# Computational Characterization of Activities and Learners in a Learning System
## 2 Background
### Learner Model  
A learner model is a compact definition of the features that characterize the individual as a learner. In this section, some of the main theories that attempt to characterize individuals as learners are presented. The fact that each person has different skills and learns differently seems to be confirmed by different authors [12,13]. Among all the factors that affect the academic performance of a student, some authors consider that the individual characteristics of the person (intelligence, learning style, motivation, character, etc.) are the most important factor [14, 15, 16, 17]. Thus, the intellectual capacity and motivation of the individual account for up to 50% of his/her performance, compared with factors that are considered to be external [16]. When designing a learning process, therefore, it is important to be aware that within the same group, there will be students with different learning styles, distinct types of intelligence and diverse motivations [18,19]. The so-called learning styles refer to a set of theories and methods defined in the literature that propose the classification of students according to the way they learn. Although there are many theories and they are very diverse, there are also many criticisms on this subject. The scientific basis of these theories has been widely criticized, in the sense that they often consider styles as separate compartments. However, learning implies the personal construction of learning strategiesinvolving all our senses and a very diverse set of skills and abilities, and the effectiveness of most learning style models is not supported by sufficient evidence. In spite of these criticisms and without evaluating them, it is interesting to review some of the most renowned theories in order to try to understand the learning processes that students develop, and to try to characterize them. One of the best known theories is that of [PERSON]'s multiple intelligences [18; 20]. This theory considers eight intelligences that imply different ways of learning: linguistic, logical-mathematical, visual-spatial, musical, bodily-kinesthetic, interpersonal, intrapersonal and naturalistic. The triarchic theory of intelligence [19] also classifies intelligence, in this case into three subtypes: componential (mental mechanisms), experimental (relations between the individuals and their experience) and contextual (how the componential processes are put into practice). The VARK model of [PERSON] [21] categorizes the experiences of the students and teachers during learning into four overlapping sensory modalities: visual (the information is preferentially represented as maps, charts or symbols), aural (heard or spoken information is preferred), read/write (information represented by text is preferred) or kinesthetic (a preference of practical elements such as demonstrations, simulations or case studies). There are other theories that aim to classify the learning style of students in the form of inventories. This is the case of [PERSON]'s Learning Styles Inventory [22] (comprising four learner styles, namely, social learners, independent learners, conceptual learners and applied learners) and the Approaches and Study Skills Inventory for Students [23] (three possible approaches to learning, namely, deep approach, strategic approach and surface approach). It is also the case of the Kolb Learning Style Inventory [24], with four identified styles, i.e., diverging, assimilating, converging and accommodating. An extension of this theory is the new Kolb Learning Style Inventory 4.0 [25], which is one of the theories considered in the definition of our model. It defines nine styles, i.e., initiating, experiencing, creating, reflecting, analyzing, thinking, deciding, acting and balancing. All the presented inventories collect the information about the learning styles through self-reported questionnaires that evaluate the attitudes of the students about learning and studying. Learning styles are not the only internal factor that can affect learning.