This little blue book was compulsory reading at uni – and it’s been my north star ever since

It was 1996, and I was in my final semester of uni. The home stretch.?

By then, I was working part time in a marketing agency and already felt like a full-fledged marketer. Little did I know how much I still had to learn (#YoungAndClueless). And little did I know that I was about to complete the most practical and memorable subject of all.

That subject was called ‘Sales & Negotiations’. And to my delight, I only needed to buy one book to study it: Influence by Robert Cialdini.?

From the moment I opened the book, I was captivated. (And not just because it was a world apart from all those thick theoretical marketing textbooks I’d become accustomed to.)

This unassuming little blue book explores the psychology behind why people say ‘yes’ – breaking influence into 6 principles that are just as powerful in marketing and business as they are in everyday life.?

As an almost marketing and psychology graduate, I felt as though this book was the perfect fusion of my two qualifications. And I was right. I’ve referred back to it – yes, I still have the original paperback from 1996 – countless times over the course of my career.

Below, I walk you through all 7 principles with examples and suggestions on how you could incorporate them into your marketing and business communications. (Well done to those paying attention. That’s right, Cialdini’s 6 principles grew to 7 in 2021 when he added one more.)

Let’s go.

1. Reciprocity: Give a little, get a lot

Humans are wired to return favours. We simply hate to feel indebted to others.

It’s why we often feel compelled to make a purchase after nibbling down a free sample of something small (olive oil, fudge… RELISH) at the local farmer’s market.

But if you’re in business, chances are you employ this strategy without even realising it – or at least you’ve been on the receiving end countless times.?

For example, consultants and agencies often use reciprocity by offering resources upfront, like a free audit or tailored advice in an initial meeting. This isn’t just goodwill. It’s a strategic approach that fosters a sense of obligation.

VIKKI’S QUICK TIP: Instead of starting with freebies, consider using reciprocity later in the relationship. After closing a deal, surprise your client with something extra – such as a bonus service, a quick follow-up report, or even a handwritten thankyou note. This unexpected gesture reinforces goodwill, making clients more likely to return or recommend you in the future.

2. Commitment and consistency: Start small, win big

Once someone commits to an idea, they want to stay with it. Because as humans, we all have a deep need to be seen as consistent.

Ever clicked ‘Yes’ on a poll? Suddenly, you’re in a sequence of emails asking for more information, leading you towards a sale.?

The same principle explains why charities remind you of your past generosity. ‘You’ve helped before – will you continue to make a difference?’ That little nudge taps into your need to align your current behaviour with your earlier actions, increasing the chances you’ll give again.

VIKKI’S QUICK TIP: In meetings, get your stakeholders to say ‘yes’ to something small – like trialling your idea on a small scale. The bigger yes will follow. Also, before sales appointments, get in the habit of ringing your prospect to confirm your meeting. This will increase the chances of them showing up because they’ve committed to it!

3. Social proof: Everyone’s doing it, so you should too

We trust the herd. If other people are raving about something, we assume it must be good.

Social proof is everywhere – from Google reviews and customer testimonials to ‘Best-Seller’ badges and ‘Most Popular’ package signposting in quotes and proposals.?

But also think about what goes through your mind when you walk past a packed restaurant – or a long queue for just about anything (like at a relish stall, for example).?You instantly want in, don’t you?

It’s also why buskers throw a stack of their own coins into their guitar cases before they even start playing!

VIKKI’S QUICK TIP: Encourage your clients and customers to be as specific as possible when giving feedback. ‘The service was great’ won’t cut it – people tune that out. But, ‘Our lead conversions doubled in 3 months thanks to their strategy’ packs a punch. The more precise the social proof, the more convincing it is.??

4. Authority: Expert-approved, so it must be legit

Ever been prescribed medication and not thought twice about it because your doctor recommended it? That’s authority in action. We trust doctors. Not because we understand the chemistry of every tablet, but because their credentials signal expertise.?

From doctors and police to CEOs and celebrities – certain professions, names and uniforms are powerful symbols of authority. And with that comes trust and influence.

It’s why, for years and years, cosmetics brands like L’Oréal?have dressed their actors in whitecoats in their commercials (with no mention of who these people are or what they do). The white coat alone is enough to signal trust and authority, leading viewers to assume the product has scientific backing.

Ever made an appointment at the Apple Genius Bar??

This concept exemplifies the authority principle by positioning its staff as trusted experts – even though they’re not qualified engineers or IT professionals.??

VIKKI’S QUICK TIP: Establish authority by sharing your credentials early in a pitch or presentation. A few subtle words (‘We’ve worked with companies like…’) will make people sit up and listen.

5. Liking: People say yes to people they like

This one’s simple: we’re more likely to say yes to people we like and feel connected to. So, what makes us like people? According to Cialdini, it comes down to one of these 6 reasons:

1. Physical attractiveness: People tend to view attractive individuals more favourably, assuming they’re more competent and trustworthy. (Sad, but true!)

2. Similarity: We’re more likely to like people who are similar to us in appearance, belief or interests.?

3. Compliments: Even when we suspect we’re being buttered up, receiving compliments makes us more inclined to like the person giving them.

4. Contact: The more we interact with someone, the more familiar and comfortable we feel with them.

5. Cooperation: When people work together toward a shared goal, it creates camaraderie and unity. ?

6. Association: We transfer the qualities of things or people we like to others by association. That’s why brands often partner with popular celebrities to transfer positive feelings from the star to the product.??

Think of the local barista who remembers your name and coffee order – welcoming you with a smile each time. You’re more likely to choose that café day in, day out… aren’t you?

And what about that client who loves chatting about shared hobbies or loves a laugh each time you catch up? Chances are they’re also the one that ends up extending your contract.

VIKKI’S QUICK TIP: Drop the formal jargon when it’s not needed. Let your personality shine in emails and pitches. People do business with people, not faceless corporations. Be yourself!

6. Scarcity: Get it before it’s gone

Nothing gets us ordering again like being told it’s the ‘last call’ at the pub – or ‘the kitchen is about to close’ at the restaurant.

And that’s because we all value things more when they’re rare or time-limited. It’s the old FOMO at play.?

‘Only 3 spots left for our masterclass’ or ‘Sale ends in 24 hours!’… you’ve definitely been on the receiving end of these tactics. Even sneaker drops with limited editions thrive on scarcity, turning what could’ve been ‘just shoes’ into a must-have item.

VIKKI’S QUICK TIP: Use scarcity in your emails and proposals – but only if it’s real. Nothing kills trust like fake urgency. For example, if you’re offering a client a discounted rate for early commitment, set a clear, reasonable deadline – like ‘This rate is valid until 31 October 2024’. Then be sure you don’t relent if they come back after the deadline expecting the same deal. Standing firm shows that your offer means something and builds trust, even if it’s uncomfortable in the moment.

7. Unity: We’re all in this together

This is the latest addition to Cialdini’s framework – and it’s all about shared identity.?

If people feel connected to a group or community, they’re more likely to trust and say yes to someone within it.

Politicians use this principle all the time. Think about campaign speeches that frame goals as collective achievements: ‘We need to work together to secure our future’. It’s no coincidence that this messaging builds unity. It makes people feel part of something bigger.

Similarly, Qantas taps into national pride with its Spirit of Australia slogan. It’s not just an airline. It’s part of the Australian identity, making customers feel that by flying with Qantas, they’re supporting something meaningful.

In copywriting, you often see this principle when brands say things like, ‘Join a community of marketers just like you’, building rapport through shared identity.

VIKKI’S QUICK TIP: Find common ground with your audience – whether it’s shared goals, values or challenges. In stakeholder meetings, use language like, ‘We all want the same thing…’ to foster a sense of unity and to build trust.

A FINAL THOUGHT: Yes, ethics matters

Cialdini’s principles aren’t about manipulation. They’re about understanding what makes people tick and building trust in ways that benefit both parties.?

But the key lies in how you apply them.?

If your intentions aren’t genuine – if you’re using these strategies to deceive or exploit – then it crosses into manipulation. And that’s where things go wrong.

Ethical influence only works when both sides stand to gain. In business, marketing or leadership, influence should empower others, not trick them.?

But when used with integrity? Applying these principles can build meaningful, long-term connections. And that’s the kind of influence that lasts.

Ready to equip your team with the tools to build lasting influence? Our Building Your Influence course dives deep into practical strategies that drive better decisions, stronger relationships and real business results.??

Looking to incorporate the psychology of influence in your brand’s messaging? Register for our public workshop, Dynamic Digital Writing.?