According to Cooper (2010), there is too little knowledge available regarding the link between general intelligence and physiological processes. The linkages between biological factors and intelligence seem to be much more important than linkages between learned capabilities and intelligence. The main factor of development of intelligence of an individual is considered a genetic inheritance. The influences of internal factors in the prenatal period differ strongly from the external factors, which include environment, its intensity and duration of exposure (Legg et al., 2007). The influence of biological factors is of an utmost importance to intelligence. Effects of behavior of parents on children are actually less important than it was previously thought, even though they are crucial for the development of character. A key role in the development of an individual still holds the family that educates and develops the mental functions as well as the whole personality (Nidditch, 2012), as the individual accepts level of language skills, communication methods, content roles, hierarchy of values or way of solving problems (Albe, 2008). This influence however forms the character rather than the intelligence.
There are many theories that vary one from one another in their focus, general postulations as well as other basic issues – and it is therefore hard to unite them into one universal theory. The most important factors can be divided according to the mental development in the following three groups:
Empiric theories consider the social environment as the main factor. These theories, regard the newborn as a “blank sheet” and therefore consider the environment as the key influence for formation and significance and the experience of learning. The main advocates are J. B. Watson and his pupil B. F.Skinner, a behaviorist and J. Locke, who created the tradition of empiricism (Cooper, 2010).
The nativist theory on the other hand, follows the philosophical nativism, according to which everything is innate to the child, which is born extremely capable, with high brain plasticity and must have the required space to grow and develop under favorable conditions. The most representative groups are called rationalists (Plomin,2005). According to A. Gesell’s theory, who formulated a law on child development, standards development, theories of alternating functional symmetry and asymmetry, the environment is therefore also important however for different reasons. The Theory of Interactions creates a compromise between environmental influences and biological influences on the development of individuals, which happens to be the interaction. Linear causality (the development of a child is subject to parental educational style) is alternated due to circular causality (as the child acts back to parents, so it affects). Convergence Theory formulated by W. Stern, which is part of this group of theories, view the child as an active organism which is modeled by social events.
Beyond this present division still stands the Stages Theory which looks at the child’s development as a continuous process of change, which can be divided into a variety of unique and dissimilar stages. Stages represent a logical progression in the development, where each step integrates with steps that have been achieved before (Rensing, 2009).
Culture is however crucial to psychology and development of intelligence in general, yet especially within the field of cultural psychology, which studies the intensity of psychological as well as behavioral tendencies, which are supposed to be embodied as well as rooted in culture. Cultural psychology considers the culture as well as the mind as inseparable (Heine, 2011). This school of thought can be also considered as mutually constitutive, due to the fact that people are to a certain extent shaped by cultural experiences they make. This particular school of psychology thus analyses the way the traditions and habits express as well as change and transform human psychology, leading to variances in unity of humans. According to the latest research, however, biology seems to have more importance over culture, as far as the impact on general intelligence is concerned (Cooper, 2010).