ap psych unit 1

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 views traits and behaviors as arising from the interaction of nature and nurture.

natural selection

the principle that the inherited traits enabling 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.

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.

mutation

a random error in gene replication that leads to a change.

environment

every nongenetic influence, from prenatal nutrition to our experiences of the people and things around us.

heredity

the genetic transfer of characteristics from parents to offspring.

genes

the biochemical units of heredity.

genome

the complete instructions for making an organism.

identical (monozygotic) twins

individuals who developed from a single fertilized egg that split in two, creating two genetically identical organisms.

fraternal (dizygotic) twins

individuals who developed from separate fertilized eggs. They are genetically no closer than ordinary siblings, but they shared a prenatal environment.

interaction

the interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity).

epigenetics

“above” or “in addition to” (epi) genetics; the study of the molecular mechanisms by which environments can influence genetic expression (without a DNA change).

nervous system

the body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems.

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.

nerves

bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sensory organs.

sensory (afferent) neurons

neurons that carry incoming information from the body’s tissues and sensory receptors to the brain and spinal cord.

motor (efferent) neurons

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands.

interneurons

neurons within the brain and spinal cord; they communicate internally and process information between the sensory inputs and motor outputs.

somatic nervous system

the division of the peripheral nervous system that controls the body’s skeletal muscles. Also called the skeletal nervous system.

autonomic 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). Its sympathetic division arouses; its parasympathetic division calms.

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy.

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy.

reflex

a simple, automatic response to a sensory stimulus, such as the knee-jerk reflex.

neuron

a nerve cell; the basic building block of the nervous system.

cell body

the part of a neuron that contains the nucleus; the cell’s life-support center.

dendrites

a neuron’s bushy, branching extensions that receive and integrate messages, conducting impulses toward the cell body.

axon

the segmented neuron extension that passes messages through its branches to other neurons or to muscles or glands.

myelin sheath

a fatty tissue layer encasing the axons of some neurons; it enables faster transmission as impulses hop from node to node.

glial cells (glia)

cells in the nervous system that support, nourish, and protect neurons; they may also play a role in learning, thinking, and memory.

action potential

a neural impulse; a brief electrical charge that travels down an axon.

threshold

the level of stimulation required to trigger a neural impulse.

refractory period

a brief resting pause that occurs after a neuron has fired; new action potentials cannot occur until the axon resets.

all-or-none response

a neuron’s reaction of either firing (with full strength) or not firing.

synapse

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron; the tiny gap is the synaptic gap or cleft.

neurotransmitters

chemical messengers that cross the synaptic gap between neurons, influencing whether the receiving neuron will generate a neural impulse.

reuptake

a neurotransmitter’s reabsorption by the sending neuron.

endorphins

“morphine within”; natural, opioid-like neurotransmitters linked to pain control and pleasure.

agonist

a molecule that increases a neurotransmitter’s action.

antagonist

a molecule that inhibits or blocks a neurotransmitter’s action.

endocrine system

the body’s “slow” chemical communication system; a set of glands and fat tissue that secrete hormones into the bloodstream.

hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues.

psychoactive drug

a chemical substance that alters the brain, causing changes in perceptions and moods.

substance use disorder

a disorder characterized by continued substance use despite resulting life disruption.

depressants

drugs that reduce neural activity and slow body functions.

tolerance

the diminishing effect with regular use of the same dose of a drug, requiring larger doses to achieve the effect.

addiction

compulsive substance use (or sometimes behaviors, like gambling) that continues despite harmful consequences.

withdrawal

the discomfort and distress that follow discontinuing an addictive drug or behavior.

barbiturates

drugs that depress central nervous system activity, reducing anxiety but impairing memory and judgment.

opioids

opium and its derivatives; they depress neural activity, temporarily lessening pain and anxiety.

stimulants

drugs that excite neural activity and speed up body functions.

hallucinogens

psychedelic (“mind-manifesting”) drugs that distort perceptions and evoke sensory images in the absence of sensory input.

near-death experience

an altered state of consciousness reported after a close brush with death; often similar to drug-induced hallucinations.

biological psychology

the scientific study of the links between biological (genetic, neural, hormonal) and psychological processes.

biopsychosocial approach

an integrated approach that incorporates biological, psychological, and social-cultural levels of analysis.

levels of analysis

the differing complementary views — from biological to psychological to social-cultural — for analyzing any given phenomenon.

neuroplasticity

the brain’s ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience.

lesion

tissue destruction; may occur naturally, surgically, or experimentally.

EEG (electroencephalogram)

a recording of electrical activity sweeping across the brain’s surface, measured by electrodes on the scalp.

MEG (magnetoencephalography)

a brain-imaging technique that measures magnetic fields from the brain’s electrical activity.

CT (computed tomography) scan

a series of X-ray photos taken from different angles and combined by computer to show brain structure.

PET (positron emission tomography) scan

a technique for detecting brain activity by tracking where radioactive glucose goes while the brain performs a task.

MRI (magnetic resonance imaging)

a technique using magnetic fields and radio waves to produce detailed images of soft tissue and show brain anatomy.

fMRI (functional MRI)

a technique showing blood flow and brain activity by comparing successive MRI scans; reveals both function and structure.

hindbrain

includes the medulla, pons, and cerebellum; directs survival functions like breathing and balance.

midbrain

connects the hindbrain with the forebrain; controls some motor movement and transmits auditory and visual information.

forebrain

consists of the cerebral cortex, thalamus, and hypothalamus; manages cognitive, sensory, and motor functions.

brainstem

the central core of the brain; responsible for automatic survival functions.

medulla

the base of the brainstem; controls heartbeat and breathing.

thalamus

the brain’s sensory control center; directs messages to sensory areas and transmits replies to the cerebellum and medulla.

reticular formation

a nerve network that travels through the brainstem into the thalamus; filters information and helps control arousal.

cerebellum

the “little brain” at the rear of the brainstem; processes sensory input, coordinates movement and balance, and enables nonverbal learning.

limbic system

neural system below the cerebral hemispheres including the amygdala, hypothalamus, hippocampus, thalamus, and pituitary gland; associated with emotions and drives.

amygdala

two neural clusters in the limbic system linked to emotion.

hypothalamus

lies below the thalamus; directs maintenance activities (eating, drinking, body temperature), helps control the endocrine system, and is linked to emotion and reward.

hippocampus

a neural center in the limbic system that helps process explicit (conscious) memories for storage.

cerebral cortex

the intricate fabric of neural cells covering the cerebral hemispheres; the body’s ultimate control and information-processing center.

frontal lobes

behind the forehead; enable speaking, muscle movement, and higher-order thinking such as planning and judgment.

parietal lobes

at the top of the head toward the rear; receive sensory input for touch and body position.

occipital lobes

at the back of the head; include areas that receive visual information.

temporal lobes

above the ears; include auditory areas and are involved in language processing.

motor cortex

located at the rear of the frontal lobes; controls voluntary movements.

somatosensory cortex

located at the front of the parietal lobes; registers and processes touch and movement sensations.

association areas

regions of the cortex involved in higher mental functions such as learning, remembering, thinking, and speaking.

neurogenesis

the formation of new neurons.

corpus callosum

the large band of neural fibers connecting the two hemispheres and carrying messages between them.

split brain

a condition resulting from surgery that cuts the fibers (mainly of the corpus callosum) connecting the two hemispheres.