July 1, 2026 · 6 mins read

The psychology of digital design: Influence, emotion & ethical practice

In a recent webinar on the psychology of digital design we explored how people make decisions, how it impacts online experiences and why those decisions are often far less rational than we like to believe. The truth is, as humans our decisions are irrational.

Cognitive biases

The reason we make these decisions is because our brain takes short cuts. Known as cognitive biases.

The fascinating thing about cognitive biases is that they’re not signs of stupidity. They’re evidence that human brains evolved for: speed, survival, social belonging, and efficiency. Which is lucky, because if we fully evaluated every button, banner, and pricing table we saw in a day, we’d never get anything done.

Deceptive Design

Unfortunately, cognitive biases also make us vulnerable to being persuaded into making decisions that aren’t in our best interests. Unethical designs that do this are often referred to as deceptive design.

When using cognitive biases and psychology to influence users, it’s important ensure your designs are ethical.

We’ve all seen examples of unethical designs such as:

• Confirm shaming – When buttons and links are framed to shame users into choosing an option. For example; action buttons can be framed as ‘I’m so rich I don’t care about saving money’ when asking user to sign up for email campaigns.
• Roach motel – when websites and apps make it really easy to sign up for a service or subscription, but considerably harder to cancel it. Users often have to phone up to cancel or navigate through very complicated screens.
• False Hierarchy – using colour, size and placement to nudge users into selecting its preferred option. For example, buttons can be made more prominent when purchasing products with insurance, or with credit.

In some examples, a large call to action may be used for a preferred option, while alternative options are made much less prominent through their size, placement or styling.

It’s important that when we use psychology of cognitive biases in our designs, we need to be aware of deceptive design and not tricking users into taking an action that is not in their best interest.

This article reviews some of the many cognitive biases, how they can be applied, but also some of the pitfalls to avoid.

Scarcity

The fear of scarcity can drive demand.

In a study by Knishinsky in 2000, wholesale beef buyers were told that supply would be scarce in the coming months. The result was that sales doubled. However, when certain wholesale buyers were told that this information was a secret and only being divulged to them, sales increased 6 times.

Scarcity can also imply something is better, or even exclusive. When Google Mail rolled out the 10-megabyte version of Gmail, they blamed ‘technical constraints’ as the reason why not everyone could get it. You had to be invited, and then you could invite 3 friends. The service spread fast virally with help of its scarcity and recommendation system.

The most common use of scarcity in retail is to highlight how many items are left, or how long until a specific sale ends. But are these prompts helpful and informative to stop customers from missing out on something, or are they deceptively trying to put users under pressure to make a decision that may not be in their best interest?

We asked our webinar attendees to rate whether the following types of scarcity are deceptive design or not:

• "Only a few left"
• "A specific number left"
• "Offer ends in a specific time"
• "Offer ends soon"

The results showed:

• 86% of our attendees thought ‘only a few left’ was deceptive
• 70% of our attendees thought ‘a specific number left’ was deceptive
• 49% of our attendees thought ‘offer ends in a specific time’ was deceptive
• 42% of our attendees thought ‘offer ends soon’ was deceptive

Social proof

In ambiguous situations people make the assumption that surrounding people possess more knowledge about the situation and deem the behaviour of others as appropriate or better informed.

We are also more likely to behave like people we consider similar to ourselves.

Texas in America ran an unsuccessful and expensive anti-litter campaign in the 1980’s. Part of the reason it didn’t work was because young Texans were not impressed with the bureaucratic elite telling them to pick up after themselves, so they just ignored it.

They then ran a now infamous campaign called ‘don’t mess with Texas’.

The campaign used Texas cowboys to encourage people not to litter. People associated themselves as being like the Texas cowboys initially, then they made it a patriotic thing to do. As a result, litter reduced by 29% in the first year and 72% over the next 6 years.

There are dozens of examples of how social proof has been used to change behaviour including:

• Transport; electronic tickets instead of paper tickets
• Banks; switching to electronic statements instead of paper statements
• Blood donations; increasing the take up rates in colleges
• Energy consumption; highlighting neighbours' consumption
• Hygiene; getting hospital workers to wash their hands more often
• Health; reducing drinking habits amongst students
• Exercise; getting people to take the stairs instead of the elevator

There are also lots of ways to increase website conversions using social proof:

• Brand affiliation from large organisations that use and endorse your product
• Customer reviews and feedback on your product
• The number of users and how often they use your product, or even what they use your product for
• Testimonials from people in authority advocating your product
• Community badges that show high levels of engagement with your product

However, overuse of social proof can be confusing, less compelling and crowded.

Imagine if every Airbnb house you looked at was a ‘rare’ find. You’d soon lose trust in what was and what was not a rare find.

So be careful with how you use social proof, because if everything is popular, then nothing is popular. Especially if you use different methods of measuring what popularity is.

The most common use of social proof in retail is to highlight if something is rare (because it’s always being booked by someone else so never available), if lots of people are adding it to their basket, or if lots of people are actually buying it.

But are these prompts helpful and informative to stop customers from missing out on something, or are they deceptively trying to put users under pressure to make a decision that may not be in their best interest?

We asked our webinar attendees to rate whether the following types of social proof are deceptive design or not:

• "Rare find"
• "In basket"
• "In demand"

The results showed:

• 72% of our attendees thought ‘rare find’ was deceptive
• 63% of our attendees thought ‘in basket’ was deceptive
• 58% of our attendees thought ‘in demand’ was deceptive

Conclusion

What’s deceptive and what’s not deceptive is not always agreed upon. But some patterns clearly are intended to deceive users.

We need to be aware of deceptive design and not tricking users into taking an action that is not in their best interest when implementing design, especially those that apply cognitive bias psychology.

• Experience

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