The goal of sales is to sell something to someone. You need someone to say “yes” to what you’re offering.

There are many techniques you can use to increase your chance of getting a “yes”.

One of my favourites is the psychology of persuasion.

Previously we covered three of psychologist Robert Cialdini’s (the father of the psychology of persuasion) six principles of persuasion – reciprocity, scarcity, and authority.

Let’s have a look at the final three – consistency, liking, and social proof – and how you can use each (ethically of course!) to close more sales.

1. Consistency

Humans like consistency. We like our current behaviour to be consistent with things we’ve said in the past or previous actions we’ve taken.

How does this work in real life?

Cialdini provides an excellent illustration from a series of studies where everyone in a suburb was asked if they would put up a giant billboard on their lawn to promote a Drive Safely campaign. Very few said yes – which isn’t much of a surprise!

In another similar suburb, four times more people agreed to put up the billboard on their property.

What caused the difference? The residents of the second suburb had been asked a week and a half previously to place a small postcard-sized message in their window to show their support for the Drive Safely campaign.

The small initial commitment led to the larger commitment because of the consistency between the two. The second group of residents already viewed themselves as supporters of the Drive Safely campaign, so when they were asked about the billboard, they were much more likely to say yes because it was consistent with this view.

How does this work in sales?

You can actually use it throughout your sales process. With every step your prospect goes through, reinforcing their behaviour.

Your prospect has a problem, so get them to articulate it as part of your discovery session.

When you demonstrate your solution, ask your prospect if you think it will solve their problem. Them saying, “yes, your product xyz will solve my problem abc,” is making a commitment.

It’s a small commitment and easy for a prospect to give.

Then, when you move on to the close – it’s pretty hard for your prospect to not say “yes” because they’ve already made the verbal commitment, and purchasing your solution is consistent with this previous action.

The principle of consistency is also commonly used in marketing where a company, when you visit their website, will offer free information, such as a downloadable guide or ebook (called a lead magnet), in exchange for your email address.

A relatively easy thing to do, and you’ve now demonstrated that you’re interested in the company, their industry, and the type of information and solutions they offer.

When they offer you something more significant, such as signing up for a training programme or purchasing one of their products or services, you’re much more likely to say yes – compared to if they’d tried to sell to you straight away.

You may have noticed the principle of reciprocity is also at play with the lead magnet as well!

Have a look at your sales process and see where you can encourage psychology consistency. Cialdini recommends that the small actions or commitments are active and voluntary. For greatest effect, they’re also public and in writing.

2. Liking

Most people, myself included, agree with this sentiment – I prefer to do business with people I like.

If someone you like asks you do something, you’re much more likely to say “yes”.

This principle of persuasion is really as simple as that!

However, you don’t just leave it up to chance. You can influence whether people like you or not.

Cialdini identified three factors that make people like each other – similarity, compliments, and cooperation towards mutual goals.

This is where building relationships with your prospects is so important.

When you take the time to get to know your prospect, you’ll identify what you have in common and you’ll see where you can genuinely compliment them. Importantly, you’ll be able to set your sales process up as a way to achieve a mutual goal – providing a solution for their problem.

The impact on your sales closure rate can be pretty dramatic.

A study looking at the impact of different factors on negotiation shows the power of the principle of liking.

A group of MBA students from two top US business schools were told, “Time is money. Get straight down to business.” The result was only 55% of the students could negotiate an agreement.

Another group was asked to exchange personal information and work out something they had in common with the other psychology person before they started negotiating. 90% of the students successfully negotiated an agreement. Not only that, but the outcome was also about 18% better for both people.

Get to know your prospects!

3. Social Proof

How do you choose between two restaurants you’ve never been to but appear pretty similar?

The same type of food. Similar décor. Friendly looking staff. The only difference is one restaurant is almost full and the other only has a few patrons.

Almost everyone would pick the restaurant with the most people.

Why? The principle of social proof. When we don’t have enough information about something, we look at what other people are doing to help us make a decision.

There are many ways you can use social proof in sales.

The most obvious is using testimonials from happy customers and clients.

Case studies on people with a similar type of company and problem as your prospect can also be very effective to help them decide to say “yes” to your solution.

Statistics, awards or recognition that show how many people use your company’s products or services are another way to use social proof.

At the close, if you have multiple packages, you might point out which the most popular one is to help your prospect make a decision and get them across the line.


Using the psychology of persuasion can dramatically increase your chance of making a sale.

Consistency can help you persuade your prospects to say “yes” to your full solution by getting a commitment to something smaller first. Building relationships with and getting to know your prospect first, before diving into the sale, enables you to use the principle of liking to increase your chance of a “yes”.

While social proof is an psychology effective way to use your current and past clients to convince new prospects to choose your products or services.

We work with business owners and salespeople to help them attain and close more sales. Get in touch to find out more about our sales training and coaching programs. Get in touch

Sharn Piper – CEO
M: +64 27 733 4333