The word prejudice is used in most cases to show the idea or assessment that one has of someone, but in a hasty or anticipated way, in short, it is the opinion that one has of something or someone in particular before time, without even being certain about it.
Preconceptions, in general, come with criticisms (positive or negative) about a subject or situation, without having all the necessary prior data to do so. It is very easy for people to get carried away by appearances and judge in advance, without really knowing if what they think is true or not. For example, young people who have tattoos have always given the impression that they are criminals or vagrants, however, an idea is being created, of these people, that is probably wrong. In this sense, a prejudice is forming that is closely linked to discriminatory behavior, which could lead to unhealthy consequences.
It can be said then that, when the prejudice that one has of a person is extremely negative, he or she will be more prone to rejection, even when there is not enough data to do so.
On the other hand, in the field of pedagogy, this term is defined as the image or idea that a student may have about some element of reality and that represents the beginning of a teaching stage for the use of true concepts.
With respect to science, it considers preconceptions as the imperative tendency of the scientist to make affirmations of prior knowledge on a specific topic, thereby helping to sustain the dominant ideas.