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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.)

Theory

An explanation using an intergrated set of principles that organizes observations and predicts behaviors or events.

Hypothesis

A testable predisction, often implied by a theory.

Oprational Definition

A carefully worded statement of the exact proedures (operations) used in a research study. For example, human intelligence may be operationally defined as what an intelligence test measures.

Replication

Repeating the esence of a research study, usually with different participants in different situations, to see whether the basic finding can be reproduced.

Case Study

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

Naturalistic Observation

A descriptive technique of observing and recording behavior in naturally occuring situations without trying to manipulate and control the situation

Survey

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

Random Sample

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

Population

All those in a group being studies, from which samples may be drawn(Note: Except for national studies, this does not refer to a country's whole population.)

Correlation

A measure of the extent to which two factors vary together, and thus of how well either factor predicts the other.

Correlation Coefficient

A statistical index of the relationship between two things (From -1.00 + 1.00)

Variable

Anything that can vary and is feasible and ethical to measure

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 stength of the correlation (little scatter high correlation)

Illusory Correlation

Percieving a relationship where none exists, or percieving a stronger than actual relationship

Regression toward the mean

The tendency for extreme or unusual scores or events to fall back (regress) toward the average

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 factors.

Experimetal 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 affect of the treatment

Random Assignment

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

Double-click procedure

An experimental procedure in which both the research participants and the research staff are ignorant (blind) about whether the research participants have recieved the treatment or a placebo. Commonly used in drug-evaluation studies.

Placebo effect

Experiments 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

Independent Variable

In an experiment, the factor that is manipulated

the variable whose effect is being studied

Confounding Variable

A factor other than the factor being studied that might influence a study's results

Dependent Variable

In an experiment, the outcome that is measured

the variable that may change when the indepedent variable is manipulated

Informed Consent

Giving potential participants enough information about a study 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

Mode

The most frequenty occuring scores 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

half 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 such scores vary around the mean score

Normal Curve (normal distribution)

A symmetrical, bell shaped curve that describes the distibution 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

Statistical Signifiance

A statistical statement of how likely it is that an obtained result occured by chance

Biological psychology

The scientific study of the links between biological (genetic, neural, hormonal) and psychological processes. Some biological psychological call themselves behavioral neuroscientists, nueropsychologists, or biopsychologists

Plasticity

The brains ability to change, escpecially during childhood, by reorganizing after damage or by building new pathways based on experience

Neuron

A nerve cell

the basic building block of the nervous system

Cell body

The part of a neuron that contains the nuclues

the cells life support center

Dendrites

A neurons often bushy, branching extensions that recieve and intergrate messages, conducting impulses toward the cell body

Axon

The neuron extensions that passes messages through its branches to other neurons or to muscles or glands

Myelin Sheath

A fatty tissue layer segmentally encasing the axons of some neurons

enables vastly greater transmission speed as neural impulses hop from one node to the next

Glial cells

Cells in the nervous system that support,nourish, and protect neurons

they also play a role in learning, thinking and memory

Action Potential

A neural impulse

a brief electrical charge that travels down an axon

Threshold

The level of stimulation required to trigger a neural impulses

Refactory Period

In neural processing, a brief resting pause that occurs after a neuron has fired

subsequent action potentials cannot occur until the axon returns to its resting state

All-or-none response

A neurons reaction of either firing (with a full-strength response) or not firing

Synapse

The junction between the axon tip of the sending neuron and the dendrite or cell body of the recieving neuron. The tiny gap at this junction is called the synaptic gap or synaptic cleft

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the recieving neuron, thereby influencing whether that neuron will generate a neural impulse

Reuptake

A neurotransmitters reabsorption by the sending neuron

Endorphins

"morphine within" natural, opiate-like neurotransmitters linked to pain control and to pleasure

Agonist

A molecule that increases a neurotransmitters action

Antagonist

A molecule that inhibits or blocks a neurotransmitters action

Nervous System

The bodys speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems

Central nervous system (CNS)

the brain and spinal cord

Peripheral Nervous System (PNS)

the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body

Nerves

Bundled axons that forms neural cables connecting the central nervous system with muscles, glands, and sense organs

Sensory (afferent) neurons

Neurons that carry incoming information from the bodys tissues and sensory receptors to the brain and spinal cord

Motor (efferent) neurons

Neurons that carry outgoing information ffrom the brain and spinal cord to the muscles and glands

Somatic Nervous System

The division of the peripheral nervous system that controls the bodys 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 parasympthetic division calms

Sympathetic Nervous System

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

endocrine system

the bodys "slow" chemical communication system

a set of glands that secrete hormones into the bloodstream

Hormones

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

Electroencephalogram (EEG)

An amplified recording of the waves of electrical activity sweeping across the brains surface. These waves are measured by electrodes placed on the scalp.

Magnetoencephalography (MEG)

A brain imaging technique that measures magnetic fields from the brains natural electrical activity

PET (positron emission tomography) scan

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 computergenerated images of soft tissue. MRI scans show brain anatomy

fMRI (functional MRI)

a technique for revealing bloodflow and, therefore, brain activity by comparing successive MRI scans. fMRI scans show brain functions as well as structure

Brainstem

The oldest part and central core of the brain, beginning where the spiinal 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.

Thalamus

The brains sensory control center, located on top of the brainstem

it directs messages to the sensory recieving areas in the cortex and transmits replies to the cerebellum and medulla

Reticular Formation

A nerve network that travels through the brainstem into the thalamus and plays an important role in conntrolling arousal

Cerebellum

The "little brain" at the rear of the brainstem

functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory

Limbic System

Neural system (including the amgdal,hypothalamus, and hippocamppus) located below the cerebal hemisheres

associated with emotions and drives

Amygdala

Two limabean sized neural clusters in the limbic system

linked to emotion

Hypothalamus

A neural structure lying below (hypo) 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 and reward

Hippocampus

A neural center located in the limbic system

helps process explicit (conscious) memories-of facts and events-for storage

Cerebral Cortex

The intricate fabric of interconnected neural cells covering the cerebral hemispheres