Unit 1.1
Heredity (nature): genetic or predisposed characteristics that influence physical, behavioral, and mental
traits and processes.
How do genes work?
- Genes contain information for synthesis of specific proteins
- The proteins made can be hormones (that affect bodily processes), enzymes (that affect rate of
cellular reactions), or structural components of the body
Examples of heredity at work: Eye color & fur color are determined by genes
Environmental factors (nurture): the external factors that one experiences, such as family interactions or
education.
Example of environmental factors at work: Adverse life experiences (e.g., losing a job, death of a loved
one, divorce) can increase the risk of depression
Nature-nurture interaction
- Environmental influences can trigger certain genes to be “switched on” or “switched off”
o For some survivors, Holocaust exposure affects the way FKBP5 stress gene is expressed
(i.e., used to make proteins) -> Holocaust survivors have a higher risk of depression and
anxiety
- Genes may provide the blueprint which are shaped by the environment
o E.g., children born from genetically tall parents may not reach their potential height if
they are not provided with adequate nutrition
nature-nurture issue: the longstanding controversy over the relative contributions that genes and
experience make to the development of psychological traits and behaviors. Today’s science sees traits
and behaviors arising from the interaction of nature and nurture
mutation: a random error in gene replication that leads to a change.
natural selection: the principle that inherited traits that better enable an organism to survive and
reproduce in a particular environment will (in competition with other trait variations) most likely be
passed on to succeeding generations; proposed by Charles Darwin
- Individuals have different traits due to mutations in their DNA, which produce different versions
of the same gene (also called alleles)
o different alleles mean that you may get different versions of the same characteristics
(e.g., all humans have an eye but some have blue eyes and others have brown eyes)
• some individuals with certain traits have better chances of surviving in the environment. Others
do not.
• those who can adapt and survive will reproduce and pass down their genes, and therefore, their
traits over many generations, the traits of those individuals who survive will be seen more in a
population
,evolutionary psychology: the study of the evolution of behavior and the mind, using principles of natural
selection.
behavior genetics: the study of the relative power and limits of genetic and environmental influences on
behavior
Examples of evolutionary psychology
How might an evolutionary psychologist explain male-female differences in sexuality and mating
preferences?
• Women tend to be more selective than men when choosing sexual partners.
• Evolutionary psychologists reason that men’s attraction to multiple healthy, fertile-appearing
partners increases their chances of spreading their genes widely.
• Because women incubate and nurse babies, they increase their own and their children’s chances
of survival by searching for mates with the potential for long-term investment in their joint
offspring
What are the key criticisms of evolutionary explanations of human sexuality?
Critics argue that evolutionary psychologists
1. start with an effect and work backward to an explanation
2. do not recognize social and cultural influences
3. absolve people from taking responsibility for their sexual behavior
,central nervous system (CNS): the brain and spinal cord
peripheral nervous system (PNS): the sensory and motor neurons that connect the central nervous
system (CNS) to the rest of the body.
somatic nervous system: the division of the peripheral nervous system that controls the body’s skeletal
muscles
autonomic [aw-tuh-NAHM-ik] nervous system (ANS): the part of the peripheral nervous system that
controls the glands and the muscles of the internal organs (such as the heart).
sympathetic nervous system: the division of the autonomic nervous system that arouses the body,
mobilizing its energy.
• Dilates pupils
• Accelerates heartbeat
• Inhibits digestion in the stomach
• Stimulates glucose release in the liver
• Stimulates release of adrenaline/epinephrine and noradrenaline/norepinephrine in the adrenal
gland
• Stimulates ejaculation in males
, parasympathetic nervous system: the division of the autonomic nervous system that calms the body,
conserving its energy. (“rest and digest”)
• Contracts pupils
• Slows heartbeat
• Stimulates digestion
• Stimulates gallbladder
• Contracts bladder
• Allows blood flow to sex organs
Heredity (nature): genetic or predisposed characteristics that influence physical, behavioral, and mental
traits and processes.
How do genes work?
- Genes contain information for synthesis of specific proteins
- The proteins made can be hormones (that affect bodily processes), enzymes (that affect rate of
cellular reactions), or structural components of the body
Examples of heredity at work: Eye color & fur color are determined by genes
Environmental factors (nurture): the external factors that one experiences, such as family interactions or
education.
Example of environmental factors at work: Adverse life experiences (e.g., losing a job, death of a loved
one, divorce) can increase the risk of depression
Nature-nurture interaction
- Environmental influences can trigger certain genes to be “switched on” or “switched off”
o For some survivors, Holocaust exposure affects the way FKBP5 stress gene is expressed
(i.e., used to make proteins) -> Holocaust survivors have a higher risk of depression and
anxiety
- Genes may provide the blueprint which are shaped by the environment
o E.g., children born from genetically tall parents may not reach their potential height if
they are not provided with adequate nutrition
nature-nurture issue: the longstanding controversy over the relative contributions that genes and
experience make to the development of psychological traits and behaviors. Today’s science sees traits
and behaviors arising from the interaction of nature and nurture
mutation: a random error in gene replication that leads to a change.
natural selection: the principle that inherited traits that better enable an organism to survive and
reproduce in a particular environment will (in competition with other trait variations) most likely be
passed on to succeeding generations; proposed by Charles Darwin
- Individuals have different traits due to mutations in their DNA, which produce different versions
of the same gene (also called alleles)
o different alleles mean that you may get different versions of the same characteristics
(e.g., all humans have an eye but some have blue eyes and others have brown eyes)
• some individuals with certain traits have better chances of surviving in the environment. Others
do not.
• those who can adapt and survive will reproduce and pass down their genes, and therefore, their
traits over many generations, the traits of those individuals who survive will be seen more in a
population
,evolutionary psychology: the study of the evolution of behavior and the mind, using principles of natural
selection.
behavior genetics: the study of the relative power and limits of genetic and environmental influences on
behavior
Examples of evolutionary psychology
How might an evolutionary psychologist explain male-female differences in sexuality and mating
preferences?
• Women tend to be more selective than men when choosing sexual partners.
• Evolutionary psychologists reason that men’s attraction to multiple healthy, fertile-appearing
partners increases their chances of spreading their genes widely.
• Because women incubate and nurse babies, they increase their own and their children’s chances
of survival by searching for mates with the potential for long-term investment in their joint
offspring
What are the key criticisms of evolutionary explanations of human sexuality?
Critics argue that evolutionary psychologists
1. start with an effect and work backward to an explanation
2. do not recognize social and cultural influences
3. absolve people from taking responsibility for their sexual behavior
,central nervous system (CNS): the brain and spinal cord
peripheral nervous system (PNS): the sensory and motor neurons that connect the central nervous
system (CNS) to the rest of the body.
somatic nervous system: the division of the peripheral nervous system that controls the body’s skeletal
muscles
autonomic [aw-tuh-NAHM-ik] nervous system (ANS): the part of the peripheral nervous system that
controls the glands and the muscles of the internal organs (such as the heart).
sympathetic nervous system: the division of the autonomic nervous system that arouses the body,
mobilizing its energy.
• Dilates pupils
• Accelerates heartbeat
• Inhibits digestion in the stomach
• Stimulates glucose release in the liver
• Stimulates release of adrenaline/epinephrine and noradrenaline/norepinephrine in the adrenal
gland
• Stimulates ejaculation in males
, parasympathetic nervous system: the division of the autonomic nervous system that calms the body,
conserving its energy. (“rest and digest”)
• Contracts pupils
• Slows heartbeat
• Stimulates digestion
• Stimulates gallbladder
• Contracts bladder
• Allows blood flow to sex organs
