Stimulus Response Compatibility

Stimulus Response Compatibility

Have you ever had someone give you a list of words written in different colored ink and asked you to ignore the word as written and instead say the color of the ink that the word is written in? It isn’t too difficult when you see random words, but it becomes much different when you see the names of colors written in different colors, such as green written in red ink or the other way around. The difficulty with reading the color and not the word in those situations stems from poor stimulus response compatibility. The brain receives a signal in the writing of the word, and has to overcome that signal to say a different color.


Richard Thaler and Cass Sunstein use this as an example in their book Nudge. They also demonstrate stimulus response compatibility using an example of a door with round wooden handles in a classroom that Thaler once taught in. The handles sent a signal to student and anyone else exiting the room that indicated they were intended to be pulled in order for the door to be opened. However, the doors needed to be pushed open. Describing the confusing doors and the poor stimulus response compatibility, the authors write, “you want the signal you receive (the stimulus) to be consistent with the desired action. When there are inconsistencies, performance suffers and people blunder.”


Stimulus response compatibility is crucial in terms of website design, road construction, slide presentations, video games, and any other setting where cues are used to indicate a desired behavior. People need to understand where to click to add an item to a shopping cart, how to scroll through a website, and how to close out of any pop-ups. Drivers need explicit cues for when it is safe to drive through an intersection, and inexplicit cues can help drivers understand when they need to slow down. Visual, audio, and other stimuli can drive predictable responses in people, and they can be used as nudges to help encourage or discourage certain behaviors. Understanding the stimulus you are providing and whether it is compatible with the behaviors you want people to exhibit is crucial.


Most of us probably want to develop good stimulus response compatibility, but we should also note that it can be used to frustrate people and prevent certain behaviors or goal attainment. If you have ever tried to unsubscribe from an annoying email list or newsletter, you may have experienced the challenges of intentionally poor stimulus response compatibility. Instead of having a clear link at the end of the email to unsubscribe, the link might be a dull gray color. The link might take you to a page with unclear directions on what buttons you needed to select to unsubscribe from all future emails. You may have seen a green button prominently placed that re-subscribed you instead of unsubscribed you from the emails, thwarting your plan to declutter your inbox.


It isn’t quite the case that these nudges are methods of mind control, but they do influence our behavior and can shape how we behave, what we learn, and real outcomes in our lives. If we are choice architects, we should recognize what behaviors we are trying to encourage, and think about the subtle cues and stimuli we can present to encourage people to make decisions that are in the best interest of the individual making the choice – as measured and determined by them, not us. Nudges are powerful, especially when a good stimulus response compatibility is in place. Importantly, nudges are not the kinds of roadblocks and obstacles that I discussed in the example of trying to unsubscribe from an email list.
Stimuli, Attention, and What We Notice

Stimuli, Attention, and What We Notice

“Wherever you direct your gaze, you will meet with something that might stand out from the rest, if the context in which you read it were not equally notable,” writes Seneca in Letters From a Stoic.


Quite a while back I listened to a podcast interview with the founder of a music streaming service called Focus At Will. The company is different from other streaming services such as Spotify or Pandora in that they don’t provide stations that have your favorite songs from top artists. Instead, they have stations with altered songs and selected tunes that they believe will help you stay on focus. The idea is that our brains are easily distracted by the human voice, by instruments that mimic the human voice, and by lots of changes in our background. Each time we hear a voice, we are distracted for a fraction of second as our brain figures out whether we need to pay attention to that voice or not. And when the sound in the background changes suddenly, like when a song ends, when a car honks its horn, or when a branch snaps, our brains perk up and focus on our surroundings for a second to figure out if we are in danger. Eliminate these background noises and provide a consistent noise, the company argues, and people will be able to focus.


Seneca’s quote from above reminded me of Focus At Will and the theories behind their streaming. In particular, one of their stations really aligns with the ideas that Seneca lays out in the quote, but from an audio rather than visual perspective. Focus At Will has a station designed for people with ADHD. Based on neurological studies, they argue that people with ADHD have brains that are too sensitive to background noises. For most of us, when a colleague sneezes from two offices over, the sound is detected by our ears and transmitted to our brain which subconsciously decides the noise was unimportant. Consequentially we don’t even notice the noise because it gets stuck with the unconscious brain, never elevated to the level of conscious awareness. For an individual with ADHD, however, their brain is more sensitive to a sneeze from down the hall, and they consciously recognize that noise and are distracted as they think through whether they need to respond to the stimuli or not. This happens with more than just sneezes, and can be hugely distracting for the individual as they are constantly working through stimuli that are easily ignored and unnoticed for most of us.


The solution that most of us would jump to would be to put an individual with ADHD in a completely noise and stimuli reduced environment. The solution of Focus at Will, in line with Seneca’s quote, is to raise the context of other noises to be equally as notable as the disruptions. The streaming service has a station that can be almost overwhelming to individuals without ADHD. There is a flurry of sound (in a musical way – not just random noise) that is somewhere in the neighborhood of heavy metal, demolition derbies, or construction sites. The solution is to raise the level of noise and distraction so that everything is operating at a high distraction level, so that no notable sound stand out.


Personally, I listen to stations like the Chilled Cow Lofi Hip Hop Radio Station when I need to focus on important work. But the idea of what stands-out, what we focus on, what we notice among a sea of stimuli is fascinating. Our brains can be overwhelmed by stimuli, and at the same time, an abundance of stimuli can also bring our attention and focus into a single point, drowning out other stimuli. This is just one more example of how reality isn’t. Our brains construct and create the reality we experience, and how we see the world around us is context dependent, with the level of stimuli playing a role in what we observe and experience.