Psychology Keywords

The science of human development is the science that seeks to understand how and why people change or remain the same over time. Developmentalists study people of all ages and circumstances.

Based on observation, experience, or experiment; not theoretical.

A view of human development as always changing. Life is the product of ongoing interaction between the physical and emotional being and between the person and every aspect of his or her environment, including the family and society.

Flux is constant, and each change affects the others.

ecological-systems approach

A vision of how human development should be studied, with the person considered in all the contexts and interactions that constitute a life.

butterfly effect

The idea that a small effect or thing can have a large impact if it happens to tip the balance, causing other changes that create a major event.

cohort

A group of people who were born at about the same time and thus move through life together, experiencing the same historical events and cultural shifts.

Socio-economic status (SES)

A person's position in society as determined by income, wealth, occupation, education, place of residence, and other factors.

Ethic group

People whose ancestors were born in the same region and who often share a language, culture, and religion.

Race

A group of people who are regarded by themselves or by others as genetically distinct from other groups on the basis of physical appearance.

Social construction

An idea that is built more on shared perceptions than on objective reality. Many age-related terms, such as childhood, adolescence, yuppies, and senior citizens are social constructions.

Mirror neurons

Brain cells that respond to actions performed by someone else, as if the observer had done that action. For example, the brains of dancers who witness another dancer moving onstage are activated in the same movement areas as would be activated if they themselves did that dance step, because their mirror neurons reflect the activity.

scientific method

A way to answer questions that requires empirical research and data-based conclusions.

hypothesis

A specific prediction that is stated in such a way that it can be tested and either confirmed or refuted.

Replication

• The repetition of a scientific study, using the same procedures on a similar but not identical
• group of participants, in order to verify, refine, or dispute the original study's conclusions.

• A method of testing hypotheses by unobtrusively watching and recording particpant's behavior in a
• systematic and objective manner, either in a laboratory or in a natural setting.

A research method in which the researcher tries to determine the cause-and-effect relationship between two variables by manipulating one variable [called the independent variable] and then observing and recording the resulting changes in the other variable [called the dependent variable].

independent variable

In an experiment, the variable that is introduced to see what effect it has on the dependent variable. Also called the experimental variable.

Dependent variable

• In an experiment, the variable that may change as a result of whatever new condition or situation
• the experimenter adds. In other words, the dependent variable depends on the independent variable.

Experimental group

A group of participants in a research study who experience some special treatment or condition [the independent variable].

Comparison group / control group

A group of participants in a research study who are similar to the experimental group in all relevant ways but who do not experience the experimental condition [the independent variable].

Survey

A research method in which information is collected from a large number of people by interviews, written questionaires, or some other means.

Case-study

A research method in which one individual is studied intensively.

cross-sectional research

A research design that compares groups of people who differ in age but who are similar in other important characteristics.

longitudinal research

A research design in which the same individuals are followed over time and their development is repeatedly assessed.

cross-sequential research

• A hybrid research method in which researchers first study several groups of people of different
• ages [a cross-sectional approach] and then follow those groups over the years [a longitudinal
• approach]. [Also called cohort-sequential research or time-sequential research.]

correlation

• A number indicating the degree of relationship between the two variables expressed in terms of the
• likelihood that one variable will [or will not] occur when the other variable does or does not. A
• correlation is not an indication that one variable causes the other, only that the two variables
• are related to the indicated degree.

quantitative research

Research that provides data that can be expressed with numbers, such as ranks or scales.

qualitative research

• Research that considers qualities instead of quantities. Descriptions of particular conditions and
• participants' expressed ideas are often part of qualitative studies.

code of ethics

A set of moral principles that members of a profession or group are expected to follow.