Of what I undertood by the greek epicureans the instincts as faculties that are programmed in us by Nature, and as our specie is evolved to survive are : the feelings of pain and pleasure along with the senses. From the day we are born the anticipations or preconceptions are connected with the concepts of the words on things, and more complex concepts - always based on materialistic reality e.g justice, as well as they all are measured by the senses and the feelings in accordance with the experience of the reality. And in the duration we are learning our words of our language, the mind is making an image of every thing we have learned. So, we keep in our minds as a memory the concepts of all the words of the things, and issues, to be in our mind as pre-conceptions. All these are accordance with the reality and our experiences (always measured by the senses and feelings), and in the duration we are speaking the mind picks all these up. The problem that comes out is when the preconceptions are based on true or false. The preconceptions will be false if they contradicted by the phenomena of the reality, and they had not be measured by the senses and the feelings. And they will be true if are proved by the phenomena of the reality measured by the senses and the feelings.
IMO on the issue of preconceptions goes the talent too e.g. if someone can play a piano or be able to learn many languages. This goes to the neurones (cells) of the mind, that are genetically formed in such a way (synapses) by heritage of the genes. But even the man that has any talent has to practice his talent to be more talented. Epicurus had had the talent to observe the Nature carefully, but also had had all the written works from his ancestors as philosophers. In the duration of his life and with the help of his friends, he managed to clean them up from confusion, Myths and all these things that were, and still are against the reality of the phenomena, and our goal of pleasure. His way of thinking is called "manifold way" that is based on probabilities of the phenomena searching out the causes that caused them. His "swerve" of the atoms is based on his observation that in Nature there is not only a cause with a result, as Democritus and others claimed, but in Nature there are many causes and many results, since the three factors that are created all the things are and the need, and chance and the swerve (as our free will). For the Canon and the analogy we can read many things in the book by Philodemus "on signs".