Krieger Psychology

Positively Skewed Distribution

Contains a preponderance of scores on the low end of the scale. The mean will be higher than the median in a positively skewed distribution.

Negatively Skewed Distribution

Contains a preponderance of scores on the low end of the scale. The mean will be lower than the median in a negatively skewed distribution.

Humanistic Perspective

Emerged from the pioneering work of Carl Rogers and Abraham Maslow. Emhasizes that importance of self-esteem, free will, and choice in human behavior.

Behavioral Perspective

Emerged from the pioneering work of Carl Rogers and John B. Watson, and B.F Skinner. Emphasizes observable behavior that can be objectively measured.

Neurotransmitters

Chemical transmitters manufactered by a neuron. For example, acetycholine is associated with Alzheimer's disease, dopamine is linked to schizophrenia, and serotoin is related to depression.

Psychoanalytic/ Psychodynamic Perspective

Emerged from the pioneering work of Sigmund Freud. Emphasizes that role of unconscious conflicts in determining behavior and personality.

Biological Perspective

Emphasizes genetics, the roles of carious parts of the brain, and the structutre and function of individual nerve cells.

Independent Variable

Factor in an experiment that researchers manipulate so that they can determine its effect.

Control Group

Group that is exposed to all experimental conditions, except the independent variable.

Experimental Group

Group that is exposed to the independent variable.

Cognitive Perspective

Influenced by the computer revolution, the cognitive perspective compares the mind to a computer that encodes, processes, and stores information. Cognitive Psychologist emphasize thinking, perceiving, and information processing.

Evolutionary Perspective

Influenced by the seminal writings of Charles Darwin. Emphasizes the role played by natural selection and adaptation in the evolution of behavior and mental processes.

Hypothalamus

Small brain structure beneath the thalamus that helps govern the release of hormones by the pituitary gland and regulates drives such as hunger and thirst.

Depndent Variable

the outcome; the factor that changes due to the other variable

Endorphins

Chemical substances in the nervous system that reduce the perception of pain.

Normal Distribution

A bell-shaped curve, describing the spread of a characteristic throughout a population. In a normal distribution, half the scores fall at or above the mean and half the scores fall at or below the mean.

Action Potential

A brief electrical impulse by which information is transmitted along the axon of a neuron.

Experimental Method

A carefully controlled scientific procedure involving the manipulation of variables to determine cause and effect. The experimental method enables researchers to determine cause and effect relationships.

Neuron

A highly specialized nerve cell responsible for receiving and transmitting information in electrical and chemical forms. Neurosn are the fundamental building blocks of the nervous system

Median

A measure of central tendency that divides a frequency distribution exactly in half.

Mode

A measure of central tendency that identifies the most frequently occuring score in a distribution.

Mean

A measure of central tendency that provides the average score. Any change in the higest score in a distribution must result in a change in mean.

Standard Deviation

A measure of variability that indicates the average differences between the scores and their mean.

Correlation Coefficient

A numerical value from +1.00 to -1.00 that indicates the strength and direction of the relationship between two variables. A positive correlation indicates that the two variables move or vary in the same direction. A negative correlation indicates that the two variables move or vary in opposite directions. A zero correlation indicates that there is no relationship between the two variables.

Double-blind Study

A procedure in which neither the researcher nor the participant knows which group received the experimental treatment. Designed to reduce experimenter bias.

Cerebral Cortex

A thin surface layer on the cerebral hemispheres that regulates most complex behavior, including sensations, motor control, and higher mental processes such as decision making.

Myelin Sheath

A white, fatty covering wrapped around the axos of some neurons, which increases the rate at which nerve impulses travel along the axon.

Case Study

An in-depth examination of a single research participant.

Parasympathetic Nervous System

Branch of the automatic nervous system that calms the body, maintains bodily functions, and conserves energy.

Sympathetic Nervous System

Branch of the automatic nervous system that produces rapid physical arousal in response to perceived emergencies or threats.

Cerebral Hemispheres

The nearly symmetrical left and right halves of the cerebral cortex. The left hemisphere specializes in verbal and analytical functions. The right hemisphere focuses on nonverbal abilities such as art and music and visual recognition tasks.

All-Or-Nothing Law

The principle that either a neuron is sufficiently stimulated and an action potential occers or a neuron is not sufficiently stimulated and an action potential does not occur.

P-Value

The probability of concluding that a difference exists when in fact the difference does not exist. A statistically significant difference is a difference is a difference not likely due to chance. By consensus, a statistically significant difference is one that would show up only 5 percent of the time or less. The smaller the p-value the more significant the results.

Correlation Research

The researcher observes or measures two or more naturally occuring variables to find the relationship between them. In correlation research, the researcher does not directly manipulate the variables.

Confounding Variable

Variables that have an unwanted influence on the outcome of an experiment. Also known as extraneous variables.