Chapter 4 Nature/Nurture Evolution Behavior-Genetics
Jan 18, 2018
Chapter 4
Nature/NurtureEvolutionBehavior-Genetics
The Nature of Behavior and Mental ProcessesChromosomesHormonesBrain Structures/Chemicals
Genes: Our Biological Blueprint
Chromosomes 23 Pair Contain genetic material
DNA (deoxyribonucleic acid) Building blocks of the chromosomes has two strands-forming a “double helix”
Genes segment of DNA capable of synthesizing a
protein
Gender and Nature 23rd Chromosome = Sex
X from egg X or Y from spermXX = FemaleXY = Male
Testosterone (androgen) Levels/Testes Estrogen Levels/Ovaries Brain Development Identity
Cognitive Differences No differences for most cognitive abilities Verbal, reading, and writing— females
consistently score higher Spatial skills —males outscore females on
mentally rotating objects, females score better on remembering locations of objects
Math Skills— males score slightly better than females
The Role of HormonesHormones are chemicals that control bodily responses such as emotions, growth, and sexuality.
Males have more androgen.
Females have more estrogen.
Hormones play a lesser role in human development and behavior than they do in animals.
The sex hormones are estrogen and androgen.
The Nurture of Behavior and Mental Processes
Social Learning TheoryParentingPeersCultureNorms
The Nurture of Gender Gender Role
a set of expected behaviors for males and females
Gender Identity one’s sense of being male or female
Gender-typing the acquisition of a traditional masculine or
feminine role
Gender Role Stereotypes
The beliefs and expectations people hold about the typical characteristics, preferences, and behaviors of men and women
“I’m Glad I’m a Boy, I’m Glad I’m a Girl”
Gender Role Development Between ages 2-3 years, children can identify
themselves and other children as boys or girls. The concept of gender or sex, however is
based more on outward characteristics such as clothing.
Toddler girls tend to play more with dolls and ask for help more than boys
Toddler boys tend to play more with trucks and wagons, and tend to play more actively
After age 3 years we see consistent gender differences in preferred toys and activities
The Nurture of Gender Social Learning Theory
theory that we learn social behavior by observing and imitating and by being rewarded or punished
Gender Schema Theory theory that children learn from their cultures
a concept of what it means to be male and female and that they adjust their behavior accordingly
The Nurture of Gender
Two theories of gender typing
David(Brenda) Reimer
What, if any, aspects of David’s development support the nature theory of gender?
What aspects support the nurture theory?
Personality Differences
No significant differences between men and women on most characteristics
Women tend to be more nurturant than men (very broad)
Men tend to be more assertive than women (very broad)
Male/Female DifferencesThe only activity that is clearly defined along gender lines is reproduction. All other activities are shared by both sexes to different degrees.
Nurturance: Women generally show more empathy, but males can also be nurturing. No one has proven the existence of strong maternal instinct in humans.
Physical activity: Boys start out more physically active. By adulthood, differences in activity levels between genders have disappeared.
Aggression: Males are aggressive in more situations than females. Females do show aggression in some situations, however.
Mathematical AbilityStudies are not clear and have not as yet conclusively shown that males are innately better at math.
Males do better than females on the SAT math section, but study findings have not been consistent.
Teachers and parents have higher expectations for males.
Females may avoid difficult areas such as math.
Verbal Ability Includes not just speaking but also word problems, reading and writing. Generally, girls do better than males until early adolescence.
Evolutionary Psychology
Evolutionary Psychology the study of the evolution of behavior
and the mind, using the principles of natural selection
Gender in psychology, the characteristics,
whether biologically or socially influenced, by which people define male and female
Evolutionary Psychology
Natural Selection Mutations
random errors in gene replication that lead to a change in the sequence of nucleotides
the source of all genetic diversity Maximizing Fitness
Maximizing the fitness of your gene pool by selecting a mate with healthy genes and thus increasing your chances of producing healthy offspring.
Evolutionary Psychology
Critiquing the Evolutionary Explanation
Evolutionary psychologists make too many hindsight explanations.
Behavior Genetics
Behavior Genetics study of the relative power and limits of
genetic and environmental influences on behavior
Environment every nongenetic influence, from
prenatal nutrition to the people and things around us
Behavior Genetics Identical (monozygotic)
Twins develop from a single
fertilized egg that splits in two, creating two genetically identical organisms
Fraternal (dizygotic) Twins develop from separate eggs genetically no closer than
brothers and sisters, but they share the fetal environment
Identicaltwins
Fraternaltwins
Samesex only
Same oropposite sex
Behavior Genetics Temperament
a person’s characteristic emotional reactivity and intensity
Heritability the proportion of variation among
individuals that we can attribute to genes may vary, depending on the range of
populations and environments studied
Behavior Genetics Interaction
the dependence of the effect of one factor (such as environment) on another factor (such as heredity)
Molecular Genetics the subfield of biology that studies the
molecular structure and function of genes
Environmental Influence
Experience affects brain development
Impoverishedenvironment
Rat braincell
Rat braincell
Enrichedenvironment