absolute threshold
The lowest amount of stimulation needed to detect a particular stimulus 50 percent of the time.
accommodation (development)
In Jean Piaget’s theory, the act of altering a previously existing schema in response to new information. accommodation (vision)
The process in which the lens of the eye changes shape in response to external conditions so that an object remains in focus.
achievement motivation
A desire for accomplishment and mastery.
action potential
A neural impulse. A brief electrical charge that travels down an axon when it fires.
activation-synthesis hypothesis
The hypothesis that explains dreams as the brain’s attempt to make sense of random firings in the pons area of the brain.
adaptation
The process by which the eye adjusts to varying levels of light or colors.
adrenal glands
Small glands that produce steroid hormones, adrenaline, and noradrenaline, which help control heart rate, blood pressure, and other important bodily functions. There are two adrenal glands, one located on top of each kidney.
algorithm
A step-by-step method for solving a problem that guarantees a solution but may take too long to implement in some situations.
all-or-none law
This law states that the process by which a neuron fires is all or none. Either a neuron receives sufficient
stimulation from surrounding cells to fire, or it doesn’t. There is no variation in the size of the electrical impulse once the neuron fires.
alpha waves
Brain waves on an electroencephalogram (EEG) that are associated with being awake and quiet.
amnesia
Loss of memory.
amphetamines
A stimulant to the central nervous system that increases energy and decreases appetite; used to treat narcolepsy and some forms of depression.
amplitude (loudness)
The height of the sound waves generated by an auditory stimulus.
amygdala
A portion of the limbic system of the brain that is linked to emotions and forming long-term memories. antidepressant
One of a class of medications that is used to treat the symptoms of mood and anxiety disorders. Examples of antidepressant medications include selective serotonin reuptake inhibitors (SSRIs), such as Prozac or Zoloft.
antidepressant
A drug used to treat depression. Most work by increasing certain neurotransmitters, such as serotonin. antisocial personality disorder
A personality disorder in which the individual (usually male) exhibits a lack of conscience for wrongdoing, even toward friends or family. His behavior can be aggressive and ruthless.
anxiety disorder
A disorder characterized by unusually high levels of anxiety that interfere with one’s functioning. Anxiety
disorders include generalized anxiety disorder, specific phobias, social anxiety disorder, and panic disorder.
anxiety disorders
A group of disorders characterized by unusually high levels of anxiety that interfere with one’s functioning. Anxiety disorders include generalized anxiety disorder, specific phobias, social anxiety disorder, and panic disorder.
apnea
A sleep disorder in which the individual stops breathing multiple times during the night.
applied research
Research that is conducted to solve a specific or practical problem.
Asch’s conformity studies
Solomon Asch’s experiments with lines showed that many people will go along with the majority, even if they know the majority’s answer is incorrect.
Asperger disorder
A developmental disorder associated with deficits in social skills and transitions, and a preference for
sameness or predictable events. This is a separate disorder under the category of autism spectrum disorder. assessment
A method of obtaining information about a person’s intellectual function or personality characteristics using any combination of interviews, questionnaires, specialized instruments, and observations.
assimilation
In Jean Piaget’s theory, incorporating new information and experiences in terms of existing schemas. association areas
Portions of the cerebral cortex that integrate material from many parts of the brain. These areas are
responsible for higher brain functions such as remembering, learning, and interpreting sensory information.
attachment
A strong and enduring emotional bond between an infant or young animal and its caregiver or parent.
attention-deficit/hyperactivity disorder (ADHD)
A disorder that is characterized by overactivity, impulsivity, and an inability to sustain attention. The onset of this disorder is usually in childhood, but it may be diagnosed in adolescence or adulthood as well. Fewer
symptoms are required for diagnosis after age 16.
attitude
A disposition toward a particular situation or object. Attitudes typically have cognitive, behavioral, and affective (emotional) components.
authoritarian
One of Diana Baumrind’s styles of parenting, characterized by a low amount of responsiveness and a high amount of control.
authoritative
One of Diana Baumrind’s styles of parenting, characterized by a high amount of responsiveness and moderate amount of control. Authoritative parenting is associated with better child adjustment than the other three
parenting styles (authoritarian, permissive, and uninvolved).
autism
A severe neurologically based developmental disorder where one shows impaired social interactions, problems with verbal and nonverbal communication, repetitive behavior, and narrow interests.
autonomic nervous system
The portion of the nervous system that controls glands and muscles of the internal organs. availability heuristic
Estimating how likely an event is based on how available the event is in one’s memory.
axon
A long, hair-like extension of a nerve cell (a neuron) that transmits electrical impulses away from the cell body. basic research
Research that is conducted for the sake of knowledge itself, rather than to solve a specific or practical problem.
behavior genetics
The branch of genetics that examines the genetic and environmental contributions to personality characteristics and behavior.
behaviorism
A theoretical perspective that focuses on observable, quantifiable behavior and the relationships between behavior and environmental variables.
bell curve
Also called the normal curve. Many traits, including intellectual abilities, are said to be normally distributed,
with roughly 68 percent of the distribution being within one standard deviation of the mean, and more than 90 percent being within two standard deviations of the mean.
beta waves
Brain waves on an electroencephalogram (EEG) that are associated with conscious mental activity.
Big Five Theory (OCEAN)
A trait theory of personality that holds that personality is composed of five dimensions: openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism.
binocular cue
A visual depth cue that requires the use of both eyes.
biomedical approach
An approach that studies biological processes in order to understand psychological disorders, often pointing to genetic predisposition as the cause of a disorder. Surgical procedures and drug therapies are used to help
treat psychological disorders through this approach.
biopsychosocial approach
An integrated viewpoint that incorporates the analyses of biological, psychological, and social-cultural factors and offers a more complete picture of behaviors or mental processes.
bipolar disorder
A mood disorder characterized by manic episodes followed by episodes of depression.
bipolar disorders
A group of disorders characterized by manic episodes followed by episodes of depression.
blind spot
An area or direction in which a person’s vision is obscured because no receptor cells are located there.
blocking
An interruption in the flow of thought.
blood-brain barrier
The protective barrier, composed of glia, that keeps certain substances in the blood from reaching brain tissue. brain stem
The portion of the brain that connects the upper brain with the spinal cord. The brain stem is responsible for life-sustaining functions such as heartbeat and respiration, as well as maintaining alertness.
bystander effect
The effect that a person is less likely to assist in an emergency when he or she is among a group of bystanders than when he or she is a lone bystander.
Cannon-Bard theory of emotion
A theory that states that the physiological sensations of an emotion and the psychological experience of an emotion happen simultaneously. Neither one causes the other.
case study
An in-depth study of a single person who has unusual characteristics. Case studies are often useful when a condition or characteristic is so rare that group experiments are not feasible.
CAT (Computerized Axial Tomography)
A computerized series of X-rays taken from different angles that are compiled to create an image of the area in question.
central fissure
A long, deep fissure on the lateral surface of the cerebral cortex.
central nervous system
The portion of the nervous system consisting of the brain and spinal cord.
central tendency
A general term for the midpoint, or center, of a distribution. Central tendency can be measured through the mean, median, or mode.
cerebellum
The portion of the hindbrain that helps to control posture, balance, and motor coordination.
cerebral cortex
The outer layer of nerve cells covering the cerebrum that is responsible for most higher cognitive functions. cerebral hemispheres
The right and left halves of the cerebrum.
chromosomes
Structures made of deoxyribonucleic acid (DNA) that contain genes. Chromosomes are located in the nucleus of a cell. Humans normally have 23 pairs of chromosomes, or a total of 46.
chunking
A strategy to increase memory in which smaller bits of information are grouped into meaningful units. circadian rhythm
A metabolic and behavioral cycle that is aided by light cues. It repeats about every 24 hours in humans.
classical conditioning
Originally discovered by Ivan Pavlov, classical conditioning is a form of learning in which a subject learns an association between two stimuli. First, a stimulus (the unconditioned stimulus) produces an automatic,
unlearned response (the unconditioned response). The unconditioned stimulus is then paired with a neutral stimulus (the conditioned stimulus) until the subject learns the association between the two stimuli, and the subject responds (the conditioned response) to the conditioned stimulus presented alone.
clinical
The branch of psychology that deals with the diagnosis and treatment of psychological disorders. cochlea
The snail-shaped, fluid-filled organ in the inner ear that contains the basilar membrane.
cognitive behavior therapy
A therapy that combines changing self-defeating beliefs and behavioral therapy.
cognitive dissonance
The theory that we act to reduce the discomfort (dissonance) we feel when two of our actions or ideas are in conflict.
cognitive map
A mental representation of a spatial layout. For example, you might have a cognitive map of your school that allows you to remember where your locker is.
cognitive perspective
The branch of psychology that deals with thought processes such as memory and language.
concrete operations
The stage in Jean Piaget’s theory that lasts from ages 7 to 11. In this stage, children can use logical reasoning about concrete objects, but they lack the capacity for abstract thought.
conditioned response (CR)
In classical conditioning, the response that has to be learned, as opposed to the unconditioned response (UCR), which occurs naturally without having to learn it.
conditioned stimulus (CS)
In classical conditioning, the neutral stimulus that is paired with the unconditioned stimulus (UCS) to provoke the conditioned response.
conduction deafness
Hearing loss related to problems with the ossicles, the bones of the middle ear.
cones
The visual receptors in the retina that are responsible for color vision, but are less useful for seeing in low-light conditions.
confabulation
An imagined but plausible memory that fills in gaps about what a person actually remembers. conformity
The process of adjusting one’s attitudes or behavior to fit with others or to meet a group standard.
confounding variable
In an experiment, any variable other than the independent variable that creates differences between the experimental and control groups.
conservation
According to Jean Piaget’s theory, the principle that properties such as mass and volume remain the same even if their form changes.
continuous reinforcement schedule
A reinforcement schedule in which every instance of the target behavior is reinforced.
control group
In an experiment, the group that does not receive the experimental treatment but is identical to that group in all other respects. Results from the experimental group are typically compared to those of the control group.
conventional morality
Lawrence Kohlberg’s second level of moral reasoning, in which moral decisions tend to be made on the basis of social norms or laws.
convergence
A binocular cue that perceives depth; the eyes converge inward when looking at an object.
cornea
The clear part of the eye that lies in front of the iris and is part of the eye’s protective covering. corpus callosum
The bundle of nerve fibers that connects the left and right hemispheres of the brain.
correlation
The degree of relatedness between two sets of data.
crystallized intelligence
Mental ability that includes material learned over the entire life span, such as vocabulary and general knowledge of the world.
data
Information gathered in the course of scientific study.
decay
A theory of forgetting in which items are lost from memory because of the passage of time.
declarative memory
The portion of long-term memory that involves memory for facts and events. Declarative memory is further divided into semantic and episodic memory.
defense mechanisms
In Sigmund Freud’s theory, defense mechanisms distort reality when the ego is threatened by anxiety.
Defense mechanisms include repression, projection, and many others.
deindividuation
Loss of self-awareness and self-restraint in group social situations.
deinstitutionalization movement
The movement (begun in the late 1960s and early 1970s) in which people with serious mental disorders, such as schizophrenia, were discharged from psychiatric hospitals and managed in the community on an outpatient basis.
delta waves
Large, slow brain waves on an electroencephalogram (EEG) that are associated with deep sleep. delusions
False beliefs that occur in serious psychological disorders such as schizophrenia.
dendrites
The bushy ends of a neuron that pick up information from neighboring cells and transmit it to the cell body. dependent variable
In an experiment, the variable that is measured to determine whether the independent variable had an effect. depolarize
To make the cell membrane charge less negative. If the cell membrane is sufficiently depolarized, the neuron will fire.
depression
A mood disorder characterized by persistent sad mood, eating and sleeping disturbances, motor disturbances (either lethargy or agitation), difficulty concentrating, and feelings of hopelessness or worthlessness.
depressive disorders
A group of disorders characterized by a persistent sad mood, eating and sleeping disturbances, motor
disturbances (either lethargy or agitation), difficulty concentrating, and feelings of hopelessness or
worthlessness. Depressive disorders include major depressive disorder and disruptive mood dysregulation disorder.
depth perception
The ability to visually perceive the world and to understand spatial relationships in order to gauge the distances between objects.
descriptive statistics
Statistics that provide information about the features of a particular sample.
desensitization
An example of a counterconditioning process. For example, someone who responds to heights with fear might be desensitized by pairing the experience of heights with something that promotes a relaxation response.
diffusion of responsibility
A phenomenon in which a person feels less responsibility to assist in an emergency situation if there are
others around with whom to “share” that responsibility. It is suggested that this is the reason for the bystander effect.
discrimination (learning)
The cognitive process whereby two or more stimuli are distinguished.
discrimination (race relations)
Unjustifiable negative behavior toward another group or its members.
display rules
Culturally based rules about the outward display of emotion.
dissociative disorders
A group of disorders in which the sense of self becomes separated (dissociated) from previous thoughts or memories. Dissociative disorders include dissociative amnesia, dissociative fugue, and dissociative identity disorder.
dissociative fugue
A dissociative disorder in which one unexpectedly travels to a new location and is unable to remember his or her past.
DNA (deoxyribonucleic acid)
The substance inside a cell’s nucleus that contains instructions for all of the structures and processes that the body needs to function.
dominant
An allele whose genetic instructions are followed regardless of the other alleles present. If there is a dominant allele in the gene pair, the instructions of the dominant allele will be followed.
double blind
A research design in which participants are given either the experimental treatment or a placebo, and neither the participants nor those administering the treatments know which participants are receiving which condition. This is commonly done in drug studies.
Down’s syndrome
A form of retardation caused by an extra chromosome and characterized by certain facial features and lower- than-normal brain size and weight.
drive-reduction theory
Clark Hull’s theory of learning in which our drives, such as hunger or thirst, prompt our behavior, which causes a reduction in the drive. This reduction in the drive is reinforcing, which causes us to engage in the behavior more frequently.
eardrum
Another term for the tympanic membrane.
echoic memory
A momentary sensory memory of auditory stimuli, lasting two to three seconds.
ego
According to Sigmund Freud’s theory, the portion of the personality that mediates among the desires of the id, the moral control of the superego, and the demands of the environment. It is largely conscious and operates according to the reality principle.
egocentrism
Inability to see things from another’s perspective. According to Jean Piaget, children in the preoperational stage exhibited egocentrism in their thinking.
electrochemical
A process that is both electrical and chemical. Neuron transmission is electrochemical because there is an electrical process within the neuron, but there is a chemical process that takes place in the synapse, or the gap between neurons.
emotion
An internal subjective state of feeling and the bodily sensations that accompany that feeling. empirically derived
A test that was developed by testing items and selecting those that show differences between groups. The MMPI is an example.
encode
To transform incoming information so that it can be processed and stored in memory.
endocrine system
A system of glands that release hormones into the blood.
endorphins
Substances produced by the body that are involved in pain relief and positive mood.
epinephrine
A hormone secreted by the adrenal medulla that is stimulated by the central nervous system in response to stress or fear. It acts to increase heart rate, blood pressure, cardiac output, and carbohydrate metabolism.
episodic memory
The part of declarative memory that involves memory for specific events in one’s own life.
Erikson’s psychosocial stages
A theory of eight stages of social development throughout the lifespan. These include trust vs. mistrust, autonomy vs. doubt, initiative vs. guilt, competence vs. inferiority, identity vs. role confusion, intimacy vs. isolation, generativity vs. stagnation, and integrity vs. despair.
estrogen
A hormone that controls the menstrual cycles and development of female secondary sex characteristics. It is produced in the ovaries in women, and small amounts are produced in the testes in men.
ethics
In general, the scientific study of morality. In psychology, it refers to the codes of conduct for the profession, including research, teaching, and clinical work.
evolutionary perspective
The study of the evolution of behavior using the principles of natural selection.
excitatory
A substance that increases the likelihood a neuron will fire.
experiment
A research design that features random assignment of subjects to experimental and control groups, at least one independent variable that is manipulated, and at least one dependent variable that is measured. It is the only research design in which cause-and-effect relationships can legitimately be determined.
experimental condition or group
In an experiment, the group that is exposed to the independent variable.
extinction
In operant conditioning, the disappearance of a behavior due to a previously reinforced behavior no longer being reinforced.
extrinsic
Something that comes from an external source. A paycheck is an example of an extrinsic reward.
false memory syndrome
A condition in which a person has a memory for an event that either didn’t occur at all, or occurred in a manner much different from the person’s memory of it.
feature detection cells
Cells in the visual cortex of the brain that respond to different characteristics, or features, of a visual stimulus. feature detection theory
An explanation for pattern recognition; the theory that we process images in terms of their constituent parts and then match the features of a pattern to those features stored in memory.
figure and ground
An aspect of perception where the perceived is separated into at least two parts, each with different attributes, but influencing one another.
fixed schedule of reinforcement
A schedule in which reinforcement occurs after a consistent, or fixed number of responses (fixed ratio), or after a consistent amount of time (fixed interval).
fluid intelligence
The intellectual ability that involves succeeding in new tasks or taking previous knowledge and applying it in a new way.
Flynn effect
The trend that IQ scores tend to rise by an average of three points per decade, although different areas of the world vary in the magnitude of the gains.
forced choice
A method of item construction on a questionnaire in which the respondent is required to choose one among a group of alternatives.
forebrain
The largest and most recently evolved division of the brain. It contains the cerebral cortex, the basal ganglia, the thalamus, and the hypothalamus.
formal operations
Jean Piaget’s fourth stage of cognitive development, from 11 years of age through the life span. The formal operations stage involves the capability for abstract thought, and the application of logical reasoning
processes to abstract ideas.
fovea
A depression near the center of the retina that is densely packed with cones. The fovea is where vision is most acute.
frequency theory
A theory that sound is heard when pulses travel up the auditory nerve and carry the information to the brain for processing, and that the rate of this pulse exactly matches the frequency of whatever tone is heard.
functional fixedness
The tendency to think about and use objects only in their customary way.
functionalism
A movement in psychology led by William James in which consciousness was studied according to the functions it serves, rather than its structures.
fundamental attribution error
The tendency to attribute the behavior of others to internal dispositions, and to attribute one’s own behavior to external dispositions.
g factor
The general intelligence factor. Proposed by Charles Spearman, who argued that a basic ability underlies the performance of different intellectual tasks.
GABA
The main inhibitory receptor in the central nervous system.
gate control theory
The theory of pain perception that suggests there is a spinal “gate” that can be closed by signals from the brain. Closing the gate keeps pain signals from reaching the brain.
gender identity
Our sense of being male or female.
gender role
The behaviors and attitudes expected of people because they are male or female.
gene
A segment of DNA located at a specific site on a chromosome. Genes contain instructions, or “blueprints,” for the synthesis of proteins that make up all of the necessary structures and functions of the body.
general adaptation syndrome
First described by Hans Selye, this is the name given to the three stages of physiological responses to prolonged stress: alarm, resistance, and exhaustion.
generalization
The transfer of a response learned from one stimulus to a similar stimulus.
generalized anxiety disorder
An anxiety disorder characterized by worry and acute but time-limited symptoms. It is accompanied by nervousness and elevated blood pressure.
genotype
An individual’s entire set of genes. This is differentiated from phenotype, which is the outward expression of the genotype.
Gestalt
A school of psychology that believes individuals perceive objects and patterns as whole units and that the whole is more than the sum of its parts. They believed that behavior, perception, and all elements of the self must be viewed as a whole.
glial cells
Cells that surround neurons, providing support and insulation.
group polarization
The enhancement of a group’s tendencies; if a group is tolerant and discusses those ideas, it is likely to
become more tolerant. Conversely, if a group is racist and discusses it, it is more likely to become more racist. groupthink
This occurs when a desire for harmony in a group overrides looking at other alternatives or possibilities.
gustation
The sense of taste.
hallucinations
False perceptions, usually auditory, that are often present in schizophrenia.
Harry Harlow
Harlow did experiments on forming attachment, where monkeys would rather go to a cloth mother than a wire mother that provided nourishment.
hemisphere
The left or right half of the brain.
heritability
The degree to which variability in a characteristic, such as intellectual ability or a personality trait, can be explained by heredity.
heuristic
A strategy for solving a problem or coming to a decision that might be efficient, but doesn’t guarantee the right decision.
hierarchy of needs
Developed by Abraham Maslow, a pyramid model in which basic needs, such as safety, food, and sleep, must be satisfied before the person can aspire to higher-level needs, such as belonging and self-esteem.
hindbrain
The hindbrain is the portion of the brain that is responsible for many basic life-support functions such as the coordination of motor activity, posture, equilibrium, and sleep patterns. It also helps regulate breathing and blood circulation.
hippocampus
A portion of the brain located inside the temporal lobes. It is part of the limbic system and is involved in learning and formation of long-term memories.
hoarding disorder
An obsessive-compulsive–related disorder new to the DSM-5 that is characterized by a persistent difficulty in discarding or parting with possessions, regardless of the value others may attribute to these possessions.
homeostasis
Maintaining a consistent balance, or equilibrium.
hormone
A substance that is released by the endocrine glands and travels through the blood to influence other glands and organs.
humanistic approach
An approach in psychology that is characterized by a deep concern for human beings, their dignity, and their universal struggles, and which uses unconditional positive regard to help clients overcome obstacles.
Abraham Maslow and Carl Rogers were two key figures in developing this approach.
humanistic movement
A movement in psychology that was characterized by a deep concern for human beings, their dignity, and their universal struggles. Abraham Maslow and Carl Rogers were two key figures in this movement.
hypothalamus
A region of the brain beneath the thalamus in the forebrain. It is involved in the regulation of hunger, thirst, sex drive, body temperature, and other states. It also secretes hormones that stimulate the pituitary gland, the
“master gland” of the endocrine system.
hypothesis
A prediction about the relationships between two or more variables.
iconic memory
A momentary sensual memory of visual stimuli, lasting several tenths of a second.
id
In Sigmund Freud’s theory, the portion of the personality that contains our instincts and our irrational desires. It is largely unconscious and very demanding. It lives according to the pleasure principle, which is to maximize pleasure and minimize pain.
implicit memory
The portion of long-term memory that deals with remembering procedures, such as driving a car or playing the trombone. It is also known as procedural memory.
imprinting
Quick learning that occurs within a sensitive period of the organism’s development and without obvious reinforcement for the learned behavior.
incentive
A benefit that is offered to encourage a specific behavior. The incentive theory of motivation holds that motivation is governed by incentives.
independent variable
The variable in an experiment that is manipulated by the experimenter to determine whether it has an effect on the dependent variable.
induced motion
An optical illusion in which a stationary object appears to move in one direction because of the movement of objects on either side of it in the opposite direction.
informed consent
A procedure in which a potential research participant is fully informed of all the risks and benefits of participating in the study before consenting to do so.
inhibitory
A substance that decreases the likelihood a neuron will fire.
insight
When a subject develops a sudden realization about the solution to a problem and applies that realization to similar problems.
insomnia
Inability to sleep, which could be characterized by difficulty falling asleep, staying asleep, and/or awakening too early.
instinct
An inborn, rather than learned, tendency toward a particular behavior.
intelligence
General mental ability; the ability to acquire information and to apply that information in order to understand the world.
interference
A process in which memory for certain information disrupts memory for other information. Interference can be proactive, when previously learned information disrupts the ability to learn later information; or it can be
retroactive, when learning new information makes it harder to remember old information.
interneuron
A neuron that connects a sensory and a motor neuron.
IQ
A numerical index of intelligence as measured by any of a number of intelligence tests. IQ scores generally have a mean of 100 and a standard deviation of 15.
iris
The colored portion of the eye that controls how much light enters the pupil.
James-Lange theory of emotion
The theory that our experience of emotion depends on our awareness of our psychological responses.
kinesthetic
The sense of body position. Also known as proprioception.
latent learning
A situation in which learning has occurred, but it is not used until there is an incentive to show the learning. law of effect
Proposed by Edward Thorndike, the law of effect states that a behavior is likely to be repeated when it maximizes pleasure and/or minimizes pain.
lens
The portion of the eye that changes shape in order to focus the visual image onto the retina. light adaptation
The changes that occur in the eye to permit vision when moving from darkness to light.
limbic system
A group of brain structures that are involved with emotions, the autonomic nervous system, and olfactory processing.
linguistic relativity
A theory of language that states that one’s language shapes one’s view of reality.
Little Albert
The little boy who was conditioned by John Watson and Rosalie Raynor to be afraid of a white rat. Watson and Raynor used classical conditioning to pair the rat with a loud noise, until Little Albert began to exhibit fear in
response to the rat.
locus of control
The perception one has about what controls his or her life. A person with an external locus of control feels that
his fate is controlled by external circumstances. A person with an internal locus of control feels that he has control over his fate.
long-term memory
Virtually limitless, virtually permanent memory storage.
long-term potentiation
The biological basis of learning and memory, it is an increase in a synapse’s firing ability after a sequence of neurons is connected with a memory or learning.
major depressive disorder
A mood disorder, lasting weeks or months, in which a person his diminished interest in activities and a lack of energy.
mean
The arithmetic average of all of the scores in a distribution.
median
The middlemost score in a distribution.
medulla
The portion of the brain stem that is associated with life-sustaining functions such as heartbeat and respiration.
melatonin
A hormone produced by the pineal gland that is associated with sleep onset.
mere exposure effect
Repeated exposure to a novel stimuli increases the liking of that stimuli.
methamphetamines
A highly psychologically addictive, illicit, synthetic stimulant that induces feelings of euphoria. In pure form, it is a colorless crystalline solid, sold on the streets as glass, ice, or crystal. As a less pure form, it’s sold as
crystalline powder referred to as crank or speed, or in rock formation as tweak, dope, or raw.
microexpression
A brief and involuntary facial expression that shows a reaction to emotions a person is experiencing. midbrain
The area between the forebrain and the hindbrain, it primarily serves as a relay station for information.
Milgram’s obedience study
An experiment in which Stanley Milgram found that people will usually obey an authority, even if they might think what they are doing is wrong.
MMPI-2 (Minnesota Multiphasic Personality Inventory-2)
An objectively scored personality inventory that assesses psychopathology in several areas, such as anxiety and depression. The most widely used personality inventory.
mnemonic strategies
Strategies that are used to improve memory, such as the method of loci.
mode
The most frequent score in a distribution.
monocular cue
A visual depth cue that makes use of only one eye.
moral reasoning
The process by which people make moral decisions and judgments.
motivation
An internal state that activates goal-directed behavior.
motor neurons
Neurons that carry information from the brain and spinal cord to the muscles and glands.
MRI/fMRI (Functional Magnetic Resonance Imaging)
A neuroimaging technique that uses a magnetic field and radio waves to create images of the body without the use of radiation.
multiple intelligences
A theory of intellectual functioning proposed by Howard Gardner, who suggested that individuals can
demonstrate abilities in a variety of areas, such as spatial reasoning, musical ability, verbal-linguistic ability, and other areas.
mutation
A permanent change in the genetic makeup of an organism.
myelin sheath
A fatty sheath that wraps around axons, it aids in the conduction of nerve impulses.
narcolepsy
A sleep disorder characterized by sudden attacks of REM sleep.
nature-nurture
A question, issue, or controversy about how much can be attributed to heredity (nature) and how much to the environment (nurture) in the development of a person; this includes personality, intelligence, abilities, and
mental health.
negative (inverse) correlation
A relationship between two variables in which the values of one variable increase as the values of the other variable decrease.
negative reinforcement
Anything that causes a behavior to increase by removing an adverse condition in response to the behavior, like taking aspirin to remove a headache.
neurocognitive theories of dreaming
A group of theories that suggest that dreams are a byproduct of neural firings made by the brain during the night, which are our brain’s attempts to make sense of those firings.
neuroleptic
An antipsychotic drug used to treat schizophrenia and other disorders.
neuron
A nerve cell.
neuroscience
The scientific study of the nervous system.
neurosis
In Sigmund Freud’s theory, neurosis is a disorder based upon an imbalance between the id, ego, and superego.
neurotransmitter
A chemical substance that is released by one neuron into the synapse, or gap between neurons, to influence the functioning of another neuron.
neutral stimulus
A stimulus that does not provoke any particular response. In classical conditioning, a neutral stimulus (NS) is paired with the unconditioned stimulus (UCS) until the organism learns the association between the two
stimuli. The neutral stimulus then becomes the conditioned stimulus (CS).
norepinephrine
A hormone secreted by the adrenal gland. It increases blood pressure and rate and the depth of breathing,
raises the level of blood sugar, and decreases the activity of the intestines. It is also the main neurotransmitter of sympathetic nerve endings supplying the major organs and skin.
object permanence
The understanding that objects and people exist even if they are not in our presence.
observational (social) learning
Learning through observing and imitating others.
observational research
A way to do research in which careful, systematic observation in a natural environment is the main tool for data collection.
obsessive-compulsive disorder
A disorder characterized by obsessions and compulsions. Obsessive-compulsive disorders include hoarding disorder.
occipital lobes
The lobes of the cerebral cortex located in the rear of the brain that are primarily responsible for processing visual information.
Oedipus complex
According to Sigmund Freud, a boy experiences this complex during the phallic stage, during which he
experiences sexual desire for his mother and wants to eliminate his father as a rival for his mother’s affection.
olfaction
The sense of smell.
operant conditioning
A type of conditioning in which the organism learns an association between a voluntary behavior and its consequences.
operational definition
A concrete definition of a variable for the purposes of a particular experiment.
opponent process theory
The theory that opposing retinal processes (red-green, black-white, yellow-blue) make color vision possible. optic nerve
The cranial nerve that carries the visual impulse out of the back of the eye and into the brain for further processing.
ovaries
The pair of organs in a woman’s body that produce eggs. Also the part of any female animal or plant that produces eggs or seeds.
overgeneralization
When one extends a rule where it doesn’t apply. For example, when children learn to speak, they often apply standard grammar rules to irregular words.
overjustification effect
Inadvertently reducing intrinsic motivation by introducing extrinsic incentives. For example, paying someone to do a task that used to be inherently enjoyable may cause a decrease in enjoyment on that task.
pancreas
A gland situated near the stomach that secretes a digestive fluid into the intestine and also secretes the hormone insulin.
panic disorder
A disorder that involves sudden periods of intense anxiety or terror, with accompanying physical symptoms such as increased heart rate.
parallel processing
A feature of the visual system in which many different processes are taking place simultaneously.
paranoid
Having unwarranted or irrational suspicions or distrust of others.
parasympathetic nervous system
The division of the autonomic nervous system that calms the body down.
parietal lobe
The lobe of the cerebral cortex that is responsible for processing the sense of touch.
partial reinforcement schedule
A schedule of reinforcement in which only certain instances of the desired behaviors are reinforced. Partial reinforcement schedules fall into four types: fixed ratio, fixed interval, variable ratio, and variable interval
schedules.
percentile
The percentage of scores in a distribution that are below a particular score.
perception
The process of organizing and interpreting sensory information.
peripheral nervous system
The portion of the nervous system that relays information between the central nervous system and the rest of the body.
permissive
One of Diana Baumrind’s styles of parenting, which is characterized by a high degree of responsiveness and a low degree of control.
person-situation debate
A controversy in the study of personality, regarding whether behavior is more due to internal personality characteristics or situational factors.
personality disorders
Disorders characterized by enduring and rigid patterns of behavior that interfere with normal social functioning. PET (Positron Emission Tomography)
A neuroimaging technique that monitors the utilization of glucose in different parts of the brain. This allows researchers to view parts of the brain as they work.
phenotype
The physical expression of the genetic instructions contained in the genotype.
phobia
An excessive or unrealistic fear of an object or situation that causes significant distress or impairment in functioning.
photoreceptors
The sense receptors for the visual system.
pineal gland
A small gland located between the hemispheres of the brain that secretes the hormone melatonin, which aids in the onset of sleep.
pitch (frequency)
The frequency of sound waves, which translates into the highness or lowness of a sound.
pituitary gland
A gland located at the base of the brain producing hormones that control other glands and affect metabolism, bone growth, and sexual maturity.
placebo
A treatment that resembles the experimental condition, but is intended to have no effect on the dependent variable. The most common example of this is a sugar pill used as a placebo in a drug study.
plasticity
The brain’s ability to reorganize, or “rewire” itself, by reassigning neurons to different functions. pleasure principle
The principle by which the id is said to operate, which is to maximize pleasure and minimize pain.
pluralistic ignorance
A phenomenon in which a person does not know that there are others in the group who share his or her opinion.
polarize
To create a difference in electric potential between two surfaces. This occurs in neurons when there is a positive charge outside the axon, and a negative charge inside.
pons
A portion of the brain stem that is involved in coordinating muscular action and facial expressions. population
The group of all possible individuals from which a sample could be chosen.
positive (direct) correlation
A relationship between two variables in which the values of one variable increase as the values of the other variable increase.
positive reinforcement
Anything that causes a behavior to increase by administering something desirable in response to the behavior. post-traumatic stress disorder
A trauma- and stressor-related disorder characterized by clusters of symptoms following the experience of a traumatic event. Such clusters of symptoms include persistently reexperiencing the event, avoidance of cues related to the event, and generally increased levels of physiological arousal.
postconventional morality
The highest level of moral reasoning, characterized by commitment to moral principles.
poverty of stimulus
A hypothesis that humans must have innate language capabilities because we learn our native language in the
absence of environmental conditions, such as direct instruction or a large number of correct and incorrect examples.
preconventional morality
In Lawrence Kohlberg’s theory, the lowest stage of moral reasoning in which people make moral decisions on the basis of obtaining rewards and avoiding punishment. It is most common in children.
prefrontal cortex
The portion of the cerebral cortex that is the primary area for cognition, such as prediction, calculation, and motor planning.
preoperational
The second stage in Piaget’s theory of cognitive development, occurring from ages 2 – 7. During this stage, children are capable of using symbols in their thinking, but they lack the ability to perform logical operations.
primary mental abilities
A theory developed by Louis Leon Thurstone, who stated that individuals have six or seven primary mental abilities that make up intelligence. These primary abilities included word fluency, verbal comprehension,
numerical ability, spatial ability, general reasoning, processing speed, and associative memory.
primary motor cortex
The portion of the cerebral cortex that is the primary processing area for motor information. primary reinforcer
A reinforcer, such as a food reinforcer, that meets a basic biological need.
primary somatosensory cortex
The portion of the cerebral cortex that is the primary processing area for the sense of touch.
procedural memory
The portion of long-term memory that deals with remembering procedures, such as driving a car or playing the trombone. It is also known as implicit memory.
projective tests
A method of assessment in which the participant responds to an ambiguous stimulus, such as an inkblot. Scoring of projective measures is less reliable than scoring of objective measures.
prototype
A standard or typical example of something that serves as a model for the overall category.
proximity
A Gestalt principle of perception that states that all else being equal, things that are near one another tend to be perceived as a unit.
pruning
The process by which unused synapses are eliminated, making the brain more efficient at processing information.
pseudoscience
An activity that closely resembles science, but does not follow the principles of the scientific method.
psychiatrist
Psychiatrists attend medical school first, then specialize in the mind, and often deal with the most serious mental disorders. They can prescribe drugs and are MDs.
psychoactive drug
A substance that alters the functioning of the brain, resulting in changes of mood and behavior. psychoanalytic
A theory developed by Sigmund Freud, it focuses on intrapsychic conflict between the id, ego, and superego, as well as the influence of the unconscious mind on our lives and our behavior.
psychoanalytic model
A theory and approach developed by Sigmund Freud that focuses on intrapsychic conflicts between the id, ego, and superego, as well as the influence of the unconscious mind on our lives and our behavior.
psychodynamic perspective
A neo-Freudian theoretical perspective that focuses on unconscious mental processes and the impact of early childhood experiences on later personality and behavior.
psychologist
Psychologists may be involved in therapy, experimentation, or many other fields. They do graduate work in psychology and have master’s or doctoral degrees. Excepting some special cases, they cannot prescribe medication.
psychology
The scientific study of behavior and mental processes.
psychometric approach
An approach to personality assessment in which a large pool of items are constructed and administered to a group of people. Factor analysis is then used to determine which of the items tend to cluster together.
psychosexual
Sigmund Freud’s term for the child’s developmental stages in which sexual gratification and pleasure are
focused on a particular area of the body. Fixation at one of these psychosexual stages occurs when the tasks associated with that stage are not completed.
psychotic
Of or relating to a loss of psychological contact with reality, or an inability to distinguish the real world from the imaginary world.
punishment
Anything that follows a behavior and causes the behavior to decrease.
pupil
The opening in the center of the eye that controls how much light is let into the eye.
random assignment
In an experiment, every participant has an equal opportunity to be assigned to a particular group. Random assignment to groups is the hallmark of a “true experiment.”
random selection
A method of sampling in which every member of a population has an equal chance of being selected for the sample.
ratio schedule of reinforcement
A partial reinforcement schedule in which the organism is reinforced based upon the number of instances of the desired behavior. There can be fixed ratio schedules or variable ratio schedules.
Raven’s Matrices
A nonverbal test of intelligence that involves a series of matrix problems that get progressively more difficult. reality principle
According to Sigmund Freud, the principle on which the ego operates, which is to meet the demands of the external world.
recessive
An allele whose genetic instructions are only followed if there is no dominant allele present in the pair. reciprocal determinism
The interaction of heredity and environment in determining personality; each affects the other.
reconstructive nature of memory
The view that our memory is not a perfect recording of events that occurred; rather, we reconstruct our
memories through the filter of our present experience. Our present experience influences our recall of those events.
refractory period
The period shortly after a neuron has fired during which it is unable to fire again.
reinforcement
Anything that follows a behavior and causes the behavior to increase.
reliability
The dependability of an assessment measure, or the degree to which the measure yields consistent scores across repeated administrations (known as test-retest reliability), or across different portions of the
assessment measure (known as internal consistency).
REM
A stage of sleep characterized by rapid eye movement and nervous system arousal.
REM sleep
Most dreaming occurs during this stage, when you experience rapid eye movement.
representative
A sample that resembles the population of interest on variables that are identified as important. repression
The act of removing a memory from conscious awareness. According to some psychologists, repressed memories can be recovered in therapy, but this remains a very controversial practice.
research design
A plan for how to conduct the scientific investigation, how the variables will be manipulated and/or measured, as well as how the data will be collected and analyzed.
resting potential
The slightly negative charge (-70 millivolts) that is present in a neuron that is at rest.
reticular activating system/RAS
The part of the reticulara formation involved in regulating arousal, alertness, and sleep/wake cycles. retina
The layer of cells at the back of the eye where transduction of light waves into nerve signals takes place. It contains photoreceptors and additional neurons.
retrieval
Calling forth information from long-term memory.
retrograde amnesia
Loss of memory for events that preceded the event that caused the memory loss.
reuptake
The process by which neurotransmitters are taken back into the neuron after being released into the synapse. Reuptake stops the action of the neurotransmitter on the receptors of neighboring cells.
rods
Photoreceptors that respond to low levels of light.
Rorschach inkblot test
A projective personality test in which a respondent examines a series of inkblots and tells the examiner what he or she sees in them.
sample
A portion of a population of interest that is identified for the purposes of scientific study. If the sample is
representative and randomly selected, characteristics of the sample can be used to make inferences about the population in question.
scapegoating
The theory that prejudice can be an outlet for anger by improperly assigning blame to an individual, group, or other entity. For example, the Nazis blamed the Jews for problems in Germany.
schedule of reinforcement
A plan for how frequently a target behavior will be reinforced.
schema (development)
An internal model or mental representation that serves as a guide to perception, interpretation, or problem solving.
schema (personality)
Albert Bandura’s concept that a person’s behavior affects, and is affected by, both personal characteristics and environmental factors.
schizophrenia
A psychological disorder characterized by delusions, hallucinations, disorganized thinking or speech, disturbed perceptions, and/or inappropriate reactions or behaviors.
science
The pursuit of knowledge and understanding, using systematic methods of inquiry.
seasonal affective disorder
A depressive disorder with a seasonal pattern in which major depression occurs during the late fall and winter only.
secondary reinforcer
A reinforcer that does not in and of itself meet a basic biological need, but it can be exchanged for primary reinforcers, which would meet a basic biological need. Money is an example of a secondary reinforcer,
because it can be exchanged for food or shelter.
self-actualization
According to Abraham Maslow, self-actualization occurs when the individual’s needs have been fulfilled at all of the lower levels in the hierarchy of needs, and the individual reaches his or her full potential.
self-report
A method of assessment in which the respondent provides the information in response to interview questions or a questionnaire.
self-serving bias
A willingness to perceive oneself in the best possible light.
semantic memory
Memory for “impersonal” information, such as meanings and facts. This is in contrast with episodic memory, which is memory for events in our own lives.
semicircular canals
The three fluid-filled channels in the inner ear that are responsible for the vestibular sense, or sense of
balance. The semicircular canals respond to changes in the position of the head and the rate of movement.
sensation
The raw, unelaborated awareness of stimulation.
sensorimotor
The first stage in Jean Piaget’s cognitive developmental theory, from ages 0 to 2. During this stage, infants are learning about the environment primarily by using their senses and motor abilities.
sensory integration
A process of synthesizing information from two or more sensory systems.
sensory memory
Briefly retained information picked up by the sensory organs.
sensory neurons
Neurons that are responsible for relaying sensory information to the brain and spinal cord.
serial order (position) effects
A memory phenomenon in which the items at the beginning and end of a list are more likely to be remembered than the items in the middle of a list.
set point
The point at which an individual’s weight limit is supposedly set.
sexual orientation
The focus of a person’s sexual or romantic desires, fantasies or feelings, that describe the gender(s) to which that person is attracted.
sexual response cycle
A pattern of response to sexual stimulation, consisting of five stages: desire, excitement, plateau, orgasm, and resolution.
shaping
The process of reinforcing successive approximations of the desired behavior, until the organism is performing the desired behavior in its entirety.
short-term (working) memory
Memory that holds the information currently being used, as well as the means by which to process that information. A good analogy is that working memory is like RAM in a computer.
similarity
One of the factors that tends to be associated with attraction. We tend to be attracted to those to whom we are similar in terms of age, ethnic background, attitudes, level of physical attractiveness, and so on.
skepticism
A philosophical approach that says that nothing can be known with absolute certainty. In general, it refers to a doubting or questioning attitude.
sleep paralysis
The state of being awake but unable to speak or move. It is often a symptom of narcolepsy. social facilitation
A stronger response on a well-known task when in the presence of others.
social loafing
The tendency of people in a group to expend less effort than a person on his or her own would.
social referencing
A phenomenon in which an infant looks to significant adults for cues about how he or she should feel in a given situation.
social-cognitive
A theory developed by Albert Bandura, which states that learning occurs not only by direct experience with rewards and punishments, but also from observation of others. This theory was once called social learning theory.
soma
The body of a neuron or other cell.
somatic nervous system
The portion of the peripheral nervous system that carries messages to and from the sense organs, skin, and muscles.
somatoform disorders
Psychological disorders in which physical symptoms are present but have no apparent organic cause.
Somatoform disorders include conversion disorder and hypochondriasis disorder.
spontaneous recovery
The quick reoccurrence of a previously extinguished response when the reinforcer for the response is reintroduced.
stage 1 sleep
When one is first falling asleep; this stage lasts about 5 minutes.
stage 2 sleep
During this stage, an EEG shows bursts of activity called spindles.
stage 3 sleep
This is the beginning of deep sleep. Your breathing slows.
stage 4 sleep
Deep sleep. It is difficult to awaken while in this stage. Most sleepwalking, sleep-talking, and night terrors take place during this stage. Delta waves predominate.
standard deviation
A statistic that measures the variability, or degree of spread, of a distribution. It is calculated by taking the square root of the variance, or the average squared deviation of scores from the mean.
standardized test
A test that is carefully constructed, then administered and scored in a uniform manner.
Stanford prison experiment
An experiment by Phillip Zimbardo conducted in a mock prison that showed how quickly people adopt social roles and how strong the power of the situation is.
Stanford-Binet
An individually administered intelligence test that measures a variety of intellectual abilities.
statistical significance
A condition in which the difference between the experimental and control groups is so large that it is unlikely to have occurred by chance alone.
steroids
A class of hormones that influence a variety of processes, such as sexual functioning, body growth, and metabolism.
stimulus generalization
A phenomenon in classical conditioning in which the conditioned response occurs in response to stimuli that are similar, but not identical, to the conditioned stimulus.
strange situation task
A method developed by Mary Ainsworth and colleagues to measure the quality of infant-caregiver attachment. The strange situation task involved a baby and caregiver being brought into a playroom, where a series of
scripted events occurred, including the caregiver leaving the room, and a stranger coming into the room.
structuralism
A movement in psychology, led by Wilhelm Wundt, that focused on analyzing conscious experience in terms of its fundamental structures.
subliminal
Sensory stimulation that is below the threshold of perception, but may still influence us in some way. substance dependence
A pattern of drug use that is characterized by tolerance (needing increasing amounts of the drug to have the
same effect), withdrawal symptoms upon stopping the drug, and/or numerous unsuccessful attempts to stop or reduce substance use.
substance P
A substance that increases pain signals by stimulating nerve endings at the site of an injury.
superego
According to Freud’s theory, the portion of the personality that includes the conscience as well as the “ego ideal,” or an ideal view of one’s self.
suprachiasmic nucleus
The portion of the hypothalamus that controls the cycles of the endocrine system.
survey
A method of research in which information is systematically gathered from a representative sample of a group
on some variable of interest. The information can be gathered through interviews and/or the administration of questionnaires.
sympathetic nervous system
The portion of the autonomic nervous system that is aroused in response to stress. It is responsible for
creating the “fight or flight” response, including raising heart rate and blood pressure, as well as suppressing digestive activity.
synapse
The tiny gap between two neurons into which a neurotransmitter is released by one neuron to stimulate receptors in the dendrites of another neuron.
tastebuds
Sense organs that contain the chemical receptors for taste.
temperament
A person’s typical emotional reactivity.
temporal lobes
The lobes of the cerebral cortex that are responsible for processing information from the auditory system. teratogen
An agent that can cause damage to a developing fetus. Teratogens can be drugs, diseases, or environmental hazards.
testes
A pair of male reproductive glands that produce sperm and are contained in the scrotum in most mammals. testosterone
A male sex hormone produced by the testes.
thalamus
The portion of the brain whose primary function is to relay information from sensory systems (such as the visual system) to the cerebral cortex.
Thematic Apperception Test (TAT)
A projective personality test that involves telling stories based on cards with ambiguous drawings on them. theory
A coherent set of explanations for a phenomenon.
theory of mind
A set of explanations for how one’s own mind, and the minds of others, function.
third variable
A situation in which two variables are correlated, but neither one of them caused the other. They were both caused by another, different variable. If A and B are correlated, then C caused A and B.
threshold
The minimum sensory stimulation required for detection.
thyroid gland
An endocrine gland located in the necks of people and other vertebrate animals that secretes the hormones that control metabolism and growth.
timbre (complexity)
The quality of sound that is the result of the mixture of wavelengths in the sound.
token economy
In operant conditioning, where one can earn tokens or some other reinforcer for certain behaviors. tolerance
The capacity built up by regular use of a drug, where over time one must increase the amount of the drug taken to achieve the same level of effectiveness.
traits
Individual attributes that demonstrate some (but not perfect) consistency over time and across situations. transduction
The conversion of sensory stimuli, such as sound waves, into a form that can be processed by the sense receptors.
trauma- and stressor-related disorders
A group of disorders characterized by flashback memories, nightmares, prolonged distress, memory loss, or
avoidance that a person experiences as a result of being exposed to death, actual or threatened serious injury, or actual or threatened sexual violence. Post-traumatic stress disorder is included in this category of disorders.
triarchic theory
A theory of intelligence developed by Robert Sternberg, who states that intelligence is composed of three interrelated abilities: analytical, practical, and creative.
trichromatic (Young-Helmholtz) theory
A theory of color vision in which three types of color receptors produce the three basic colors of red, green, and blue.
trigeminal
Pertaining to fifth pair of cranial nerves, which divide on each side of the head into three main branches distributed to the orbits, jaws, and parts of the mouth.
trigeminal nerve
The largest cranial nerve, which carries both sensory and motor fibers, and affects the jaws and parts of the mouth.
two-factor theory of emotion
A theory of emotion proposed by Stanley Schacter and Jerome Singer that says that experiencing emotional states is not only a function of arousal, but also cognitive interpretations of the arousal.
unconditional positive regard
Rogers’s term for providing warmth, caring, and affection to someone, regardless of their behavior.
unconditioned response (UCR)
The unlearned, innate response to an unconditioned stimulus (UCS).
unconditioned stimulus (UCS)
A stimulus that provokes an innate, unlearned response (UCR).
unconscious
The activities of the mind that take place outside a person’s conscious awareness.
uninvolved (negligent)
One of Baumrind’s styles of parenting, in which the parent was lacking in both responsiveness and control. This parenting style was associated with the worst child adjustment of the four parenting styles.
validity
The ability of a test to measure what it is purported to measure.
variable
Anything that can take on any of a number of values.
variable schedule of reinforcement
A partial schedule of reinforcement in which the reinforcer is delivered after either varying numbers of responses (a variable ratio schedule), or varying lengths of time (a variable interval schedule).
variance
A statistic that measures the variability, or degree of spread, in the distribution. It is calculated by taking the average squared deviation of scores from the mean.
vestibular sense
The sense of balance.
visible spectrum
The part or range of wavelengths of electromagnetic radiation that is visible to the human eye.
visual cortex
The portion of the cerebral cortex responsible for processing visual information; it is located in the occipital lobes.
Weber’s law
The rule that the just noticeable difference (JND) of a stimulus is proportional to the magnitude of the original stimulus. For example, a dim light doesn’t need to brighten very much for us to notice it, but an already bright light must become much brighter for us to perceive the difference.
Weschler intelligence scales
A group of individually administered IQ tests for children and adults, which measure both verbal and nonverbal abilities.
z-score
A standardized score with a mean of 0 and a standard deviation of 1. Scores in the distributions of two
different measures, such as a measure of IQ and a measure of reading comprehension, are often converted to .z-scores so that the distributions can be easily compared with one another
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