psychology
the science of behavior and mental processes
nature-nurture issue
the long-standing controversy over the relative contributions that genes and experience make to the development of psychological traits and behaviors
natural selection
the principle that, among the range of inherited trait variations, those contributing to reproduction and survival will most likely be passed on to succeeding generations
neuroscience
the perspective of psychological science that deals with how the body and brain create emotions, memories, and sensory experiences
evolutionary
the perspective of psychological science that deals with how nature selects traits that promote the perpetuation of one's genes
behavior genetics
the perspective of psychological science that deals with how much our genes, and our environment, influence our individual differences
psychodynamic
the perspective of psychological science that deals with how behavior springs from unconscious drives and conflicts
behavioral
the perspective of psychological science that deals with how we learn observable responses
cognitive
the perspective of psychological science that deals with how we encode, process, store, and retrieve information
social-cultural
the perspective of psychological science that deals with how behavior and thinking vary across situations and cultures
basic research
pure science that aims to increase the scientific knowledge base
applied research
scientific study that aims to solve practical problems
clinical psychology
a branch of psychology that studies, assesses, and treats people with psychological disorders
psychiatry
a branch of medicine dealing with psychological disorders, practiced by physicians who sometimes provide medical (for example, drug) treatments as well as psychological therapy
hindsight bias (I-knew-it-all-along phenomenon)
the tendency to believe, after learning an outcome, that one would have foreseen it
critical thinking
thinking that does not blindly accept arguments and conclusions. Rather, it examines assumptions, discerns hidden values, evaluates evidence, and assesses conclusions
theory
an explanation using an integrated set of principles that organizes and predicts observations
hypothesis
a testable prediction, often implied by a theory
operational definition
a statement of the procedures (operations) used to define research variables. For example, intelligence may be operationally defined as what an intelligence test measures
replication
repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding generalizes to other participants and circumstances
case study
an observation technique in which one person is studied in depth in the hope of revealing universal principles
survey
a technique for ascertaining the self-reported attitudes or behaviors of people, usually by questioning a representative, random sample of them
false consensus effect
the tendency to overestimate the extent to which others share our beliefs and behaviors
population
all the cases in a group, from which samples may be drawn for a study
random sample
a sample that fairly represents a population because each member has an equal chance of inclusion
naturalistic observation
observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation
correlation coefficient
a statistical measure of the extent to which two factors vary together, and thus of how well either factor predicts the other
scatterplot
a graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of correlation (little scatter indicates high correlation).
illusory correlation
the perception of a relationship where none exists
experiment
a research method in which an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (the dependent variable). By random assignment of participants the experimenter controls other relevant factors)
placebo
an inert substance or condition that may be administered instead of a presumed active agent, such as a drug, to see if it triggers the effects believed to characterize the active agent
double-blind procedure
an experimental procedure in which both the research participants and the research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo. Commonly used in drug-evaluation studies.
placebo effect
any effect on behavior caused by a placebo
experimental condition
the condition of an experiment that exposes participants to the treatment, that is, to one version of the independent variable
control condition
the condition of an experiment that contrasts with the experimental condition and serves as a comparison for evaluation the effect of the treatment
random assignment
assigning participants to experimental and control conditions by chance, thus minimizing preexisting differences between those assigned to the different groups
independent variable
the experimental factor that is manipulated; the variable whose effect if being studied
dependent variable
the experimental factor--in psychology, the behavior or mental process--that is being measured; the variable that may change in response to the manipulations of the independent variable
mode
the most frequently occurring score in a distribution
mean
the arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores
median
the middle score in a distribution; the scores are above it and half are below it
range
the difference between the highest and lowest scores in a distribution
standard deviation
a computed measure of how much scores vary around the mean score
statistical significance
a statistical criterion for rejecting the assumption of no differences in a particular study
culture
the enduring behaviors, ideas, attitudes, and traditions shared by a large group of people and transmitted from one generation to the next
Biological psychology
concerned with links between biology and behavior
Neuron
building blocks of the nervous system
Dendrite
Branches designed to receive/send/and transport information
Axon
transports messages to different muscles/glands in the body
Action potential
a neural impulse; a brief electrical charge that travels down an axon. The action potential is generated by the movement of positively charged atoms in and out of channels in the axon's membrane.
Myelin sheath
a layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next
Threshold
the level of stimulation required to trigger a neural impulse
Synapse
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or cleft
Neurotransmitters
chemical messengers that traverse the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether it will generate a neural impulse
Acetylcholine
a neurotransmitter that, among its functions, triggers muscle contraction
Endorphins
"morphine within" - natural, opiatelike neurotransmitters linked to pain control and to pleasure.
Nervous system
the body's speedy, electrochemical communication system, consisting of all the nerve cells of the peripheral and central nervous systems.
Central nervous system (CNS)
the brain and spinal cord
Peripheral nervous system (PNS)
The sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body
Nerves
Neural "cables" containing many axons. These bundled axons, which are part of the peripheral nervous system, connect the central nervous system with muscles, glands, and sense organs
Sensory neurons
neurons that carry incoming information from the sense receptors to the central nervous system
Interneurons
central nervous system neurons that intervene between the sensory inputs and motor outputs
Motor neurons
The neurons that carry outgoing information from the central nervous system to the muscles and glands
Somatic nervous system
the division of the peripheral nervous sytem that controls the body's skeletal muscles.
Autonomic nervous system
the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.
Sympathetic nervous system
The division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations
Parasympathetic nervous system
The division of the autonomic nervous system that calms the body, conserving its energy
Reflex
a simple, automatic, inborn response to a sensory stimulus, such as the knee-jerk response
Neural networks
interconnected neural cells. With experience, networks can learn, as feedback strengthens or inhibits connections that produce certain results. Computer stimulations of neural networks show analogous learning.
Phrenology
an ill-fated theory that claimed bumps on the skull could reveal our mental abilities and our character traits.
lesion
tissue destruction. A brain lesion is a naturally or experimentally caused destruction of brain tissue
EEG (electroencephalogram)
an amplified recording of the waves of electrical activity that sweep across the brain's surface. These waves are measured by electrodes placed on the scalp
CT (computed tomography)
a series of x-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body
PET (positron emission tomography)
a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task
MRI (magnetic resonance imaging)
a technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue; allows us to see structures within the brain
brainstem
the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions
medulla
the base of the brainstem; controls heartbeat and breathing
reticular formation
a nerve network in the brainstem that plays an important role in controlling arousal
thalamus
the brain's sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla
cerebellum
the "little brain" attached to the rear of the brainstem; it helps coordinate voluntary movement and balance
limbic system
a doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheres; associated with emotions such as fear and aggression and drives such as those for food and sex. Includes the hippocampus, amygdala, and hypothalamus
amygdala
two almond-shaped neural clusters that are components of the limbic system and are linked to emotion
hypothalamus
a neural structure lying below the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion
cerebral cortex
the intricate fabric of interconnected neural cells that covers the cerebral hemispheres; the body's ultimate control and information-processing center
glial cells
cells in the nervous system that are not neurons but that support, nourish, and protect neurons
frontal lobes
the portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgement
parietal lobes
the portion of the cerebral cortex lying at the top of the head and toward the rear; includes the sensory cortex
occipital lobes
the portion of the cerebral cortex lying at the back of the head; includes the visual areas, which receive visual information from the opposite visual field
temporal lobes
the portion of the cerebral cortex lying roughly above the ears, includes the auditory areas, each of which receives auditory information primarily from the opposite ear
motor cortex
an area at the rear of the frontal lobes that controls voluntary movements
sensory cortex
the area at the front of the parietal lobes that registers and processes body sensations
association areas
areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking
aphasia
impairment of language, usually caused by left hemisphere damage to either Broca's area (impairing speaking) or to Wernicke's area (impairing understanding)
Broca's Area
an area of the frontal lobe, usually in the left hemisphere, that directs the muscle movements involved in speech
Wernicke's area
a brain area involved in language comprehension and expression; usually in the left temporal lobe
plasticity
the brain's capacity for modification, as evident in the brain reorganization following damage (especially in children) and in experiments on the effects of experience on brain development
corpus callosum
the large band of neural fibers connecting the two brain hemispheres and carrying messages between them
split brain
a condition in which the two hemispheres of the brain at isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them
endocrine system
the body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream
hormones
chemical messengers, mostly those manufactured by the endocrine glands, that are produced in one tissue and affect another