In the Midwest, you can find hiking trails that are open all year long. Ohio offers some of the finest. Scorching summer months give way to crisp falls. As winter unfolds, tree-lined rivers freeze into slabs etched by the footprints of thrill-seeking deer. Early spring is lovely. Once barren timber thickets explode with dense foliage and wildflowers, creating an eight-million-acre salad of black walnut, white ash, purple coneflowers, and other ingredients, the most unique being a fruit tree called the pawpaw .
Artist’s rendering of pawpaw fruit
A quick Google search confirmed that pawpaw were real. Then I found one. Now, I find them all the time. Despite hundreds of hours hiking in the Midwest, I had never noticed the odd fruit tree growing off-trail. Though the pawpaw were always there, I was blind to their existence.
Inattention Blindness
In the 1970s, an American psychologist named Ulric Neisser conducted a study on why people sometimes overlook easily seen information.1 Psychologists refer to this phenomenon as inattention blindness or selective attention. Researchers have replicated Neisser’s study numerous times, but Harvard University’s variation2 is the most well known. Christopher Chabris and Dan Simons asked the study participants to watch a video showing basketball players passing a ball and to count the number of passes made by players wearing white.
Please watch the video before reading further. You can view it here: https://goo.gl/L7RRWo .
The video is a little over one minute long and ends with no apparent fanfare. Half of the study participants did not notice anything unusual with the video; they watched players passing a basketball. The other half were surprised to see a gorilla stroll across the screen. Were you? When people pay attention to one activity—be it counting basketball passes or submitting an online form—they are less likely to notice anything else.
Our minds act like a sieve, filtering an endless stream of sights and sounds. One filter is frequency. Along with Neisser’s observations, another research study by Dr. Andrew Bellenkes revealed that people are less able to notice something when it happens infrequently.3 You may be surprised to learn what people tend to overlook when using digital products. Instructions sit unread. Buttons lay untapped. Links remain unfound. Gorillas stroll by unnoticed. Although such failures complicate digital experiences, they are only a small part of a much larger set of processes.
Automatic and Controlled Processing
When we talk about attention, we describe how our minds process information. Our mental processing is both automatic and controlled.
Automatic processing handles routine and predictable tasks, such as driving down an open highway. The environment whizzes past us, never requiring us to take much notice. Trees. Fields. Cows. More trees. More fields. More cows. Minutes fly by with hardly a passing thought; yet our minds keep the car on the road, like an invisible chauffeur.
Controlled processing commands more mental resources. If automatic processing is akin to driving a car, controlled processing is akin to texting on a cell phone. We can do either. However, if we do both at the same time, the consequences can prove disastrous. To avoid a sudden obstacle while driving, such as a child crossing the road, requires additional mental resources. They short circuit processing and transform an innocuous text message into a roadside tragedy. Your chances of being in a car accident multiply fourfold if you are driving and texting, which is the equivalent to driving with a .08 blood alcohol level, according to the National Highway Traffic Safety Administration.4 We all must steer clear of the collisions between controlled and automatic processing.
You employ both forms of attention when using an application. Familiar experiences become increasingly more automatic. Think about how you zoom past Terms of Service agreements. People rarely read them. A 2008 Carnegie Mellon University study indicates that we see nearly 1,500 of these agreements each year.5 Yet, such agreements can describe practices ranging from hacking indemnification to recording your phone calls. Like trees and cows whizzing past our car windows, so goes our security and privacy.
Unfamiliar experiences require controlled attention. Navigating a new application can feel a lot like a treasure hunt. You search for products. You consider a purchase. You add to your cart. Over time, some of these actions become automatic through repetition, but complex actions require some controlled processing regardless of how many times you do them. Many e-commerce websites have nearly perfected the transformation from controlled to automatic processing. Websites, such as Amazon.com, remove persistent navigation to reduce the user’s controlled processing needs. After all, one person’s controlled processing is another person’s sale.
Stroop Effect
When you read this sentence, contrasting lines visualize within your brain’s occipital lobe. The back half of its cortex recognizes individual letterforms and pattern combinations of letters. In near parallel, predictions and recognition of words generate within areas of your limbic system and frontal and temporal lobes. Areas with names more fitting for microbreweries than neuroanatomy, such as Wernicke’s, Broca’s, and Geschwind’s, take over and determine meaning and pronunciation. At any stage in this process, new information may intercede, and your coherent thought can be lost in a hazy static.
You expend cognitive resources when viewing information. When something confuses you, the cost is even higher. Your reaction time slows, which a Stroop test proves. Developed in the late 1920s by the American experimental psychologist J. Ridley Stroop, the Stroop test6 demonstrates the cognitive interference caused by competing stimuli. Consider the following example. Read aloud the TEXT COLOR of the following words:
You likely said the text color of item #1 was black, and hesitated on item #2. Both lines of text use black typography; however, item #2 reads, “White”. Competing stimuli can cause a momentary dissonance for users, akin to a cognitive highway pileup. If two words and one color can confuse, imagine the possibilities of a software interface, with its multitude of buttons, links, images, and words. We are lucky that users have short attention spans.
Attention Span
Attention span fluctuates widely, based on age, culture, and context. Several studies estimate that sustained attention lasts for approximately 10 minutes.7 You demonstrate sustained attention when listening to a lecture, reading a book, or watching a movie. Focused attention is fleeting—sometimes it lasts several minutes, sometimes only a few seconds. Hearing an email alert diverts us momentarily; replying to an email diverts us considerably. After too many diversions, and our flow is interrupted.
Key Takeaways
Inattention blindness causes users to sometimes overlook easily seen information.
Users are less able to notice something when it happens infrequently.
Automatic processing handles routine and predictable tasks.
Controlled processes command a user’s attention.
Unfamiliar experiences and complex actions require controlled attention.
Users expend cognitive resources when viewing information.
The Stroop effect results when competing stimuli cause a cognitive interference.
Attention span fluctuates based on a user’s age, culture, and context.
Users’ sustained attention lasts for approximately 10 minutes.
Questions to Ask Yourself
What do my users see but do not notice?
How frequently does an event occur within an experience?
What about an experience is routine and predictable?
What about an experience requires focused attention from my users?
What else competes for my users attentions?
Do users view any contradictory information within an experience?
What is the expected duration of an experience?
How often is an experience interrupted?
Am I unnecessarily interrupting users?