A mental model is the shape of an idea in your mind and how that idea is connected to other ideas to form a huge interconnected cognitive spiderweb. Everything that you know is a mental model, from Ducks to Dentists or from hiccups to happiness.
Not total Recall
We are qicker to find mental models that we use often, whilst mental models we don't use fade over time so as they appear less relevent to us, getting out of the way to allow more recent models to be found more quckly.
Models as metaphors
Sometimes we can use mental models that we
Ideas about ideas
For example, if I was to say the word "Banana" to you would probably start thinking of that bright yellow Banana colour, and an idea of the curved shape. This mental model will likely connected to other concepts in your mind, perhaps you will think of the idea of fruit and healthy eating, or perhaps monkeys who are often spoken about in relation to bananas. If you often think about, or encounter the idea of healthy eating, the connection to healthy eating might be stronger, but if you frequent watch a cartoon featuring a monkey who eats bananas the monkey connection might be stronger. You will likely know things about Bannans that you wont think of right away, as they are less comoncs to you then
The image of the world around us, which we carry in our head, is just a model. Nobody in his head imagines all the world, government or country. He has only selected concepts, and relationships between them, and uses those to represent the real system