murraycabulary sem 1

hindsight bias

the tendency to believe, after learning an outcome, that one would have foreseen it. (Also known as the I-knew-it-all-along phenomenon.)

hypothesis

a testable prediction, often implied by a theory.

operational definition

a carefully worded statement of the exact procedures (operations) used in a research study. For example, human 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 extends to other participants and circumstances.

case study

a descriptive technique in which one individual or group is studied in depth in the hope of revealing universal principles.

naturalistic observation

observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation.

survey

a technique for ascertaining the self-reported attitudes or behaviors of a particular group, usually by questioning a representative, random sample of the group.

sampling bias

a flawed sampling process that produces an unrepresentative sample.

population

all those in a group being studied, from which samples may be drawn.

random sample

a sample that fairly represents a population because each member has an equal chance of inclusion.

correlation

a measure of the extent to which two variables change together, and thus of how well either variable predicts the other.

correlation coefficient

a statistical index of the strength of a relationship between two variables (from -1 to +1).

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 the 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 aims to control other relevant variables.

experimental group

in an experiment, the group exposed to the treatment, that is, to one version of the independent variable.

control group

in an experiment, the group not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.

random assignment

assigning participants to experimental and control groups by chance, thus minimizing preexisting differences between the different groups.

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.

independent variable

the experimental factor that is manipulated; the variable whose effect is being studied.

confounding variable

a factor other than the independent variable that might produce an effect in an experiment.

dependent variable

the outcome factor; the variable that may change in response to manipulations of the independent variable.

validity

the extent to which a test measures or predicts what it is supposed to.

histogram

a bar graph depicting a frequency distribution.

mode

the most frequently occurring score(s) in a distribution.

mean

the arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores. Most affected by outliers.

median

the middle score in a distribution; half the scores are above it and half are below it. Best measure when there are outliers.

skewed distribution

a representation of scores that lack symmetry around their average value - outliers.

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.

normal curve (normal distribution)

a symmetrical, bell-shaped curve that describes the distribution of many types of data; most scores fall near the mean (about 68 percent fall within one standard deviation of it) and fewer and fewer near the extremes.

inferential statistics

numerical data that allow one to generalize—to infer from sample data the probability of something being true of a population.

statistical significance

a statistical statement of how likely it is that an obtained result occurred by chance.

informed consent

an ethical principle that research participants be told enough to enable them to choose whether they wish to participate.

debriefing

the postexperimental explanation of a study, including its purpose and any deceptions, to its participants.

placebo effect

experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which the recipient assumes is an active agent.

false consensus effect

the tendency to overestimate the extent to which others share our beliefs and behaviors

confirmation bias

a tendency to search for information that supports our preconceptions and to ignore or distort contradictory evidence

belief perseverance

clinging to one's initial conceptions after the basis on which they were formed has been discredited

eclectic approach

approach to psychology that combines various kinds of perspectives

Refractory period

The minimum length of time after an action potential during which another action potential cannot begin.

Action potential

A brief change in a neuron's electrical charge.

Adoption studies

Research studies that assess hereditary influence by examining the resemblance between adopted children and both their biological and their adoptive parents

Agonist

A chemical that mimics the action of a neurotransmitter.

Antagonist

A chemical that opposes the action of a neurotransmitter.

Autonomic nervous system (ANS)

The system of nerves that connect to the heart, blood vessels, smooth muscles, and glands.

Axon

A long, thin fiber that transmits signals away from the neuron cell body to other neurons, or to muscles or glands.

Central nervous system (CNS)

The brain and the spinal cord.

Cerebral cortex

The outer layer of the cerebrum - humans have largest

Corpus callosum

The structure that connects the two cerebral hemispheres.

Dendrites

Branchlike parts of a neuron that are specialized to receive information.

Electroencephalograph (EEG)

A device that monitors the electrical activity of the brain over time by means of recording electrodes attached to the surface of the scalp.

glial cells

Found throughout the nervous system that provide various types of support for neurons.

Hypothalamus

A structure found near the base of the forebrain that is involved in the regulation of basic biological needs.

Lesioning

Destroying a piece of the brain.

Mirror neurons

Neurons that are activated by performing an action or by seeing another monkey or person perform the same action. Frontal lobe

Neurotransmitters

Chemicals that transmit information from one neuron to another.

Parasympathetic NS

The branch of the autonomic nervous system that generally conserves bodily resources - calm

Peripheral nervous system

All those nerves that lie outside the brain and spinal cord.

Resting potential

The stable, negative charge of a neuron when it is inactive.

Reuptake

A process in which neurotransmitters are sponged up from the synaptic cleft by the presynaptic membrane.

Soma or cell body

Contains the nucleus and much of the chemical machinery common to most cells.

Somatic NS

The system of nerves that connect to voluntary skeletal muscles and to sensory receptors.

Split-brain surgery

A procedure in which the bundle of fibers that connects the cerebral hemispheres (the corpus callosum) is cut to reduce the severity of epileptic seizures.

Sympathetic NS

The branch of the autonomic nervous system that mobilizes the body's resources for emergencies.

Synapse

A junction where information is transmitted from one neuron to the next.

Terminal buttons

Small knobs at the end of axons that secrete chemicals called neurotransmitters.

Transcranial magnetic stimulation (TMS)

A technique that permits scientists to temporarily enhance or depress activity in a specific area of the brain.

Twin studies

A research design in which hereditary influence is assessed by comparing the resemblance of identical twins and fraternal twins with respect to a trait.

Dopamine

Excitatory - responsible for pleasure, movement, learning, attention - low levels, Parkinson's

Serotonin

Inhibitory - Mood, hunger, sleep, arousal - low levels, depression and anxiety

GABA

Balances excitatory messages - Contributes to regulation of anxiety

Glutamate

Excitatory - Thinking, memory, learning - strengthening neural connections, high levels - agitation and memory loss

Norepinephrine

Excitatory - Alertness & arousal Increasing heartbeat, arousal, memory, learning, and eating

Acetylcholine

Excitatory - Muscle action/contractions; learning/memory - Messenger at every junction between motor neuron & skeletal muscle - low levels, paralysis, Alzheimers

Endorphins

Inhibitory - "morphine within" - natural opiates, pain control and pleasure

Frontal Lobe

planning, judgment, memory, reasoning, abstract thinking, movement (motor cortex) *mirror neurons

Parietal Lobe

Important area governing spatial awareness and navigation - information about touch (sensory cortex), Left hemisphere involved in mathematics, reading, writing and understanding symbols.

Temporal Lobe

hearing (auditory cortex), Wernicke's for language

Occipital Lobe

visual information (visual cortex)

Broca's Aphasia

Damage that makes speech very slow, slurred and labored, no comprehension problems

Wernicke's Aphasia

Damage where speech is incomprehensible - patients have great difficulty understanding - Speech is NOT slurred

Lateralization/contralateral control

hemispheres control the opposite sides of the body

hippocampus

creates, integrates, consolidates memories

Amygdala

Damage to this region leads to decrease in fear, aggression, and sexual desire

hypothalamus

Helps to govern endocrine system and controls maintenance functions - eating and drinking

Cerebellum

enables nonverbal learning, coordinates voluntary movements

Reticular formation

regulates sleep, wakefulness, and levels of arousal - damage would lead to coma

Medulla

Controls heartbeat and breathing

CAT Scan

Provides structural imaging using Xrays

fMRI

Provides functional imaging of active brain areas using magnetic fields

Plasticity

the ability of the brain to form and reorganize synaptic connections, compensate for damage

Substance P

A neurotransmitter that is involved in the transmission of pain messages to the brain.

sensation

the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.

perception

the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.

bottom-up processing

analysis that begins with the sensory receptors and works up to the brain's integration of sensory information.

top-down processing

information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations.

selective attention

the focusing of conscious awareness on a particular stimulus.

inattentional blindness

failing to see visible objects when our attention is directed elsewhere.

change blindness

failing to notice changes in the environment.