The human mind - a users guide - lateral thinking

Lateral thinking was developed as a set of tools to enable you to deliberately break out of the straight line, judgemental way of thinking that is the normal way that most people think. These tool move you to an exploratory model of thinking where you deliberately investigate the problem area, rather than just solving the problem.

This toolkit includes the following methods:

apc - alternatives, possibilities, choices
pmi - plus, minus, interesting
stepping stone

APC - alternatives, possibilities, choices

The basic idea of this tool is to be able to say in decision making and design "let's look for choices at this point". It is a flag you can use to get a brainstorming session going on that choice, before it is carved in stone and hard to change. Upon it's invocation, you deliberately start looking for alternatives, possibilities and choices that you would not necessarily think of in normal circumstances. Once you have generated these options, you can then apply the normal evaluation methods to your options, but with more options to choose from.


The escape tool involves deliberately dropping the solution to a problem, and looking to see if there are any other ways to achieve the same thing. This usually involves the changing of just one variable, to see what effects altering that answer has on the problem as a whole. While this doesn't always produce a solution, it usually leaves you with a better understanding of the problem.

PMI - plus, minus, interesting

This tool involves listing in order the plus, then minus, then interesting points about the current problem. This is an attention grabbing tool, and should be the first one that you use, as it sets the mood of objectivity and scanning that is necessary for using the other tools. It is also the right tool to use in a confrontational discussion, as the other parties will be sure that any exploration of the problem area will support their particular viewpoint.


The PO tool is a deliberate and provocative term that acts as a flag to change from the "that doesn't make sense, reject it" mode of thaught to the "that doesn't make sense, but how can it be applied to the current problem to improve the solution" mode of thought. In effect, it allows you to deliberately change the values of variables where "everyone knows that ..." to be a different answer, and see what that consequences are for this problem.

Stepping Stone

The stepping stone tool has you deliberately change one parameter of an object to see if it generates new ideas. There are a number of ways that it can do this:

Reversal - inverting the parameter
Exageration - change the scale of the parameter
Distortion - change the shape of the parameter
Wishfull Thinking - speculate on the ideal shape of the parameter
The Outragious - take the parameter to a rediculous extreme

You then look to see what the consequences of the change were, and see if they are usefull or interesting.

last modified 04:46 2003/08/14