CEREBRAL LATERALITY:
RIGHT BRAIN/LEFT BRAIN
Dominant brain and dumb brain
SPLIT-BRAIN RESEARCH
Split-brain surgery: when the corpus callosum is
cut to reduce severity of epileptic seizures
 Has shown that right hemisphere controls the
left side of the body and vice versa

SPLIT-BRAIN RESEARCH
Roger Sperry and Michael Gazzaniga studies
 Showed language is housed in the left
hemisphere
 Right hemisphere: visual-spatial tasks (colors,
arranging, recognizing)

HEMISPHERIC SPECIALIZATION IN
THE INTACT BRAIN
Perceptual Asymmetries: left-right imbalances
btwn cerebral hemispheres in the speed of visual
or auditory processing
 Studied to show which hemisphere is more
dominant in certain situations

HEMISPHERE SPECIALIZATION
LEFT HEMISPHERE
Better at:
 Verbal processing
 Language, speech,
reading, writing
 Possible: handling
emotions, links to
schizophrenia

RIGHT HEMISPHERE
Better at:
 Nonverbal processing
 Spatial, musical, and
visual recognition
 Possible: expression of
emotions, recognition
of other’s emotions;
classical conditioning,
links to depression

ENDOCRINE SYSTEM
Glands that secrete chemicals (hormones) into
the bloodstream that help control body
functioning
 30 different hormones
 Hypothalamus controls the endocrine system

ENDOCRINE SYSTEM
Hypothalamus connected to the…
 Pituitary gland: releases variety of hormones
that fan out in the body, stimulating actions in
other endocrine glands
 Pituitary gland is the “master gland” of the
endocrine system

HEREDITY AND BEHAVIOR
Behavioral genetics: interdisciplinary field that
studies the influence of genetic factors on
behavioral traits
CHROMOSOMES AND GENES
Chromosomes: strands of DNA molecules that
carry genetic info.
 46 chromosomes (23 pairs, 1 chromosome from
each parent)
 Each chromosome contains Genes: DNA segments
that serve as the key functional units in
hereditary transmission

CHROMOSOMES AND GENES
Homozygous condition: two genes in specific pair
are the same
 Heterozygous condition: 2 genes in a specific pair
are different
 When heterozygous, the dominant gene is
expressed

GENOTYPE VS. PHENOTYPE
Genotype: a person’s genetic makeup
 Phenotype: ways in which a person’s genotype is
manifested in observable characteristics

POLYGENIC INHERITANCE
Polygenic traits: characteristics that are
influenced by more than one pair of genes
 Most human characteristics are polygenic

RESEARCH METHODS FOR
INVESTIGATING HEREDITARY
INFLUENCE
Family studies: examining blood relatives to see
how much they resemble one another on a
specific trait
 Shows traits that “run in the family”
 Only correlative

RESEARCH METHODS CONTINUED
Twin studies: comparing the resemblance of
identical and fraternal twins w/respect to a trait
 Identical (monozygotic) twins: one zygote, split
 Fraternal (dizygotic) twins: 2 eggs fertilized by
different sperm cells, 2 separate zygotes

RESEARCH METHODS CONTINUED
Adoption studies: examining resemblance btwn
adopted children and both their biological and
adoptive parents
 Usually done only with babies given up at birth

GENETIC MAPPING
Def: process of determining the location and
chemical sequence of specific genes on specific
chromosomes
 Technology only allows for single gene mapping
 Most human traits are polygenic
