Get ‘Em to Buy, Buy More, Buy Again: Six Weapons of Buyer Influence

How do people buy online?

Do they carefully define all their requirements, search for a seller and product that ticks all the boxes, then make a purchase?

That would be logical. But the majority of buyers don’t buy that way – even though they may believe they do. We are anything but rational in many aspects of our lives, and shopping is no different.

In this post, I set out the six behaviors hard-wired into our brains – actually programmed by evolution – that are immensely influential in buyer psychology. You can use them to be a much more effective seller.

Influence: The Psychology of Persuasion

In his book Influence: The Psychology of Persuasion, Robert Cialdini describes how six behaviours are used in marketing, to remarkable effect (it’s on and It sounds like hype, but this is no new marketing fad – Influence is a classic business book from thirty years ago. It has itself been profoundly influential on marketing in every industry and every part of the world.

Cialdini’s book has sold 2 million copies and been translated into twenty-six languages. So there’s your social proof! (Don’t worry – if you don’t get that now, you will later!)

The term “weapons of influence” is Cialdini’s, not mine, by the way. Although it’s a little sensational, it does capture the brute power they hold.

Influence What?

Influencing buyers sounds great, doesn’t it? But what do we want to influence them to do? That may sound like a naive question, but the answer is actually more nuanced than simply “to buy stuff”.

There are three objectives that online retailers typically focus on. Each can be measured and analyzed separately:

Broadly speaking, new sellers should concentrate on “converting” visitors into buyers before anything else. If you aren’t getting any orders, it’s a big jump to getting larger orders or multiple orders. Established sellers have more to play with, and might get a better return on their efforts by working on order value or customer loyalty.

Just a note: all this is relevant – in theory – whether you sell on marketplaces or through an independent store. But there is an important practical difference: there are fewer opportunities to influence marketplace buyers than direct buyers. Much (but not all) of the potential to influence marketplace buyers lies with the marketplace itself, as they “own” the relationship with the buyer.

The Weapons

Everywhere in the animal world there are instinctive responses – set sequences of behavior that occur in response to a specific trigger, such as birds’ mating dances. These behaviors are completely dependable: given the right trigger (or even a rough approximation of it) they always play out in exactly the same way.

Humans don’t have those kind of truly instinctive behaviors, but we do have something similar – the social norms that we all follow. Social norms are the “rules” that say what society expects of us. If you don’t follow them, you won’t be breaking any laws (on the whole) but your standing and acceptance in society could suffer.

The ultimate consequences of breaking social norms can be quite severe. When humans depended on their tribes for survival, good social practices could mean the difference between life and death. For example, sharing food with a hungry neighbor would compel them to share back when they have more than you – the norm of reciprocation. But if you break the norm, and refuse to share, when you are hungry they will feel less obliged to share back. Failure to reciprocate could quite literally lead to starvation.

So social norms are extremely powerful, and largely automatic. We don’t need to stop and consider if there is a norm at play, we just act. Like the animals, when presented with the right scenario, we respond immediately with a set behavior – a behavior programmed into our genes and reinforced by learning over thousands of years. If for some reason we act against a norm – either actively or by doing nothing – it feels unpleasant, uncomfortable, even stressful.

What’s all this got to do with selling online? Well, buyer psychology is human psychology, and sellers can create the conditions to encourage a normal social response. Is that ethical? I think so. As long as there is no trick or deception involved, all parties should get what they want.


Free Gift

Reciprocity is a powerful social norm. When people are given something, even if they didn’t ask for it, they feel strongly compelled to give something back in return.

It’s very widely used in marketing, most obviously in the giving of free gifts or samples. For example, charities send out unsolicited pens, stickers or even cash. They know the recipient’s safest course of action (psychologically speaking) is to reciprocate with a donation. Of course, there are people who receive a gift but don’t donate, but they tend to be those who recognize the manipulation. Even then, they often feel guilty or angry about it – there’s still an emotional response.

So, how can reciprocation be used in online retail? Here are some ideas:

Provide Helpful Content

There are many reasons for creating good, useful content that helps shoppers decide what to buy or make the most of a previous purchase.

But looking at it with reciprocation in mind may mean a slightly different approach. First, steer clear of salesmanship in the content itself – be as gracious and helpful as possible. Why? Because you want to appeal to social norms. If you are too forward with your commercial goals, you risk “flipping a switch” in their minds from a social relationship to a financial one. In a financial relationship, social norms go right by the wayside.

Second, once the “giving” is all done – the buyer has watched the video or read your blog post, for example – ask for something. You could show related products or ask for their email address, for example. When they should feel that they have benefited, absolutely ask for something in return.

Give a Free Gift

Free gifts and free samples are classic marketing techniques that take advantage of reciprocation.

Again, try not to make the business driver of the gift too apparent. Yes, logic would dictate that a business always has a commercial intention, but you’re not dealing with logic here. So, does a stress ball with a huge logo look like a genuine gift? Not really, the true intention is immediately obvious.

But something useful and related to your business, however small, makes a great gift. A tyre seller might include a free depth gauge with orders, or a florist could include chocolates. If you send an email after they have received their order (which included the gift) that’s the time to ask for what you want.

Leave Feedback

eBay sellers can leave feedback for buyers. They can only leave positive feedback, which feels a little odd – is it really feedback if it can only be positive?

Nevertheless, it creates an opportunity for reciprocation. You can leave feedback for the buyer, then send an email telling them:

  • They are a valued customer.
  • You want to thank them for buying from you.
  • You have given them good feedback.

After that you can ask, for example, for them to follow you on eBay or subscribe to your eBay Store newsletter (reference on and Beware of asking for feedback at that point, unless you time the email for after they have received the order.

There are automated tools available, both for leaving feedback and for sending follow-up emails.

Commitment and Consistency

Amazon Prime

People have a psychological need to be consistent with their past choices. Why is that? Well, imagine a world without consistency. A world where at every turn we re-examine the situation, and make a fresh decision based on the facts at that time. It would be wonderfully logical, but exhausting and paralyzing: we would hardly ever just get on with things.

Instead, we stick with our first choices most of the time. Sticking to our guns is seen as a sign of strong character, and it also avoids the anxiety of doubting what we have already decided – the commitments we have made.

Amazon’s Prime program uses commitment and consistency. Customers who sign up to Prime spend twice as much with Amazon as non-Prime customers. Are they logically evaluating each purchase they make, and deciding each time that they are better off buying from Amazon? I doubt it. Instead, their Prime subscription is a commitment to Amazon that makes future decisions straightforward – they just need to be consistent.

Here are some ideas for using commitment and consistency in online retail:

Run a Survey

Surveys are useful as research tools, but can also be used for marketing. For example, a survey could ask buyers to rate several different brands for quality, value and visual appeal. A few days later, a marketing email can be sent offering products from brands that they rated favorably.

It may sound a little far-fetched, but the survey answers actually function as small commitments. Multiple studies have shown that the act of expressing a preference or view makes people much more likely to agree to a larger related commitment when asked in the future. So if someone has already said they like the Gucci brand, they are simply being consistent with that by purchasing a Gucci product when the opportunity arises.

Run a Competition

Competitions can work well to build a following, and get followers to engage with you. Designed carefully they can also solicit a commitment, and drive consistent behavior in the future.

To form a commitment a competition should ask entrants to say (in some way) that they like your company or product – preferably in public. Before social media was widespread, you often saw slogan competitions where entrants completed a statement such as “I love product X because…” Today, asking for Facebook Likes or Twitter Follows is a common approach.

But slogan competitions are not used just to generate marketing ideas, and social media likes do more than build a following. Public commitments, even if small and insincere, are powerful tools of influence. Once one has been made, the door is open to ask for other consistent actions.

Don’t Fight Consistency

In the article Why You Should Stop Hankering… I looked at why some sellers should focus on marketplace trading rather than sell through their own online store.

But even when sellers trade through marketplaces and have their own store, they shouldn’t see an eBay or Amazon purchase as an open invitation to push the buyer to their own store. Why not? Because the buyer has shown their commitment to the marketplace, and their easiest course of action in the future is to do the same again – to be consistent.

Instead, offer the same incentives (as far as technically possible) to all buyers who purchase from you again, whichever channel they use. That way, you aren’t forcing an unwelcome decision on them and you increase your chances of a repeat purchase.

Social Proof


Social proof is a straightforward weapon of influence: we look at the actions of others to decide what we should do ourselves.

Following others doesn’t mean we are weak-willed. Like reciprocation and consistency, it’s a useful and generally reliable short cut for decision-making. If lots of people who are similar to you have purchased a particular product, then it’s probably a good choice for you too.

Reciprocation and consistency need a subtle two-stage process, but social proof can be much more overt. You see it in:

  • Statements about how many people have bought a product.
  • Positive customer reviews and testimonials.
  • Facebook plugins that show which of your friends like a particular page or product.

Despite being so obvious, social proof is very persuasive. Here are some ideas for use:

Show “Follower” Counts

All but the newest businesses have past customers, marketplace feedback, newsletter subscribers, social media followers or similar.

Wherever you sell products or otherwise promote your business, tell people how many others have already done what you are asking them to do. If you want them to buy a product, tell them how many have bought it before. If you want them to subscribe to your newsletter, tell them how many subscribers you already have.

Of course, the number has to be high enough to convey the impression that following the crowd is a great idea. If it’s not, the social proof may work in reverse.

Research shows that social proof has a much stronger effect if it features people who are similar to those you want to influence. So if you are selling products to teenagers, say how many teenagers buy from you.

Show Feedback

Marketplaces build feedback into their seller performance systems – it doesn’t require special technology or third-party services to collect genuine feedback, as it typically does with an independent store.

Show feedback comments in eBay listings to provide immediate social proof that you are a great seller.

Show What Other People Buy

Amazon is the master of using customer viewing and buying data to provide intelligent product suggestions. On its product detail pages alone you can see:

  • A suggested bundle with one or two other products.
  • Products also bought by customers who bought the product.
  • Products customers bought after they viewed the product.

If buyers can be helped to find the right product using information about what other people bought, they are more likely to make a purchase.

Automated product suggestion technology is out of reach for many online retailers. But if you know your products well and search your order database, you can add helpful suggestions of bundles, accessories or alternative products to your descriptions. Be sure to say that your suggestions are based on what customers buy, or it won’t be making use of social proof!


Liking smiling lady

Numerous experiments have shown that we respond more favorably to people we like. That’s interesting to know, but probably not a surprise.

Liking, however, is very personal and we often find it difficult to explain – so is there any way to use it in marketing? Well, it turns out that we are not as complex and unique with our liking as we might think. The following factors play a big part in whether we like someone:

  • Attractiveness
  • Similarity
  • Compliments
  • Familiarity

Celebrity endorsements are very common in advertising, even when the product advertised has no connection to the celebrity recommending it. This type of advertising uses the celebrity’s attractiveness and familiarity to create a mental association between them and the product being advertised. It’s not necessary to get people to like the product directly – just forming a connection with someone they already like is enough.

Here are some ideas for using liking in online retail:


Endorsements work on multiple levels, and the effect is strengthened if liking can be employed. Celebrity endorsements are great, but are out of reach for most sellers. Instead, add photos (flattering ones) to testimonials to leverage attractiveness, say what kind of business the endorser is in, and where they are based. If the buyer perceives an attractive person who is similar to them, the benefits of liking are much more likely to be triggered.

Tell Your Story

People like people, not faceless corporations. This is one area where small businesses have an advantage!

So tell the story of your business, including names and photos. Use a warm and friendly tone in your writing. Personally, I would advise against telling stories of overcoming illness or other calamity, as they tend to come across as insincere – even if they are true.

Use Your Personality

Every communication with a customer is an opportunity to build familiarity. So don’t send bland, formal emails when a purchase is made or order dispatched. Instead consider using a distinctive tone and signing off personally. Be consistent, and carry it through to marketing emails. Buyers will get to know you, connect your personality with your business, and like you.

Remember to be complimentary too – thank them for buying, and say it’s great to have them as a customer. Studies show that flattery works even if the praise is not accurate or if the recipient knows the flatterer has an ulterior motive.



Psychology experiments on the influence of authority are terrifying. Ordinary people taking part in well-known studies have administered apparently lethal electric shocks and used mental torture on those less fortunate.

What did it take to obtain such levels of compliance and sadism? Well, in the first experiment, it took little more than encouragement from someone in a lab coat. In the second, they handed out prison guard uniforms and performed mock arrests to set the scene. What did these experiments discover? That authority has a powerful compliance effect across all cultures and demographics.

The use of authority in marketing is much less sinister, but still effective. Authority figures can be seen from smiling nurses on cosmetic surgery sites, to earnest teachers on educational sites. They are generally models in suitable clothing and poses, but that doesn’t matter – the illustration of an authority works just as well as genuine authority.

How can online sellers use authority? Here are two ideas:


Endorsements from experts are invaluable. They don’t have to be from traditional professions or celebrities – although that’s great if it’s relevant and achievable.

Most sellers will need to think laterally. Is there a relevant trade magazine or blog that would be interested in reviewing you? Or an established businesses that is already a customer and might provide a quotation? A good photo, title and company name should be enough to establish their authority – even if most buyers have never heard of them before. If they are pictured in uniform or a shirt with the company logo, all the better.

Be An Expert

If you are an expert on your products – which to buy and how to use them – what could be better than being your own authority? You can’t endorse your own business directly, but you can use your knowledge to create helpful blog posts and videos.

Over time, you’ll build an impressive content database that can benefit your business in several ways:

  • Help customers select the right products for them.
  • Provide after-sales support with instructional content.
  • Increase your visibility on search engines and social media.
  • Demonstrate expertise and establish yourself as an authority.

A great example of this is the The Shower Doctor, with their YouTube channel of useful shower repair videos.


Limited Time Offer

The last weapon of influence is the most obviously connected to our prehistoric past, when we were frequently on the fringes of survival. Scarcity is simple: when something is in short supply we want it all the more.

There is a primal logic to the appeal of scarcity. If there’s not much of something there may soon be none, so we better get it quick or risk suffering without it. It’s used routinely in offer deadlines, items remaining counts, daily deals and more. Scarcity is extremely persuasive and often plays a part in the addictive feeling of “getting a bargain”.

Scarcity is easily manipulated, but I don’t advocate deceptive practices for any business. Instead, demonstrate or create genuine scarcity – here are some ideas:

Show Evidence of Scarcity

When stock is running low, say how many are left. If there are plenty left, follow Amazon’s lead and just say it’s “in stock”. In a similar vein, but connected to social proof instead, you can also say how many have already been sold – if it’s a lot.

eBay have an interesting tactic that combines scarcity and social proof: how many people are viewing the product. It helps demonstrate popularity (social proof) and also creates a feeling of urgency (scarcity). Again, it only works if it’s a big number!

Use Limited Offers

Temporary price-cuts, limited bundles or special editions, flash sales, free gifts “while stocks last” and other limited offers can be very effective. Make sure you tell buyers that the opportunity will not last forever, and provide an explanation or evidence that it’s a genuine limit – some will be skeptical.

In Closing

There’s a lot that sellers should do to satisfy buyers, but there’s a difference between meeting buyers’ expectations, and really influencing them to do something you want.

Cialdini’s “weapons of influence” work on a subconscious level and are very powerful. People are compelled by social norms and our evolutionary heritage to respond in a set way to them. In summary:

  1. Reciprocation means that when people are given something they feel compelled to give something back.
  2. People have a psychological need for consistency with their past choices – their commitments.
  3. Social proof means we look at the actions of others to decide what we should do ourselves.
  4. Liking means we respond more favorably to people we think are attractive, similar to ourselves, who compliment us, or who are familiar to us.
  5. Authority has a powerful compliance effect across all cultures and demographics.
  6. Scarcity means that when something is in short supply we want it all the more.

Do you use any of these tools in your business? Do you plan to? I’d love to hear what you think in the comments below!



HaHa, great psychology but I actually doubt many readers will really understand the subleties of what this article contains.

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