classical conditioning
learning to make an involuntary (reflex) response to a stimulus other than the original, natural stimulus that normally produces the reflex
unconditioned stimulus (UCS)
a naturally occurring stimulus that leads to an involuntary (reflex) response
unconditioned response (UCR)
an involuntary (reflex) response to a naturally occurring or unconditioned stimulus
neutral stimulus (NS)
stimulus that has no effect on the desired response
conditioned stimulus (CS)
stimulus that becomes able to produce a learned reflex response by being paired with the original unconditioned stimulus
conditioned response (CR)
learned reflex response to a conditioned stimulus
stimulus generalization
the tendency to respond to a stimulus that is only similar to the original conditioned stimulus with the conditioned response
stimulus discrimination
the tendency to stop making a generalized response to a stimulus that is similar to the original conditioned stimulus because the similar stimulus is never paired with the unconditioned stimulus
extinction
the disappearance or weakening of a learned response following the removal or absence of the unconditioned stimulus (in classical conditioning) or the removal of a reinforcer (in operant conditioning)
spontaneous recovery
the reapperarance of a learned response after extinction has occurred
higher-order conditioning
occurs when a strong conditioned stimulus is paired with a neutral stimulus, causing the neutral stimulus to become a second conditioned stimulus
conditioned emotional response (CER)
emotional response that has become classically conditioned to occur to learned stimuli, such as a fear of dogs or the emotional reaction that occurs when seeing an attractive person
vicarious conditioning
classical conditioning of a reflex response or emotion by watching the reaction of another person
conditioned taste aversion
development of a nausea or aversive response to a particular taste because that taste was followed by a nausea reaction, occurring after only one association
biological preparedness
referring to the tendency of animals to learn certain associations, such as taste and nausea, with only one or a few pairings due to the survival value of the learning
stimulus substitution
original theory in which Pavlov stated that classical conditioning occurred because the conditioned stimulus became a substitute for the unconditioned stimulus by being paired closely together
cognitive perspective
modern theory in which classical conditioning is seen to occur because the conditioned stimulus provides information or an expectancy about the coming of the unconditioned stimulus
operant conditioning
the learning of voluntary behavior through the effects of pleasant and unpleasant consequences to responses
law of effect
law stating that if an action is followed by a pleasurable consequence, it will tend to be repeated, and if followed by an unpleasant consequence, it will tend not to be repeated
operant
any behavior that is voluntary
reinforcement
any event or stimulus that, when following a response, increases the probability that the response will occur again
reinforcers
any events or objects that, when following a response, increase the likelihood of that response occurring again
primary reinforcer
any reinforcer that is naturally reinforcing by meeting a basic biological need, such as hunger, thirst, or touch
secondary reinforcer
any reinforcer that becomes reinforcing after being paired with a primary reinforcer, such as praise, tokens, or gold stars
positive reinforcement
the reinforcement of a response by the addition or experience of a pleasurable stimulus
negative reinforcement
the reinforcement of a response by the removal, escape from, or avoidance of an unpleasant stimulus
partial reinforcement effect
the tendency for a response that is reinforced after some, but not all, correct responses to be very resistant to extinction
continuous reinforcement
the reinforcement of each and every correct response
fixed interval schedule of reinforcement
schedule of reinforcement in which the interval of time that must pass before reinforcement becomes possible is always the same
variable interval schedule of reinforcement
schedule of reinforcement in which the interval of time that must pass before reinforcement becomes possible is different for each trial or event
fixed ratio schedule of reinforcement
schedule of reinforcement in which the number of responses required for reinforcement is always the same
variable ratio schedule of reinforcement
schedule of reinforcement in which the number of responses required for reinforcement is different for each trial or event
punishment
any event or object that, when following a response, makes that response less likely to happen again
punishment by application
the punishment of a response by the addition or experience of an unpleasant stimulus
punishment by removal
the punishment of a response by the removal of a pleasurable stimulus
discriminative stimulus
any stimulus, such as a stop sign or a doorknob, that provides the organism with a cue for making a certain response in order to obtain reinforcement
shaping
the reinforcement of simple steps in behavior that lead to a desired, more complex behavior
successive approximations
small steps in behavior, one after the other, that lead to a particular goal behavior
instinctive drift
tendency for an animal's behavior to revert to genetically controlled patterns
behavior modification
the use of operant conditioning techniques to bring about desired changes in behavior
token economy
type of behavior modification in which desired behavior is rewarded with tokens
applied behavior analysis (ABA)
modern term for a form of functional analysis and behavior modification that uses a variety of behavioral techniques to mold a desired behavior or response
biofeedback
use of feedback about biological conditions to bring involuntary responses, such as blood pressure and relaxation, under voluntary control
neurofeedback
form of biofeedback using brain-scanning devices to provide feedback about brain activity in an effort to modify behavior
latent learning
learning that remains hidden until its application becomes useful
insight
the sudden perception of relationships among various parts of a problem, allowing the solution to the problem to come quickly
learned helplessness
the tendency to fail to act to escape from a situation because of a history of repeated failures in the past
observational learning
learning new behavior by watching a model perform that behavior
learning/performance distinction
referring to the observation that learning can take place without actual performance of the learned behavior
Memory
Active system that receives information from the senses, puts it in a usable form, organizes and stores it, retrieves info from storage
Encoding
Set of mental operations people perform on sensory info to convert that info into a form that is usable in the brain's storage
Storage
Holding on to memory/information for some period of time
Retrieval
Getting the information out of storage
Information-processing model
Focuses on the way information is handled/processed through different systems of memory; encoding, storage, retrieval are part of this process (similar to computer)
Parallel distributed processing model
Memory processes proposed to take place at the same time over a large network of neural connections
Levels-of-processing model
Model of memory that assumes information that is more deeply processed, or processed according to its meaning rather than just the sound or characteristics; will be remembered longer
Sensory memory
First stage of memory; information enters nervous system through sensory systems
Iconic memory
Visual sensory memory, lasting only a fraction of a second
Eidetic imagery
Ability to access a visual memory over a long period of time
Echoic memory
Brief memory of something a person has heard
Short-term memory
Held for 30 seconds or more; brief (3-5 items)
Selective attention
Ability to focus on only one stimulus from all sensory input (STM system)
Working memory
Active system that processes information in short-term memory
Maintenance rehearsal
Continuing to play attention to information to be memorized
Long-term memory
Where information is placed to be kept more or less permanently
Elaborative rehearsal
Way of transferring information from STM to LTM by making that information meaningful
Non declarative (Implicit) memory
Memories for skills people know how to do (tying shoes, riding bike, etc.)
Declarative (explicit) memory
All the things people can know; facts and information
Anterograde amnesia
When new long-term declarative memories cannot be formed
Semantic memory
Awareness of meanings of words, concepts, terms, names, math skills, etc.
Episodic memory
Represent episodes from one's life
Semantic network model
Assumes information stored in the brain in a connected fashion with concepts that relate is closer physically than concepts not highly related
Retrieval cue
Stimulus for remembering
Encoding specificity
Tendency for memory of any kind of information to be improved if retrieval conditions are similar to conditions where information was encoded
Recall
Memories retrieved with few or no external clues
Recognition
Involves seeing or hearing information and matching it with memory
Serial position effect
Tendency of information at the bottom and top of list or information to be remembered more accurately than the middle
Primacy effect
When beginning words are remembered better than the middle
Recency effect
When ending words are remembered better than the middle
Automatic encoding
Long-term memories enter permanent storage with little to no effort
Flashbulb memories
Automatic encoding that takes place when unexpected events or episodes have strong emotional associations; the emotional reactions stimulate a released of hormones which enhances formation of LTM
Constructive processing
Memories "built" from pieces stored away at encoding
Hindsight bias
When people falsely believe they would have accurately predicted an outcome without having been told about it
Misinformation effect
Misleading information can become part of the memory affecting its accuracy
Encoding failure
Failure to process information into a memory
Decay
Fading into nothing from disuse; "use it or lose it
Proactive interference
Tendency for old material to get in the way of learning new information
Retroactive
Tendency for new material to get in the way of retrieving old information
Retrograde amnesia
Loss of memory from point of injury backwards
Consolidation
the changes that take place in the structure and functioning of neurons when a memory is formed.
retroactive interference
memory problem that occurs when newer information prevents or interferes with the retrieval of older information.
distributed practice
distributed practicespacing the study of material to be remembered by including breaks between study periods.
memory trace
physical change in the brain that occurs when a memory is formed.
disuse
another name for decay, assuming that memories that are not used will eventually decay and disappear.
curve of forgetting
a graph showing a distinct pattern in which forgetting is very fast within the first hour after learning a list and then tapers off gradually.
sensation
- process that occus when special receptors activate and allow the outside stimuli to become neural signals
transduction
the process of converting outside stimuli (light) into neural activity
jnd (diff threshold)
the smallest difference between 2 stimuli that is detectable 50% of the time (coffee and teaspoons)
absolute threshld
lowest level of stimulation that the person can consciously detect 50% of the time (candle 30 mph away on a clear, dark night)
habituation
brain's tendency to stop attending to stop attending to constant, unchanging information (ex. ac in the back, you don't notice until it stops making the noise)
sensory adaptation
tendency of the receptor cells to become less responsive to a stimulus that is unchanging (piercings)
visual accomodation
the change in the thickness of the lens as it focuses on objects that are far away or close
cornea
surface of the eye in clear membrane the protects the eye and adjusts the amount of light that enters the eye
aqueous humor
clear liquid behind the cornea that nourishes the eye
pupil
black part of eye
iris
colored part of the eye that changes pupil's shape to let in more or less with some focus
viterous humor
big red hole in the eye filled with liquid that nourishes and shapes the eye
Final stop in the retina
retina has ganglion, bipolar, rods and cones
rods
- in the back of the retina- responsible for sensitivity to black and white colors
cones
- retina receptor- responsible for colored vision and sharpness of vision
blindspot
area in retina where axons of retinal cells exit the eyes to form the optic nerve which is insensitive to light
dark adaptation
recovery of eye sensitivity to visual stimuli in darkness after being exposed to the bright light
light adaptation
recovery of eye sensitivity to visual stimuli in light after exposure to darkness
trichromatic theory
theory that 3 types of cones of blue, green, and red that when mixed and fired at a certain speed determine the vision that is shown on the retina
afterimage
images that occur when a visual sensation persists for a brief time even after the original stimulus is removed
opponent-process theory
- paired colors of red-green and blue-yellow that are stimulated by 1 color and inhibited by the light of another color- it also accounts for afterimages
hertz
- measure of frequency- for hearing
pinna
-visible ear -entrance into the ear
auditory canal
short tunnel that runs from the pinna to the eardrum
cochlea
snail shaped structure in the inner ear filled with fluid whose vibrations cause organ of corti's hairs to vibrate thus producing a neural message
auditory nerve
hearing neural messages sending place in which axons reside
pitch
sounds that correspond to the frequency
place theory
- theory of pitch that states that different pitches are caused by the stimulation of hair cells in different locations on the organ of corti- for more than 4000 hz; high pitch means that hair cells near the oval window were stimulated
frequency theory
- pitch theory that states that pitch is determined by how strong the vibrations of the basilar membrane- good for low pitches
volley principle
theory of pitch that states that frequencies from 400-4000 causes hair cells (auditory nerve) to take turns in firing
gustation
another name for the sense of taste
taste buds
taste receptor cells
olfaction
ability to smell odors
olfactory bulbs
area in brain above nose and under frontal lobe that receive information from the taste buds/smelling receptor cells
somesthetic senses
body senses made of skin senses, kinesthetic senses, and vestibular senses
skin senses
sensation of touch, pressure, temperature, and pain
kinesthesia
the awareness of body movement
Proprioception
awareness of where the body and body parts are located in relation to each other in space, and to the ground
kinesthetic sense
- sense of body parts located in relation to the ground and each other- inform about contracting, stretching, joints and muscles
vestibular sense
sensations of movement, balance, and body position in inner ear; spinning and stopping-->you become dizzy
gate control theory
pain-release of substance p-stimulates other neurons that open spinal chord gates-carried to brain to activate cells in thalamus and lobes-brain interprets and sends signals that open gates more allowing more pain or closes them thus relieving pain
sensory conflict theory
motion sickness theory in which the information from the eyes conflicts with the information in vestibular senses resulting in nausea, dizziness, etc
otolith organs
fluid sacs above the cochlea that tell the person in what direction they are moving
perception
ability of the brain to take in and interpret all senses to present a message to us
size constancy
tendency to interpret an object as always being the same size, regardless of its distance
shape constancy
tendency to interpret the shape of an object being the same even when its shape changes on the retina
brightness constancy
tendency to perceive the brightness of an object as the same even when the light conditions change
figure-ground
tendency to perceive objects or figures as existing on a background ex: goblet and two faces
reversible figures
illusion in which figure and ground can be reversed ex: goblet and two faces
proximity
tendency to group things that are near each other ex: ****
similarity
tendency to group things together that look similar to each other ex: team members with the same clothes
closure
tendency to complete incomplete figures
continuity
tendency to perceive things as continuous pattern rather than complex, broken-up pattern
contiguity
tendency to perceive two things that happen close together in time as being related
depth perception
ability to see the world in three dimensions
monocular cues
perceiving depth form one eye only; pictorial depth cues
linear perspective
tendency for parallel line to seem like they are converging on each other
relative size
perception that occurs when objects that a person expects to be a certain size seem smaller because they are assumed to be farther away
overlap
aka interposition; assumption that object that appears to be blocking part of another object is in front of that object
binocular cues
cues for perceiving depth based on both eyes
aerial perspective
haziness that surrounds objects that are far away, causing the distance to be greater
texture gradiant
texture becomes smaller and fine as the distance increases
motion parallax
perception of being in a car and things like trees move very fast but the mountains in the back move slowly
accommodation
brain's use of information about objects being far/close by the changing thickness of the lens
convergence
crossing eyes for objects nearest the eye and not so much for father objects
binocular disparity
objects closer to the eyes seem to jump around when closing one eye and then the other. objects farther away don't do that
muller lyer illusion
illusion of line length that is distorted by inward-turning or outward-turning corners on the ends of the line, causing lines of equal length to appear to be different
perceptual set
tendency to perceive things a different way because of past experiences or expectations. what you see expects on what you want to see
top-down processing
using pre-existing knowledge to organize feature into a unified whole. easier to put together a jigsaw puzzle if you see a picture before
bottom-up processing
analysis of smaller features to build up to complete perception. ex: making jigsaw puzzle from no picture
nervous system
an extensive network of specialized cells that carries information to and from all parts of the body
neuroscience
a branch of the life sciences that deals with the structure and function of neurons, nerves, and nervous tissue
biological psychology (behavioral neuroscience)
branch of neuroscience that focuses on the biological bases of psychological processes, behavior, and learning
neuron
the basic cell that makes up the nervous system and that receives and sends messages within that system
dendrites
branchlike structures that receive messages from other neurons
soma
the cell body of the neuron responsible for maintaining the life of the cell
axon
tubelike structure that carries the neural message to other cells
glial cells
cells that provide support for the neurons to grow on and around, deliver nutrients to neurons, produce myelin to coat axons, clean up waste products and dead neurons, influence information processing, and, during prenatal development, influence the generation of new neurons
myelin
fatty substances produced by certain glial cells that coat the axons of neurons to insulate, protect, and speed up the neural impulse
nerves
bundles of axons coated in myelin that travel together through the body
diffusion
process of molecules moving from areas of high concentration to area of low concentration
resting potential
the state of the neuron when not firing a neural impulse
action potential
the release of the neural impulse consisting of a reversal of the electrical charge within the axon
all-or-none
referring to the fact that a neuron either fires completely or does not fire at all
synaptic knob
rounded areas on the end of the axon terminals
axon terminals
branches at the end of the axon
synaptic vesicles
saclike structures found inside the synaptic knob containing chemicals
neurotransmitter
chemical found in the synaptic vesicles that, when released, has an effect on the next cell
synapse (synaptic gap)
microscopic fluid-filled space between the synaptic knob of one cell and the dendrites or surface of the next cell
receptor sites
three-dimensional proteins on the surface of the dendrites or certain cells of the muscles and glands which are shaped to fit only certain neurotransmitters
excitatory synapse
synapse at which a neurotransmitter causes the receiving cell to fire
inhibitory synapse
synapse at which a neurotransmitter causes the receiving cell to stop firing
antagonists
chemical substances that block or reduce a cell's response to the action of other chemicals or neurotransmitters
agonists
chemical substances that mimic or enhance the effects of a neurotransmitter on the receptor sites of the next cell, increasing or decreasing the activity of that cell
reuptake
process by which neurotransmitters are taken back into the synaptic vesicles
enzymatic degradation
process by which structure of neurotransmitter is altered so it can no longer act on a receptor
central nervous system (CNS)
part of the nervous system consisting of the brain and spinal cord
spinal cord
a long bundle of neurons that carries messages between the body and the brain and is responsible for very fast, lifesaving reflexes
afferent (sensory) neuron
a neuron that carries information from the senses to the central nervous system
efferent (motor) neuron
a neuron that carries messages from the central nervous system to the muscles of the body
interneuron
a neuron found in the center of the spinal cord that receives information from the afferent neurons and sends commands to the muscles through the efferent neurons; interneurons also make up the bulk of the neurons in the brain
reflex arc
the connection of the afferent neurons to the interneurons to the efferent neurons, resulting in a reflex action
neuroplasticity
the ability within the brain to constantly change both the structure and function of many cells in response to experience or trauma
stem cells
special cells found in all the tissues of the body that are capable of manufacturing other cell types when those cells need to be replaced due to damage or wear and tear
peripheral nervous system (PNS)
all nerves and neurons that are not contained in the brain and spinal cord but that run through the body itself
somatic nervous system
division of the PNS consisting of nerves that carry information from the senses to the CNS and from the CNS to the voluntary muscles of the body
autonomic nervous system (ANS)
division of the PNS consisting of nerves that control all of the involuntary muscles, organs, and glands
sensory pathway
nerves coming the sensory organs to the CNS consisting of afferent neurons
motor pathway
nerves coming from the CNS to the voluntary muscles, consisting of efferent neurons
sympathetic division (fight-or-flight system)
part of the ANS that is responsible for reacting to stressful events and bodily arousal
parasympathetic division
part of the ANS that restores the body to normal functioning after arousal and is responsible for the day-to-day functioning of the organs and glands
endocrine glands
glands that secrete chemicals called hormones directly into the bloodstream
hormones
chemicals released into the bloodstream by endocrine glands
pituitary gland
gland located in the brain that secretes human growth hormone and influences all other hormone-secreting glands (also known as the master gland)
pineal gland
endocrine gland located near the base of the cerebrum; secretes melatonin
thyroid gland
endocrine gland found in the neck; regulates metabolism
pancreas
endocrine gland; controls the levels of sugar in the blood
gonads
sex glands; secrete hormones that regulate sexual development and behavior as well as reproduction
ovaries
the female gonads
testes
the male gonads
adrenal glands
endocrine glands located on top of each kidney that secrete over 30 different hormones to deal with stress, regulate salt intake, and provide a secondary source of sex hormones affecting the sexual changes that occur during adolescence
deep lesioning
insertion of a thin, insulated wire into the brain through which an electrical current is sent that destroys the brain cells at the tip of the wire
computed tomography (CT)
brain-imaging method using computer-controlled X-rays of the brain
magnetic resonance imaging (MRI)
brain-imaging method using radio waves and magnetic fields of the body to produce detailed images of the brain
electroencephalograph
machine designed to record the electroencephalogram
electroencephalogram (EEG)
a recording of the electrical activity of large groups of cortical neurons just below the skull, most often using scalp electrodes
positron emission tomography (PET)
brain-imaging method in which a radioactive sugar is injected into a person and a computer compiles a color-coded image of the activity of the brain
single photon emission computed tomography (SPECT)
neuroimaging method that is similar to PET but uses a different radioactive tracer and can be used to examine brain blood flow
functional magnetic resonance imaging (fMRI)
MRI-based brain-imaging method that allows for functional examination of brain areas through changes in brain oxygenation
medulla
the first large swelling at the top of the spinal cord, forming the lowest part of the brain, which is responsible for life-sustaining functions such as breathing, swallowing, and heart rate
pons
the larger swelling above the medulla that connects the top of the brain to the bottom and that plays a part in sleep, dreaming, left-right body coordination, and arousal
reticular formation (RF)
an area of neurons running through the middle of the medulla and the pons and slightly beyond that is responsible for general attention, alertness, and arousal
cerebellum
part of the lower brain located behind the pons that controls and coordinates involuntary, rapid, fine motor movement
limbic system
a group of several brain structures located primarily under the cortex and involved in learning, emotion, memory, and motivation
thalamus
part of the limbic system located in the center of the brain, this structure relays sensory information from the lower part of the brain to the proper areas of the cortex and processes some sensory information before sending it to its proper area
olfactory bulbs
two projections just under the front of the brain that receive information from the receptors in the nose located just below
hypothalamus
small structure in the brain located below the thalamus and directly above the pituitary gland, responsible for motivational behavior such as sleep, hunger, thirst, and sex
hippocampus
curved structure located within each temporal lobe, responsible for the formation of long-term memories and the storage of memory for location of objects
amygdala
brain structure located near the hippocampus, responsible for fear responses and memory of fear
cortex
outermost covering of the brain consisting of densely packed neurons, responsible for higher thought processes and interpretation of sensory input
cerebral hemispheres
the two sections of the cortex on the left and right sides of the brain
corpus callosum
thick band of neurons that connects the right and left cerebral hemispheres
occipital lobe
section of the brain located at the rear and bottom of each cerebral hemisphere containing the visual centers of the brain
parietal lobes
sections of the brain located at the top and back of each cerebral hemisphere containing the centers for touch, taste, and temperature sensations
somatosensory cortex
are of neurons running down the front of the parietal lobes responsible for processing information from the skin and internal body receptors for touch, temperature, body position, and possibly taste
temporal lobes
areas of the brain located along the side, starting just behind the temples, containing the neurons responsible for the sense of hearing and meaningful speech
frontal lobes
areas of the brain located in the front and top, responsible for higher mental processes and decision making as well as the production of fluent speech
motor cortex
rear section of the frontal lobe, responsible for sending motor commands to the muscles of the somatic nervous system
mirror neurons
neurons that fire when an animal or person performs an action and also when an animal or person observes that same action being performed by another
association areas
areas within each lobe of the cortex responsible for the coordination and interpretation of information, as well as higher mental processing
Broca's aphasia
condition resulting from damage to Broca's area, causing the affected person to be unable to speak fluently, to mispronounce words, and to speak haltingly
Wernicke's aphasia
condition resulting from damage to Wernicke's area, causing the affected person to be unable to understand or produce meaningful language
unilateral spatial neglect
condition produced most often by damage to the parietal lobe association areas of the right hemisphere resulting in an inability to recognize objects or body parts in the left visual field
cerebrum
the upper part of the brain consisting of the two hemispheres and the structures that connect them
psychology
the scientific study of behavior and mental processes
objective introspection
the process of examining and measuring one's own thoughts and mental activities
structuralism
early perspective in psychology associated with Wilhelm Wundt and Edward Titchener, in which the focus of study is the structure or basic elements of the mind
functionalism
early perspective in psychology associated with William James, in which the focus of study is how the mind allows people to adapt, live, work, and play
Gestalt psychology
early perspective in psychology focusing on perception and sensation, particularly the perception of patterns and whole figures
psychoanalysis
the theory and therapy based on the work of Sigmund Freud
behaviorism
the science of behavior that focuses on observable behavior only
psychodynamic perspective
modern version of psychoanalysis that is more focused on the development of a sense of self and the discovery of other motivations behind a person's behavior than sexual motivations
cognitive perspective
modern perspective that focuses on memory, intelligence, perception, problem solving, and learning
cognitive neuroscience
study of the physical changes in the brain and nervous system during thinking
sociocultural perspective
perspective that focuses on the relationship between social behavior and culture
biopsychological perspective
perspective that attributes human and animal behavior to biological events occurring in the body, such as genetic influences, hormones, and the activity of the nervous system
evolutionary perspective
perspective that focuses on the biological bases of universal mental characteristics that all humans share
psychologist
a professional with an academic degree and specialized training in one or more areas of psychology
psychiatrist
a medical doctor who has specialized in the diagnosis and treatment of psychological disorders
psychiatric social worker
a social worker with some training in therapy methods who focuses on the environmental conditions that can have an impact on mental disorders, such as poverty, overcrowding, stress and drug abuse
scientific method
system of gathering data so that bias and error in measurement are reduced
hypothesis
tentative explanation of a phenomenon based on observations
replication in research
repetition of a study or experiment to see if the same results will be obtained in an effort to demonstrate reliability of results
observer effect
tendency of people or animals to behave differently from normal when they know they are being observed
participant observation
a naturalistic observation in which the observer becomes a participant in the group being observed
observer bias
tendency of observers to see what they expect to see
case study
study of one individual in great detail
representative sample
randomly selected sample of subjects from a larger population of subjects
population
the entire group of people or animals in which the researcher is interested
correlation
a measure of the relationship between two variables
correlation coefficient
a number derived from the formula for measuring a correlation and indicating the strength and direction of a correlation
experiment
a deliberate manipulation of a variable to see if corresponding changes in behavior result, allowing the determination of cause-and-effect relationships
operational definition
definition of a variable of interest that allows it to be directly measured
independent variable
variable in an experiment that is manipulated by the experimenter
dependent variable
variable in an experiment that represents the measurable response or behavior of the subjects in the experiment
experimental group
subjects in an experiment who are subjected to the independent variable
control group
subjects in an experiment who are not subjected to the independent variable and who may receive a placebo treatment
random assignment
process of assigning subjects to the experimental or control group randomly, so that each subject has an equal chance of being in either group
placebo effect
the phenomenon in which the expectations of the participants in a study can influence their behavior
experimenter effect
tendency of the experimenter's expectations for a study to unintentionally influence the results of the study
single-blind study
study in which the subjects do not know if they are in the experimental or the control group
double-blind study
study in which neither the experimenter nor the subjects know if the subjects are in the experimental or control group
critical thinking
making reasoned judgments about claims