Chapter 3: Recent Perspectives on Social and Personality Development
All the new theories acknowledge the two points that Piaget sought to emphasize, namely
that (1) developing persons are active rather than passive beings, and (2) development
results from a variety of complex transactions between the forces of nature and nurture.
Modern Evolutionary Perspectives
Gesell’s view was that children, much like plants, simply ―bloomed,‖ following a pattern
and timetable laid out in their genes; how parents raised their young was thought to be of
Ethology: the scientific study of the evolutionary basis of behaviour and the
contributions of such evolved responses to a species survival and development.
Assumptions of Classical Ethology
According to Lorenz and Tinbergen, members of all animal species are born with a
number of ―biologically programmed‖ behaviours that are (1) products of evolution and
(2) adaptive in that they contribute to survival.
Natural selection: an evolutionary process, proposed by Charles Darwin, stating that
individuals with characteristics that promote adaptation to the environment will survive,
reproduce, and pass these adaptive characteristics to offspring; those lacking these
adaptive characteristics will eventually die out.
Ethologists focus on inborn or instinctual responses that (1) members of a species share
and (2) seem to steer individuals along similar developmental paths.
Ethology and Human Development
Human ethologists, not only believe that children display a wide variety of
preprogrammed behaviours; they also claim that each of these responses promotes a
particular kind of experience that will help the individual to survive and develop
A critical period is a short part of the life cycle during which the developing organism is
uniquely sensitive or responsive to specific environmental influences; outside this period
the same environmental events or influences are thought to have no lasting effects
(Ethologists believe learning is very important).
Sensitive period: refers to a time that is optimal for the emergence of particular
competencies or behaviours and in which the individual is particularly sensitive to
environmental influences (can learn outside of it but harder to foster).
Some ethologists believe that the first three years of life are a sensitive period.
Modern Evolutionary Theory
Preselected, adaptive motives and behaviours are those that ensure the survival and
spread of the individual’s genes. Men’s and women’s mating preferences do tend to confirm these predictions, with men
the world over being more inclined than women to seek mates who are younger and
attractive, and women being more inclined to seek an older and kindly mate with ample
resources who is emotionally attracted to her.
A lengthy period of development, accompanied by the protections provided by older
individuals is adaptive in that it allows juveniles to acquire all the physical and cognitive
competencies, knowledge, and social skills to occupy niches as productive members of
modern human cultures.
Contributions and Criticisms of Evolutionary Viewpoints
The ethologists have made a major methodological contribution by showing us the value
of (1) studying human development in normal, everyday settings and (2) comparing
human development with that of other species.
Altruism: a selfless concern for the welfare of others that is expressed through prosocial
acts such as sharing, cooperating, comforting others, or helping.
Very hard to test.
A just-so story is an explanation that sounds plausible and in fact may be true but is not
supported by any conclusive evidence.
Some strong, genetically influenced attributes can easily be modified by experience.
Behavioural Genetics: Biological Bases for Individual Differences
Behavioural genetics: the scientific study of how genotype interacts with environment to
determine behavioural attributes such as intelligence, personality, and mental health.
Genotype: the set of genes one inherits.
Phenotype: one’s observable characteristics and behaviours.
Behavioural geneticists claim that most behavioural attributes are the end product of a
long and involved interplay between hereditary predispositions and environmental
Behavioural geneticists focus on the biological bases for variation among members of a
Methods of Studying Hereditary Influences
Heritability: the amount of variation in a trait or a class of behaviour that is attributable
to hereditary factors.
Selective breeding experiment: a method of studying genetic influences by determining
whether traits can be bred in animals through selective mating.
Family Studies Persons who live in the same household are compared to see how similar they are on one
or more attributes.
Kinship: the extent to which they have the same genes.
Twin study: a study in which sets of twins that differ in kinship are compared to
determine heritability of attribute.
Adoption design: focuses on adoptees who are genetically unrelated to other members of
their adoptive families.
Estimating the Contributions of Genes and Environment
Behavioural geneticists rely on some reasonably simple mathematical calculations to
determine (1) whether a trait is genetically influenced and (2) the degree to which
heredity and environment account for individual differences in that trait.
Concordance rates: the percentages of pairs of people in which both members of the
pair display the trait if one member does.
The correlations become higher when pairs of people are more closely related genetically
and are highest when the pairs are identical twins.
Heritability coefficient: a numerical estimate, ranging from .00 to +1.00, of the amount
of variation in an attribute that is due to hereditary factors. H= (r identical twins – r
fraternal twins) x 2
Nonshared Environmental Influences (NSE)
Nonshared environmental influence: an environmental influence that people living
together do not share and that should make these individuals different from one another.
NSE= 1 – r(identical twins reared together)
Shared Environmental Influences (SE)
Shared environmental influence: an environmental influence that people living together
share and that should make these individuals similar to one another.
SE = 1 – (H + NSE)
Hereditary Contributions to Personality and Mental Health
Introversion/extroversion: the extent to which a person is shy, retiring, and
uncomfortable around others versus outgoing and socially oriented—shows about the
same moderate level of heritability as IQ does.
Empathic concern: a measure of the extent to which an individual recognizes the needs
of others and is concerned about their welfare.
How Much Genetic Influence Identical twins are more similar to each other than are fraternal twins.
Personality is strongly influenced by environmental factors.
Which Aspects of Environment Influence Personality
Aspects of the home environment that all family members share must not contribute
much to the development of personality.
The aspects of environment that contribute most heavily to personality are nonshared
Measuring the Effects of Nonshared Environments
The greater the differences in parental treatment and other experiences that siblings
report, the more dissimilar siblings are in their personalities.
When it comes to the shaping of many other basic personality traits, it is the nonshared
experiences people have that contribute most to their phenotypes.
Hereditary Contributions to Behaviour Disorders and Mental Illnesses
Schizophrenia: a serious mental illness characterized by severe disturbances in logical
thinking, emotional expression, and social behaviour, which typically emerges in late
adolescence or early adulthood (genetically influenced).
It may be possible someday to prevent the onset of most genetically influenced disorders
should we (1) learn more about the environmental triggers that precipitate these
disturbances while (2) striving to develop interventions or therapeutic techniques that will
help ―high-risk‖ individuals to maintain their emotional stability in the face of