While designing any product or service, a combination of knowledge in the head and knowledge in the world is essential.
Knowledge in the head is nothing but the knowledge stored in our mind: memories. Knowledge of the world is the information that we gain on interacting with a product or service that is completely or partially new to us. Sometimes, we apply what we know to what we see and that is a combination of our knowledge in our mind and in the environment around us.
Knowledge in the world is usually designed around mapping and operation of a product. The feedback that we receive on using these products is what we learn and usually remember the next time we interact with that particular product.
For example, a year back I tried my hands on the guitar. I had no idea how do the mechanics of a guitar work; it was basically alien to me. Therefore I began to explore the instrument on my own, experimented by trying simple tunes, pulling on strings and getting a gist of the instrument as a whole. The operations of the guitar were in itself self-explanatory. Whereas the sound it made help me gain a knowledge of whether it sounded melodious or harsh to my ears. Furthermore, I skimmed through the mini tutorial book that accompanied the instrument which helped me upgrade my skills. Thus, I was using a 'knowledge how' that I gained from the knowledge present in the world of music. As Norman states, a skilled musician would make use of 'procedural knowledge' and this is gained best through demonstration and practice; and this is exactly what I experienced and carried out.
An example of knowledge in the head for me would be 'Fear'. We have encounters with our fear through experiences and one such incident introduced me to my fear of high speed. Back in 2015, I had a terrible accident when a car knocked me down and I suffered a serious brain injury. It was just another day, I was rushing to college on my scooter (scooters are very common and popular amongst people in India) and just 100 meters ahead of my house a sedan drove super fast at a blind turn and bumped into my scooter. I was flung 5 feet high in the air and landed badly on my head. Luckily, I survived.
From that day on, I have been scared of high speed, blind turns and riding scooters. I learnt from a bad experience and thus understood while using a car later on that my mind and body cannot take high speed after a certain limit. The good lesson that I, unfortunately, learnt the hard way was to always be extra careful at blind turns and always wear a helmet no matter how close or far your destination is.
After this particular incident, I never had to specifically instruct myself to mind my speed or slow down at intersections. It automatically happens as that knowledge, driven by my fear, is securely stored in my head.
Talking about knowledge in the head + world, I have experienced it best during my interaction with the iPhone 7 plus.
I had previously used the iPhone 5s for around three years. Therefore, I was completely accustomed to the mechanics of that phone, the navigation and the features that the model offered. For me, jumping from 5s to directly a 7 plus was a big upgrade. But, being an apple user for long- I did not have issues getting used to the new phone except for a few new features like 3d touch, enhanced camera features and so on. Thus, I used the knowledge in my head that I gained through my experience with the iPhone 5s and learnt more about the updated phone through the level signifiers and discoverability that it offered. The natural mapping of the phone helped me to navigate better without having to use any knowledge of my own.
Thus, we observe that knowledge in the head and the world exists not only while using products but also in our day to day experiences and encounters.
Knowledge and Design