Imagine walking into a library. All objects in that building are based on the same principle, they all use paper with letters printed on it to deliver a specific message. So should we just put all the books, articles and newspapers on one pile? No – it makes sense to structure the objects according to the topic they deal with (so that books and newspapers about gardening stand close to each other). This additional information helps us to deal with the information presented in a much more efficient way. The same is true for the categorization of automatic processes into meaningful groups.
The model of Strack and Deutsch proposes different levels of the reflective system, like propositional categorization or Noetic decision. The Impulsive system is composed of episodic and semantic links, which they call the “associative store”. It is within this associative store that through perception certain concepts are activated and activation spreads to behaviour schemata, that in turn may be acted upon. These impulsive actions are important, because only they can produce behaviour.
A scientific model is always a simplification of reality. Models that can explain everything are indeed worthless to science. The question then becomes: What is the ultimate goal of our research into behaviour? Do we want to end up with a system that explains behaviour in purely mechanical (biological, chemical, and physical) terms, as sometimes suggested by neuroscience? If that is the case, then we should try to incorporate all automatic effects into one big theory. Yet within such a model it would be hard to generate specific hypotheses to investigate. Taking a smaller concept (such as goals) it is much easier to identify specific automatic behaviour that is connected to it (such as goal activation). The description of the automatic process at hand can therefore be optimized to the specific situation (for example how different goals might interact), which makes it easier to focus on the relevant facts. The hypothesis as proposed by the duality model of Deutsch and Strack can be tested on the theories about automatic effects. Incorporating new knowledge about the processes within the impulsive system can improve those theories, but does not mean we have to take everything into account at the same time.