Answer:
A concrete thinker is one who, in his mental construction, does not contemplate or does not give importance to the context of the situation or thing on which his thought falls. Thus, these people focus only on the central concept of a situation or thing, without taking into account that it can be modified by their environment, which leads to errors in judgment.
In order to help these types of people in the classroom, there are two fundamental techniques: 1) give the student a broad concept, encompassing both context and events or things in particular (an example may be to encompass an ecosystem, instead of a particular group of species), and 2) schematize concepts in such a way that they interrelate with each other, being impossible to interpret in a particular way.