Both genetic and epigenetic factors interact with environmental variables to shape out level of health
and well-being across the lifespan.
Our body cells’ nuclei contain 23 pairs of chromosomes that are made up of about, an astounding 2
metres of finely coiled DNA molecules. Each chromosome is divided into segments, called genes, each of
which influences a particular feature or developmental pattern. A gene controlling a specific
characteristic always appears in the same place (the locus) on the same chromosome in every individual
of the same species. For example, the locus of the gene that determines whether a person’s blood type
is A, B, or O is on chromosome 9.
Each of our 46 chromosomes contains anywhere from 231 to 3141 genes. In all, each human body cell
nucleus possesses an estimated 23 000 genes.
An essential function of genes is to instruct body cells to combine 20 standard amino acids to build the
35 000 or so proteins that our bodies need to function properly.
Basic structural elements of our bodies—muscle, brain, and bone—are made up of different proteins.
3 principles of genetic transmission explain such patterns of inheritance:
1- dominant and recessive genes
2- polygenic and multifactorial inheritance
3- mitochondrial inheritance
Height is a multifactorial inheritance, it’s affected by both genes and the environment
Some preliminary evidence shows that acquired epigenetic traits linked to chromosome structure
alterations may be inherited in humans.
3- behavior genetics
5- evolutionary psychology
6- evolutionary developmental psychology
7- evolutionary prenatal programming and adult health and disease
(if the eventual mature environment, whether adequate or deprived, matches the prediction, then the
risk of metabolic disease in later life is low. If there is a mismatch between the predicted and actual
mature environments, particularly if the mature environment is richer than anticipated, then the risk of
metabolic disease is enhanced.
Advances in human genomics will likely play a vital role in predicting and preventing diseases in the 21
century. Newly discovered epigenetic factors may prove to be the proverbial “missing link” that helps us explain
how nurture interacts with nature.
Evolutionary theory and research are making scientists more aware of the relative importance of early-
life events in making accurate predictive-adaptive responses that match expected future environments.
Emphasis on the formative role of early experience is a hallmark of psychoanalytic theories. An
inadequate early environment will result in fixation, characterized by behaviors that reflect unresolved
problems and unmet needs.
1- Frued’s psychosexual theory
2- Erikson’s psychosocial theory
Erikson claimed that development results from the interaction between internal drives and cultural
demands. He believed that development continued throughout the entire lifespan. In his view, to
achieve a healthy personality, an individual must successfully resolve a psychosocial crisis at each of the
8 stages of development.
Childhood crises set the stage for those of adolescence and adulthood
The humanistic theories share Jen-Jacques Rousseau’s basic premise of innate goodness, and they begin
with the optimistic assumption that the most important internal drive is each individual’s motivation to
achieve his or her full potential.
Maslow’s greatest interest was in the development of motives, or needs, which he divided into 2
subsets: deficiency motives and being motives. The first involves drives to maintain physical or
emotional inner balance (homeostatis).—eating, drinking, etc. being motives involve the desire to
understand, to give to others, and to grow—to achieve self-actualization.
In carl roger’s view, it’s never too late to overcome early conditioning or the residue of unresolved
dilemmas. He believed people have the potential and motivation to try to do just that—a concept
known as personal growth.
Positive reinforcement entails adding a consequence that follows a behavior and increases the chances
that the behavior will occur again. Negative reinforcement entails taking away of a condition (usually
something unpleasant) following a behavior and increases the chances that the behavior will occur
Negative punishment entails taking away a condition (usually something pleasant) that follows a
behavior and decreases the chances that the behavior will occur again. Can result in extinction. Positive
punishments entail adding a consequence (usually something unpleasant) that follows a behavior and
decreases the chances the behavior will occur again. As we use each scheme, it becomes better adapted to the world; in other words, it works better. The
process of accommodation is the key to developmental change. Through accommodation, we improve
our skills and reorganize our ways of thinking.
The information-processing theory breaks memory down into the sub-processes of encoding, storage
The short-term memory is extremely limited in capacity—it can contain only about 7 items at a time.
Lon-term memory is unlimited in capacity, and information is often organized and stored in terms of
According to Neo-Piagetians, older children and adults can solve complex problems such as those in
Piaget’s research because they can hold more pieces of information in their short-term memories at the
same time that younger children can.
People who have a strong sense of self-efficacy have higher expectation for success and will put forth
more effort and persistence when faced with a challenge. A person with low-efficacy has a lower
expectation for success, which is associated with avoidance when confronted with a difficult task.
1- piaget’s theory of cognitive development: reasoning develops in 4 universal stages from birth through
adolescence; in each stage, the child builds a different kind of scheme
2- information-processing theory: the computer is used as a model for human cognitive functioning;
encoding, storage, and retrieval processes change with age, causing changes in memory function; these
changes happen because of both brain maturation and practice.
3-Vygotsky’s sociocultural theory: cognitive development is strengthened through social interactions
that involve speaking during guided problem-solving tasks.
4- Bandura’s social-cognitive theory: people learn from models; what they learn from a model depends
on how they interpret the situation cognitively and emotionally.
biological theories focus on the contribution of hereditary genetic mechanisms in development
geneticists distinguish between the genotype (the pattern of inherited genes) and the phenotype (the
individual’s observable characteristics)
inherited and acquired epigenetic mechanisms regulate gene expression
evolutionary psychology is the view that, through a process of biological evolution, the mind, like the
body, has been shaped by natural selection to serve adaptive functions and promote survival.
Evolutionary developmental psychology theorists suggest that heredity and the environment interact in
determining the cognitive abilities that promote survival and adaptation at different times across the
lifespan. Freud emphasized that behavior is governed by both conscious and unconscious motives and that the
personality develops in steps
Erikson emphasized social forces more than unconscious drives as motives for development. He
proposed that personality develops in eight psychosocial stages over the course of the lifespan.
Humanistic theorist Abraham Maslow suggested that individuals are motivated to fulfill inner needs in
order to ultimately attain self-actualization
Classical conditioning-learning though association of stimuli-helps explain the acquisition of emotional
Operant conditioning involves learning to repeat or stop behaviors because of their consequences
Piaget focused on the development of logical thinking. He discovered that such thinking develops across
4 childhood and adolescent stages
Information-processing theory uses the computer as a model to explain intellect