As human beings we often feel that we are rational and responsible actors in our own lives who make sensible, well thought out decisions based on logic. We hope that our users act this way, too.

Actually, psychologists tell us, more often than not, this isn’t the case. We still rely on the more animalistic and instinct driven decision-making of the limbic system, which we then post-rationalise using our more logical frontal lobe. Post-purchase rationalisation (also known as choice supportive bias) is the tendency to retroactively give positive attributes to an option one has selected and to demote the forgone options. For those in the app space that goes a long way to explaining why users often become so emotionally attached to and defensive of their choice of iOS or Android!

In this article, we’ll explain Dual Process Theory and explain how applying this framework to app UX design can help you to influence your users by using their subconscious decisions.

An overview of Dual Process Theory - System 1 and System 2 Thinking

The limbic system is the part of the brain involved in our behavioural and emotional responses, especially when it comes to behaviours we need for survival: feeding, reproduction, caring for our young, and fight or flight responses. Psychologist and Nobel Prize winner Daniel Kahneman describes this kind of thinking as “System 1” thinking in his book Thinking Fast and Slow. In the years since its release in 2011, the book has revolutionised the way marketeers approach marketing and advertising but has seen a slower path to acceptance in the field of digital UX.

System 1 thinking, says Kahneman, is instantaneous and driven by instinct or prior learning while being less energy taxing and quicker than engaging the logical frontal lobe (or “System 2”). Because of this the always efficiency-seeking human brain allows our System 1 beliefs, biases and intuition take the driving seat for many of our choices, even when we believe we’re making decisions rationally. It’ll often only engage the more costly System 2 for the relatively easy task of post-rationalisation.

Now that we know how this works at a high level, how can we begin to use this knowledge to make sound design decisions? Here are 3 tips to keep in mind.

1) Don't confuse "System 1" thinking with emotional thinking

Often when interpreting Kahneman’s work it’s tempting to fall into the trap of treating System 1 thinking as purely emotional but this distorts its true meaning. Take for example the idea of picking up your usual brand of milk while you’re in a rush and out shopping. It most likely didn’t take any real thought or involve a strong emotional bias towards that particular brand, yet your System 1 thinking autopilots you towards it. It’s the same thing that happens with muscle memory actions like riding a bicycle or driving a route you’ve driven many times before. In fact, we’ve likely all had the experience of driving to somewhere we’ve been several times and not really remembering how we got there.

From a UX design perspective, this opens up a world of opportunities around using familiar design cues and page placement to encourage particular actions based on user expectations. This can facilitate a user reaching your preferred outcomes through easy-to-use and familiar processes.

2) Encourage desired behaviours, but avoid "Dark Patterns"

On the flipside though I’d certainly not encourage malicious UX practices or utilising so-called “Dark Patterns”. These are user interfaces that have been carefully crafted to trick users into doing things they don’t want to do and often supplant user value in favour of shareholder value.

Take a moment to look at the window below, which recommends that the user applies an update to Windows 10. Think about how you would cancel the recommended update if this was something you didn’t want to do.

If you would have clicked the “x” button in the top right hand corner then you’re wrong. Though in every other circumstance you’d ever see a “x” button in the top right hand corner in Windows you’d be correct. In fact, Microsoft had completely changed the use from the perceived and commonly understood “close the window and cancel any potential action” to “close the window and automatically download and install the update”. Unsurprisingly this led to a number of people downloading the update on metered connections and incurring charges, as well as annoying users who simply wanted to remain on an older version of Windows.

As much as this dark pattern likely led to a number of users doing what Microsoft wanted them to do, in this case downloading Windows 10, it also led to a number of incredibly angry users and a plethora of bad press. Encouraging a user to do something they may want to do by utilising good UX practices and forcing a user to do something they don’t want to do by using Dark Patterns are not dissimilar in terms of the skills the designer puts into practice. They are, however, poles apart both ethically and in terms of a good customer experience.

3) Design for intuition, back up with content

Intuition can often be the driving force behind the way we use digital products and it’s not something that can be dismissed lightly as a buzzword or fad. Intuition is built deeply into everything we do in both the physical or digital space. It’s the automatic recognition of past experiences that guides our hand during our current actions.

However, though we’ll often follow our intuition to a certain point (and this can be facilitated by UX design), there frequently comes a point where the user will engage their System 2 thinking and begin to try and rationalise their actions. It may be right before clicking the buy, register or subscribe button; it could equally be at some earlier point in the process. Whenever it occurs, this is the moment where a user might begin to look more critically and seek to find something that justifies their actions. This is also the point at which content becomes king.

High quality informative content backs up the statements you’ve made and the journey you’ve (hopefully) taken your users on thus far. Depending on the perceived cost in terms of data, time, cash or something else, you may need more or less content to remove these obstacles.

A business that trades almost exclusively in bespoke mobile applications that cost tens of thousands of pounds (like ours) may need to produce a wealth of high quality and relevant content in order to show users their capabilities before they’ll be willing to commit to even an emailed enquiry or subscription to a mailing list. Businesses like a social media giant that well known and (generally) trusted may only need to reinforce their core offering and offer a quick and easy sign-up before users are willing to hand over their personal data. And of course there is everything in between! Working out the correct combination of content, instinct and ease of use is key.

Remember: System 1 and System 2 are often used in tandem

A small caveat to all of the above is that often it’s treated as though System 1 and System 2 are completely separate processes with System 1 blazing a trail while System 2 swings into action after the fact to clean up the mess. This is unfortunately a simplification and a generalisation that UX designers need to avoid falling into.

A user will use both systems interchangeably frequently throughout their journey looking for small hints of where to go next in the UX or teases of the juicy content hidden just out of sight. In fact, often the impression of content can mean as much as the content itself. At a high level the way to appease both systems at once is to offer familiarity and ease of use while also showing glimpses into the power of your solution and the depth of your credentials.

Before putting this into practice

This article highlights just a few of the key lessons we’ve taken from Dual Process Theory but this is by no means all there is to take from it. It’s also important that these learnings are put into action in conjunction with a sound understanding of UX design practices, user behaviours and how they interact. See “How to get users to do what you want” for an intro on these.