Posted by: aphr | November 17, 2009

Influencing Decisions

attraction and compromise

attraction and compromise

Often when we choose between two alternatives, we actually choose which criterium to value more. For example let us compare usb drives. We might agree that they should be as small as possible, but also have as much storage capacity as possible. Now if we compare two drives A and B. A is large and has a lot of storage, B is smaller, but has less storage. We have to decide, do we want the larger drive with more storage or the smaller drive with less storage?

Of corse this decision can be obvious for some. Many customers might  not care about size, but rather about price etc. But let us assume for a moment that we have a customer who thinks just about these criteria and is not sure which to pick.

If we want them to pick the small drive B, we can propose a third drive C that is even smaller and has even less storage room than B. They will then be very likely to ultimately pick B as a compromise. We could also influence their decision in that direction by offering a drive D that is inferior to B in both categories, while it is not inferior to A in size. That is, D would be of a size between A and B, but have even less storage than B does. They will then be very likely to pick B by the rule of attraction.

Of corse by symmetry one can find C* or D* that promote A just the same.

A possible explanation is that people do not always evaluate two possibilities via some kind of utility function but rather count arguments towards one and towards the other. “B is better than D in all regards” counts as an argument for B, just like “B is the compromise” does. Influencing people might be  like a pro-con-game where you never have to invalidate the cons, but just give a huge quantity of credible pro arguments.

More on  changing minds can be found here:





  1. This site seems to be a little bit evil. I like this.

  2. Hi,

    I must admit that I am very happy to see a new post. Keep checking your RSS feed for quite a while with no updates. Keep the good work up and I will keep the RSS feed in my bookmarks.

    Have a nice day.


    • Hey… a reader who is not a close real-life friend. How did that happen 🙂 Me likes it.

      • Hey,

        actually i’m into the productivity thing. Found this nice blog while searching the web for 80-20 principle and David Allen’s Getting things down.

        First, I checked who the author of this blog is. Found out that you are a PHD student at the TUD (my respect for that). I was attending the TUD as well, but left withour my PHD.

        Second, it is obvious with such a -strong- connection to save the feed 😉

        Your posts were smart and interesting => hit the bookmark button


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