Good design is not just about making digital experiences useful, usable, and engaging; done well, it’s also aligned with business objectives. Persuasion is an effective tool for unlocking value that your website or app might be missing and having a meaningful impact on sales. Some of the most successful e-commerce services in the world do it, now so can you. When your prospective customer has three or four tabs open on their browser, how can you nudge them towards a sale on your site rather than someone else’s? Or if they’re already planning to buy, how can you entice them to upgrade or add another product? A good place to start answering these questions is Dr Robert Cialdini’s excellent 1984 book, Influence: the Psychology of Persuasion, which examines what drives people to say yes, and how businesses can use these ideas ethically. Surprisingly, the idea of applying these decades-old behavioural science principles to websites and apps seems to come and go out of vogue with marketing and product teams despite studies showing that these triggers have significant positive effects on online purchase behaviour. Applying them might not necessarily involve huge infrastructural investment or refactoring the entire website or app. To begin with, two things are needed: data and management buy-in. I’ll explain what this means in practice, and how you can link it to your site or app, using the principles outlined here. Social proof Of course, we expect a company to say their product or service is amazing; what’s so effective about social proof is that it reflects what other people like us think. A survey by Brand Rated found that 95% of consumers read online reviews before they shop and 58% say they would pay more for the products of a brand with good reviews. You can show social proof through customer reviews and testimonials (ideally with photos or videos for authenticity), or ratings like ‘4.8 stars’ or ‘95% of guests recommend’. I mentioned earlier about how important it is to have useful data: this is where you can apply it. If you’re already asking customers for reviews, share this information to build social proof. The more you know about a customer, the more you can tailor an offering specifically to them based on their peer group: “6 other people from Cork bought this”. To increase trust, you should make reviews verifiable where possible. Reciprocity The principle of reciprocity works on simple human nature: give and you will receive. On your website, this could mean offering a 10% discount for newsletter signups, or including a complimentary item with purchase like a free breakfast with your stay at a hotel. These don’t have to be grand gestures: the smallest value-add nudges users ever closer to saying yes. The offer should be clear and valuable, but don’t overdo it. If every popup offers something more, users may become numb or suspicious. Commitment Commitment builds when users make small, low-barrier choices that align with a bigger decision. Think about how “add to wishlist” or “add email to receive a quote” buttons work: they ease users into micro-commitments before the final sale. Services like Klarna use the same principle, by letting customers take the first step (‘pay nothing today’) and feel invested enough to complete the process later. Booking.com offers free cancellation, which is very effective at deflating a moment of potential procrastination. All you need to do is click the button and worry about it later. Authority Certifications and objective industry-related credentials are a great way to lean on the reputation of other trusted brands, creating authority through legitimacy. Customers are more likely to convert when established institutions or brands vouch for you. Use association badges, trust seals, industry accreditations, or partnership logos. If your business got a stellar writeup in the press, use the logo along with text like ‘As featured in…’. Trustpilot ratings, or even payment provider icons like Mastercard and PayPal are subtle cues that say to visitors: “look who trusts us; you can too”. Be intentional about putting authority indicators in high-visibility areas on your app or site: on checkout pages, page footers, or beside calls to action. Liking People buy from people, or brands they like. Use storytelling, behind-the-scenes content, or relatable imagery to build connection. This is where your brand’s personality shines through. You can achieve this very easily by including photos of your team, and fostering community engagement through comments or social feeds. The trick is to be authentic. For instance, don’t force your down-to-earthness if it doesn’t feel right, don’t come across as overly conversational if it doesn’t suit the brand tone or voice, and don’t overdo stock imagery. Scarcity Creating a sense of FOMO uses urgency to nudge users closer to a sale. Hotel booking sites and airlines use this tactic all the time with a carefully placed data point close to the price (“only three seats left at this price!”). Scarcity can be based around quantity, or time-related, like a 48-hour flash sale. Use with discretion: artificial scarcity could see the comments and ratings take a tumble, and you also also need to be mindful of regulations or guidelines that apply in your industry. Unity People tend to be more loyal to people they identify with, such as members of their own family or people who share their belief system. This is where organisations can tap into that sense of belonging and speak to their values. For example, you could say “Like you, we value a clean environment”, or “We too believe that families deserve value”. Again, authenticity is key here and only profess things you are willing to stand by or demonstrate in your actions. Use it in product descriptions or About Us content. Persuasion principles in practice Now it’s time to put these principles into practice. Before embarking on a persuasion project, check that you actually have the data you need to ensure that your persuasion points are accurate and honest. For example, can you surface real-time remaining inventory data on your website or app? Steer away from ‘dark patterns’ where persuasion techniques create artificial urgency or mislead users. Trust is hard won and easily lost: if your brand values emphasise trust, the last thing you want to do is erode it by giving consumers a reason to doubt your good faith. Persuasion shouldn’t be guesswork. Implement A/B tests: compare checkout pages with and without testimonials, or run variants with different authority signals. Review your analytics: which changes have the biggest effect on your conversion rate, average order value, or retention? You can take an incremental approach and work on one or two principles at a time, and measure the progress of each. Needless to say, liaise with the commercial teams to ensure that any discounts offered align with strategy. For me, persuasion should be a persistent aspect of your online presence and evolve as your technology and regulation around it does. I’ve seen first-hand how it helps conversion metrics. As the wins from Persuasion start to add up to a noticeable increase in sales, keep enhancing and iterating: A/B test, get closer to customers through real research, analyse what works across global markets, engage experts, and continuously improve and evolve.