Book notes: Influence

Jun 9, 2016

For my third Blinkist book summary, I chose Influence by Robert B. Cialdini.

I bought this book on Kindle about 4 years ago but only read the first three chapters. I've always wanted to finish it and this was a good opportunity to see what else was in the book.

Opening examples

Interesting opening example of female turkeys which, upon hearing a "cheap-cheap" sound, will automatically assume that the thing making it is their child. Even if it's actually a polecat with a tape recorder strapped to it. It's meant to illustrate that all animals have certain shortcut behaviours and humans are no exception.

The next example is when a gem-store owner accidentally doubled the price of some jade rather than halving it. It quickly sold out. It's meant to highlight the fact that humans have the shortcut of: "price indicates quality". It was the same jewellery but people assumed it was better because it cost more.

The rule of reciprocation

We feel like we have a duty to repay others in kind for what they have given us. If we do not repay a favour, it can feel like a psychological burden.

To rid ourselves of this perceived debt, we are often willing to reciprocate with a much larger favour than the one originally received.

To exploit this, you can offer a smaller favour and then ask for a larger favour in return.

To protect against this, you can learn to recognise when a favour is genuine and when it is being used as an abusive tactic against you. In the latter case, you can simply refuse to fall for it.

Of course, you can also use this in a friendly manner. You can do something for someone which is easy for you to do but is worth a lot to them.

The best example I can think of is to give honest and constructive feedback on something they have been working on. It only costs you a little bit of time but can be incredibly valuable to them.

Similarly for knowledge sharing. If you know a lot more about one subject than someone else then you can give them advice or fix their problems more quickly than they could. They can then repay you by sharing something they know but you don't.


  1. Ask for something pretty big
  2. They say no
  3. Ask for something smaller
  4. They say yes

This can be even more effective than just asking for the smaller thing first. It works because when you lower your request, you are making a concession to them. They feel obliged to reciprocate by making a similar concession and accepting your second request.

Additionally, the principle of contrast will make your second request seem smaller/easier in comparison.

As an added bonus, they might even say yes to your first request.


People hate losing opportunities. If an opportunity is seen as limited in availability then it will be viewed as more valuable in comparison.

If information about the opportunity is limited then it can trigger the effect too.

It can be more effective when availability suddenly drops rather than when it has been low all along. Also if you think you are competing with others for the same limited resources.

To protect against this, you should ask yourself if you really want the thing for what it is or if you suddenly have an irrational desire to possess it. The latter case is often triggered by artificial scarcity.

I recently visited to book a hotel and I noticed that they are playing this strategy to a ridiculous degree. Everywhere on their site they are trying to suggest that the hotel your are looking at is about to get booked up.

They tell you how many times other people have booked that hotel today and how many rooms are left. They aren't even remotely subtle about it either. They show search results saying things like: "You missed it! We have reserved our last available room at this property." The most annoying part is that even though I knew exactly what they were doing, I still felt like I was getting strongly influenced by it.

Banned things are more desirable

Again, humans hate losing opportunities so when something is banned, it can be seen as more desirable.

I suspect that the competition aspect is especially powerful here. If something is banned then other people might be less willing to take the risks to acquire it. But if you can get it and they don't, you might have an advantage over them.


We have a strong desire to appear consistent in our words and actions.

If you commit to doing something or openly state your opinion then you will be less likely to go back on it later.

The effect can be made even stronger if:

  1. Your commitment is public
  2. Your commitment is in writing

Sales people can exploit this by getting you to commit to changing your self-image and then selling you something that is consistent with your new self-image.

It also reminds me of a failure mode in group-brainstorming. If members of the group suggest solutions before fully exploring and understanding the problem then they may be more likely to stick to those solutions in the long run. It can be much better to avoid proposing solutions until you have discussed the problem in depth.

Making a choice to fight for something

When you choose to fight for something, it changes you. When you acquire something after fighting for it, you often value it more.

If it is possible to justify your actions with an alternative hypothesis then it can weaken the effect.

This can be exploited by making an initial low offer and giving time for someone to get accustomed to buying the thing. Then, once they have already decided they are going to get it, the price can be increased or additional extras can be added on. They have already decided to fight for the thing and so the additional extras don't seem like such a big deal.

Inner change can often be much more effective than external pressure.

When uncertain, we look for social proof

When we don't know what to do or think, we will look at others around us.

A negative example of this can be the "bystander inaction effect" when something negative is happening but nobody helps. The effect can be mitigated by singling out a specific person and asking for their help/action.

We like to emulate similar people

Observing people similar to us can greatly affect our choices. Fashion choices being the most obvious example.

Advertisers can exploit this by staging fake interviews to make it seem like people similar to us use their product.

We comply with people we like

Many factors contribute to who you like:

  1. Physical attractiveness (causing a halo-effect where we assume they are more talented in other areas)
  2. Flattery/complements (but obviously this can be over-done)
  3. Similarity (and finding common interests/circumstances)
  4. Co-operating with someone (aka being on the "same team")
  5. Positive associations (could be anything related to the person)

Also, I think there is a lot you can do to build genuine trust and friendship which isn't mentioned in the summary. Probably because that's not a tactic most salespeople could use.

To protect against this, ask yourself if you have come to like someone in an unusually short amount of time. If so, they may be deliberately manipulating you.


We can be influenced by real authority as well as just symbols of authority.

People can masquerade as authority figures using symbols like titles and clothing.

Also, real authority figures can sometimes have agendas of their own and be trying to manipulate you.