Biological functions of the brain are important to touch on, because talking about cognition and cognitive functions is relatively unexciting without knowledge of the way the brain works. So much more is known about the brain today that validates theories of cognition.

 Developmental Systems Approach suggests that development occurs as a function of the interaction of multiple layers of an organism and its environment.  Epigenesis suggests that a human, at any given developmental level, will be qualitatively different—both in terms of structure (what they look like/what they know) and function (what they can do). These changes occur at all levels of an organism because of bi-directional relationships with all of these levels.

Genetic activity (DNA RNA proteins) structural maturation function, activity  The emergence of new structures and functions during the course of development.  Development is characterized by an increase of complexity of organization.  Reflects a biderectional relationship between between all levels of biological and experiential variables, such that genetic activity both influences and is influenced structural maturation, which is bidirectionally related to function and activity.

 Environment  Behavior  Neural Activity  Genetic Activity

 Genes direct biochemical production (proteins, for example).  Bio-chemicals determine structural development (like various tissues—nerves, muscles, bones).  Use or disuse of these structures (nerve cells or muscle cells, for example) can turn on or off genes—which in turn can create or allow to atrophy nerve or muscle cells.

 There are no simple genetic or experiential causes of behavior. Instead, the two interact to increase or decrease the probability of behavior based on the interaction of genetic predisposition and experience.  But, remember… experience is not just experience generically defined. Rather it is species-typical environmental experience— both prenatally and postnatally.

 Critical periods are the time in development when infants/children are “ripe” for the influence of environmental experiences. (when a specific skill or ability is most easily acquired)  Humans are prepared neurologically for certain experiences and not others. When the time is right, the experiences exert their most effective and efficient effect on development.

 Neurological preparedness suggests that there are undifferentiated neurons that become specialized for various functions as a result of their location in the brain and experience. When these neurons are made available for differentiation, the nature of experience can and will have a clear affect on them, and hence all of development.

 Behavior Genetics — studies genetic effects on behavior and complex psychological characteristics, such as intelligence and personality.  So, is biology truly destiny?  No… remember, all genetic effects are moderated by environmental effects.

 A person’s genetic makeup influences which environments one encounters and the type of experiences one has.  Genes drive experience and determine how we organize our world and how our experiences are perceived.

Child’s Genotype Environment sought out and established by the Child Child’s Phenotype

Rearing Environment of the Child Phenotype of the Child Genotype of the Child Genotype of the Parents

Therefore, characteristics of the child, as well as the rearing environment and genetic contributions of the parents, influence the course of development.

 Passive Genotype — The environmental influences parents provide for their kids exert a gradually decreasing effect on the children as the children get older.  Environmental effects decrease with age.

 Evoactive Genotype — Temporamental characteristics of children that elicit responses from others.  Environmental effects remain constant with age.

 Active Genotype — As children get older, they have more and more ability to select environments that suit their own particular needs.  Environmental effects increase with age.