wooden platform displaying jet fighters, catapults, Wild West stagecoaches, and my model of a P51 Mustang fighter-bomber (see Figure 13-2). It rested atop a field of green-dyed sawdust grass. Each model paid homage to its source, with every plastic piece glued by hand, every decal affixed by tweezers, and every bolt painstakingly painted with a pin. You might be surprised to learn how many similarities are shared between model building and user experience.

In retrospect, the contest afforded the storeowner a free merchandise display; but I received much more in return: for a few days, I mentally transported myself into the seat of a P51 Mustang. Although nearly 40 years have passed, I still remember those daydreams of flying over the countryside of Beavercreek, Ohio.

Surely, we have all had similar experiences when growing up. You imagined being an astronaut, winning Miss America, or living the life of a gunslinger. Yet, just as a nerdy kid like me had no background in flying fighter-bombers, it is likely that you had no direct connection to any of those imagined pursuits. So how could we imagine them so clearly?

We form mental models of perceived experiences. Like flying a toy plane, we construct these models based on our related, past experiences: the books we’ve read, the movies we’ve watched, the conversations we’ve had. We build mental models of software much in the same way.

Google shapes the mental model for search (see Figure 13-3). Likewise, Amazon does for e-commerce; eBay does for auctions; Twitter does for microblogging; and Microsoft Excel does for spreadsheets.

If a mental model sounds like a schema , take comfort that you are not alone in assuming this. People often confuse the two; however, they differ in a few key ways. Mental models include schemata , but also behaviors and outcomes. Whereas a schema may describe a plane, a mental model describes a plane, as well as flying and landing it.

Mental models set expectations. However, expectations are merely contours that we can sculpt into other forms. New experiences need not be strict combinations of past ones, but mental models are often where new ideas take flight.

Just Noticeable Differences

You are a frog. You sit happily in a cool pot of water. You have not a care in the world. The water starts to warm. It is rather pleasant, reminding you of your time in Palm Springs. The water grows warmer. You look around, admiring the sturdy craftsmanship of your new metal home. The water grows warmer. You relax, reflecting on your life as an amphibian. The water grows warmer. You enjoy your unplanned sauna. The water boils... You are no more.

Why didn’t you jump out? One minute you basked in delight; the next minute you boiled in disbelief. You may have escaped if the temperate changes had been more noticeable. Psychophysicists call such a change a “just noticeable difference.”⁹ A just noticeable difference, or JND, is a unit of measurement. It describes the smallest detectable difference between two levels of stimuli.

Bottom-Up Processing

You find yourself walking down an alleyway. It is late. It is dark. You spent the evening with friends at a downtown restaurant. Your car is parked a few streets away . Hulking silhouettes of trash dumpsters and piles of debris line the pathway, as the stench of unfinished entrees and discarded mop water fills the air. You navigate past each starlit obstacle and hear a noise. A footstep. Another follows. You speed up. So do the footsteps. Your shoulders tighten. Your stride widens. Your pulse grows. You gasp and turn and see nothing. It was merely an echo.

Stories of dark alleys are clichés and staples of horror films. The sights, smells, and sounds lead characters into states of fear and panic. Shadows transform into monsters, stenches instill dread, and unidentified footsteps indicate malicious pursuit. In actuality, the protagonists of such stories should embrace a top-down approach to their thinking: we live in the safest time in all human history, therefore what we sense is rarely danger. The 2014 UN Office on Drugs and Crime report states that we have a 1 in 16,000 chance of being murdered.¹³ Considering the average 30-year-old person has greater than one in five chance of living to 100,¹⁴ it would be more rational to worry about your retirement savings, rather meeting your demise in a dark alley.

But our senses can surprise even the most logical of us. Opposed to top-down processing, where we construct perceptions based on general concepts, bottom-up processing constructs perceptions based on sensory data. Listen up. I smell something fishy. This feels squishy. Watch out! Sound, smell, sight, and touch construct perceptions upwards. Sometimes senses aid us; sometimes they trick us. Like victims in a horror movie, we only realize our perceptual errors when it is too late. Yet, we can also leverage bottom-up processing to improve experiences, through which senses become tools to accelerate behaviors , assuage fears, and satisfy users.

Gestalt Grouping

Red represents everything from love to anger, from safety to danger, from Christmas to communism. A red heart shows affection. A red hand shows revolution. A red light tells us to stop. A red exit sign tells us to go. In every case, we sense red in the exact same way. Its wavelength always measures around 650 nanometers.¹⁵ Yet, how we perceive color changes. The conflict between what we sense and what we perceive lies at the core of user experience. We possess a myriad of senses—sight, sound, smell, taste, touch, temperature, and pressure. However, our perception of these senses is often a matter of gestalt.

A favorite word bandied about at dinner parties and in film schools, gestalt describes the whole of something, as opposed to its parts. When you watch a movie, you see action as a continuous motion. One frame at a time, movie stars dangle each other off the bows of ships, avatars fly among floating mountains, and toys tell you their stories. You see this motion in 24, 25, or 48 frames per second. Psychologist call this effect “apparent motion.” You experience each frame (each part), but you also experience the movement (the whole). You experience a gestalt grouping.

Gestalt grouping laws describe how people perceive objects as organized patterns. The laws cover similarity, proximity, continuity, and closure. Of these, two are especially helpful in user experience: proximity and similarity.

Pitfalls of Similarity

Imagine a mobile app with two buttons of similar size and color (see Figure 13-4).

The first button, “View Cat Photo,” raises no eyebrows; pressing the button might display a photo of a cat. Pressing the second button, “Detonate Explosive,” is another story entirely, with presumed dire consequences. You must exercise caution when presenting vastly different behaviors in the same manner. Similarity connotes UX behavior in a linear progression. The first button sets the context for the second button. Viewing cat photos is a safe activity, thereby deescalating the dangerous activity of detonating explosives. To prove this point, let us switch the order of our previous example (see Figure 13-5).

Now the button “Detonate Explosive” sets the context for “View Cat Photo.” Certainly, this button order makes one pause for at least a moment.

Important behaviors command separation within an interface. Checkout buttons, delete functions, and quit without saving are candidates for such treatment.

Within the larger universe of UX, the Law of Similarity¹⁶ affects behaviors across products and services. Users come to expect similarity. Users anticipate searches to behave like Google (see Figure 13-6) and checkouts to perform like Amazon. Users assume everything from password retrieval, to email unsubscribes, to social shares , will perform in similar ways. We should not design everything to be the same, but we should at least acknowledge users’ expectations of sameness. The experiences you design will be compared to many others. And you are outnumbered.

Gestalt grouping transforms random patterns into designed experiences, connecting the detached and highlighting the overlooked. It makes the new feel familiar. Handle gestalt grouping wisely, and you will be in good company.

Selective Perception

Hiawatha Service 332 bypasses the steady state of arterial road traffic between Milwaukee and Chicago. In 89 minutes, the train’s riders depart Miltown’s intermodal gateway and eventually find themselves in the heart of Chicago’s Union Station. Long an early morning refuge for blurry-eyed salespeople and late-night party-goers, Hiawatha attracts a wide assortment of professions, cultures, and hangovers. However, each rider’s trip is unique, because each is a selective perception.

Commuters and tourists alike fall asleep in peaceful unison within minutes of the train’s departure. Gaping mouths and contorted postures fill each carriage like dozens of goldfish placed on blue fabric seats, as the constant hum of the track passes beneath. Dah-dunk. Dah-dunk. Dah-dunk. The rhythm lulls even the most caffeinated to sleep. Some riders doze motionless. Others roll and fidget. They close their eyes. They wear headphones. They curl into the fetal position and form makeshift pillows out of jackets and sweaters. Consciousnesses rise and fall, governed by the lucidity of dreams and the placement of armrests.

Our brains search for stimuli, be it while riding a train or viewing a mobile app. We seek the pleasant and avoid the unpleasant. If our seat is comfortable, we relax and slumber. If light gets in our eyes, we close the shade. Aggravation yields to comfort. Pleasure beats provocation. Social psychologists call this selective exposure, or the “confirmation bias.” We find the messages that confirm our beliefs rather than challenge them. We readily notice ads for products we already own. We eagerly recognize virtues in the political candidates we already support. We unhesitatingly accept compliments about things we already enjoy.

One glowing attribute casts a halo around all others. This halo effect affects everything from interpersonal relationships to international branding. We believe attractive people are also kind. We think profitable companies are also managed well. We will even defend our favorite brands by ignoring their competitors’ advertising.¹⁷ You can experience this phenomenon firsthand: persuade an iPhone user to switch to Android; convince a Ford truck owner to buy a Chevrolet; coax a Snow user to download Snapchat; cajole a Diet Coke drinker to order a Diet Pepsi. Such halos surround us, enveloping our decisions in predictable delusion.

Moreover, we erect psychological barriers to threatening stimuli. Smoking causes nearly one in five deaths.¹⁸ Texting causes one in four car accidents.¹⁹ Unprotected sex causes one in two unplanned pregnancies.²⁰ Yet, even after being exposed to the dangers of smoking, texting while driving, and unprotected sex, a great number of us still smoke, text, and spend anxious moments awaiting the results of a test strip.

Psychological barriers affect the user experience of digital products, as well. A recent Pew Research report indicates that only 9% of social media users feel very confident that their records are private and secure.²¹ However, the user base of such apps continues to grow, totaling 69% of the American public.²² Users weigh the tradeoffs between privacy and utility, though risks and rewards are often perceived selectively. Likewise, as of January 2017, 4% of Samsung Galaxy Note 7 phones²³—the defective and recalled devices that may spontaneously combust and burn their owners—have yet to be returned. Few user experiences carry such dire consequences, but we should note that even possible immolation is not a compelling enough argument to offset some people’s selective perception.

We avoid the pitfalls of selective perception by acknowledging them. Users can even benefit from their inability to fully perceive an experience, thereby focusing on the necessary.

We can also avoid the pitfalls of selective perception by recognizing its triggers. If you wish to buy a car, your perception will become focused on cars. Recognize that the ads and offers you will find are the result of this trigger, even though the information was always there, waiting for you to perceive it. That car commercial you just watched may be more of a selective perception than a true bargain.

As designers, we can intercept these triggers, thereby directing users to what is necessary. For example, imagine someone shopping for a train ticket. He wants to find the best price. His focus is on the ticket’s cost, perceiving it above all other stimuli. He may not notice a train’s departure time. Placing vital information, such as the departure time, next to the price helps the user avoid a costly mistake. He catches the error before it happens, because we anticipated his selective perception.

Like daybreak filtering through a window, perception highlights some stimuli while obscuring others. It sifts through countless sights, sounds, smells, tastes, and touches, transforming what we could experience into what we will experience. Perception shapes our world. Patterns emerge, messages take form, and users awaken.

Key Takeaways

Questions to Ask Yourself