unit two - research methods Flashcards
the study of the relative power and limits of genetic and environmental influences on behavior.
behavior genetics
the genetic transfer of characteristics from parents to offspring.
heredity
every nongenetic influence, from prenatal nutrition to the people and things around us.
environment
threadlike structures made of DNA molecules that contain the genes.
chromosomes
a complex molecule containing the genetic information that makes up the chromosomes.
dna (deoxyribonucleic acid)
the biochemical units of heredity that make up the chromosomes; segments of DNA capable of synthesizing proteins.
genes
the complete instructions for making an organism, consisting of all the genetic material in that organism’s chromosomes.
genome
develop from a single fertilized egg that splits in two, creating two genetically identical organisms.
identical twins (monozygotic)
develop from separate fertilized eggs. They are genetically no closer than ordinary brothers and sisters, but they share a prenatal environment.
fraternal twins (dizygotic)
the proportion of variation among individuals in a group that we can attribute to genes. The heritability of a trait may vary, depending on the range of populations and environments studied.
heritability
the interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity).
interaction
the subfield of biology that studies the molecular structure and function of genes.
molecular genetics
the study of how the structure and function of genes interact with our environment to influence behavior.
molecular behavior genetics
“above” or “in addition to” (epi) genetics; the study of environmental influences on gene expression that occur without a DNA change.
epigenetics
the study of the evolution of behavior and the mind, using principles of natural selection.
evolutionary psychology
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.
natural selection
a random error in gene replication that leads to a change.
mutation
a culturally modeled guide for how to act in various situations.
social script
a nerve cell; the basic building block of the nervous system.
neuron
the part of a neuron that contains the nucleus; the cell’s life support center.
cell body
a neuron’s often bushy, branching extensions that receive and integrate messages, conducting impulses toward the cell body.
dendrites
the neuron extension that passes messages through its branches to other neurons or to muscles or glands.
axon
a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next.
myelin sheath
cells in the nervous system that support, nourish, and protect neurons; they also play a role in learning, thinking, and memory.
glial cells (glia)
a neural impulse; a brief electrical charge that travels down an axon.
action potential
the level of stimulation required to trigger a neural impulse.
threshold
in neural processing, a brief resting pause that occurs after a neuron has fired; subsequent action potentials cannot occur until the axon returns to its resting state.
refractory period
a neuron’s reaction of either firing (with a full strength response) or not firing.
all-or-none response
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or synaptic cleft.
synapse
chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.
neurotransmittersw
a neurotransmitter’s reabsorption by the sending neuron.
reuptake
“morphine within”—natural, opiate-like neurotransmitters linked to pain control and to pleasure.
endorphins
a molecule that increases a neurotransmitter’s action.
agonist
a molecule that inhibits or blocks a neurotransmitter’s action.
antagonist
the body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems.
nervous system
the brain and spinal cord.
central nervous system
the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body.
peripheral nervous system
bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sense organs.
nerves
neurons that carry incoming information from the body’s tissues and sensory receptors to the brain and spinal cord.
sensory (afferent) neurons
neurons that carry outgoing information from the brain and spinal cord to the muscles and glands.
motor (efferent) neurons
neurons within the brain and spinal cord; they communicate internally and process information between the sensory inputs and motor outputs.
interneurons
the division of the peripheral nervous system that controls the body’s skeletal muscles. Also called the skeletal nervous system.
somatic nervous system
the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.
autonomic nervous system
the division of the autonomic nervous system that arouses the body, mobilizing its energy.
sympathetic nervous system
the division of the autonomic nervous system that calms the body, conserving its energy.
parasympathetic nervous system
a simple, automatic response to a sensory stimulus, such as the knee-jerk response.
reflex
the body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream.
endocrine system
chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream and affect other tissues.
hormones
a pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress.
adrenal glands
the endocrine system’s most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.
pituitary glands
tissue destruction. A brain lesion is a naturally or experimentally caused destruction of brain tissue.
lesion
an amplified recording of the waves of electrical activity sweeping across the brain’s surface. These waves are measured by electrodes placed on the scalp.
electroencephalogram (ees)
a brain imaging technique that measures magnetic fields from the brain’s natural electrical activity.
magnetoencephalography (meg)
a series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice of the brain’s structure. (Also called CAT scan.)
ct scan (computed topography)
a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task.
PET scan (positron emission tomography)
a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. MRI scans show brain anatomy.
MRI (magnetic resonance imaging)
a technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans. fMRI scans show brain function as well as structure.
fMRI (functional MRI)
the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions.
brainstem
the base of the brainstem; controls heartbeat and breathing.
medulla
the brain’s sensory control center, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla.
thalamus
a nerve network that travels through the brainstem into the thalamus and plays an important role in controlling arousal.
reticular formation
the “little brain” at the rear of the brainstem; functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory.
cerebellum
neural system (including the amygdala, hypothalamus, and hippocampus) located below the cerebral hemispheres; associated with emotions and drives.
limbic system
two lima-bean-sized neural clusters in the limbic system; linked to emotion.
amygdala
a neural structure lying below (hypo) the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.
hypothalamus
a neural center located in the limbic system; helps process for storage of explicit (conscious) memories of facts and events.
hippocampus
