What I find really cool about behavioural styles, people styles, social styles or call them what you will. is the fact that you can measure it on just two dimensions of behaviour. The horizontal arrow denotes Assertiveness, which is the degree to which a person will try to influence others. So someone to the left of the vertical arrow will influence by asking and the person to the right, by telling. The vertical line denotes Responsiveness, which is the degree to which a person responds to another emotionally. So a person above the horizontal line would appear to be "cooler" and have their emotions in check, whereas someone below the line would be "warmer" and perceived as more people oriented. By observing behaviour on these two dimensions you come up with the 4 styles. If you would like to find out more, post a comment and I will do a bit more on it. I find it fascinating and, if you know what you know then you can modify your behaviour to accommodate others to have a more productive and rewarding interaction with them!