Structuralism as a school of psychology seeks to analyze the adult mind (the total sum of experience from birth to the present) in terms of the simplest definable components and then to find how these components fit together to form more complex experiences as well as how they correlate to physical events.

William James

Rather than focusing on underlying conflicts, behaviorism focuses on observable, overt behaviors that are learned from the environment.

Sociocultural perspective

Clinical psychologists make up the single largest specialty area in psychology.

In research, the survey method allows researchers to collect large amounts of information from participants through the use of questionnaires.

Random selection refers to the method used to select your participants for the study. Random assignment is used to form groups of participants who are similar. Random selection is used to obtain a sample that is representative of the population.

WUNDT AND STRUCTURALISM Wilhelm Wundt (1832–1920) was a German scientist who was the first person to be referred to as a psychologist.

A case study is a close-up view of a group of people. One concern of standardized tests is that they may be biased to certain groups. The dependent variable is the treatment that the researcher is manipulating.

One major issue that can negatively influence experiments is by introducing cofounds into the experiment. Cofounds are things that could undermine your ability to draw causal inferences. Another major issue that can negatively influence experiments are experimenter expectations.

We can measure correlation by calculating a statistic known as a correlation coefficient. A correlation coefficient is a number from -1 to +1 that indicates the strength and direction of the relationship between variables.

The control group consists of elements that present exactly the same characteristics of the experimental group, except for the variable applied to the latter. This group of scientific control enables the experimental study of one variable at a time, and it is an essential part of the scientific method.

While all experiments have an experimental group, not all experiments require a control group. Controls are extremely useful where the experimental conditions are complex and difficult to isolate. Experiments that use control groups are called controlled experiments.

A true experiment (a.k.a. a controlled experiment) always includes at least one control group that doesn’t receive the experimental treatment. However, some experiments use a within-subjects design to test treatments without a control group.

Good experiments have two essential characteristics: a single variable is tested, and a control is used. The variable is the factor that changes in an experiment in order to test a hypothesis.

Every science experiment should follow the basic principles of proper investigation so that the results presented at the end are seen as credible.

• Observation and Hypothesis.
• Prediction and Modeling.
• Testing and Error Estimation.
• Result Gathering and Presentation.
• Conclusions.
• Law Formation.

True experiments have four elements: manipulation, control , random assignment, and random selection. The most important of these elements are manipulation and control. Manipulation means that something is purposefully changed by the researcher in the environment.

Several kinds of experimental designs exist. In general, designs that are true experiments contain three key features: independent and dependent variables, pretesting and posttesting, and experimental and control groups. In a true experiment, the effect of an intervention is tested by comparing two groups.

The experimental method involves the manipulation of variables to establish cause and effect relationships. The key features are controlled methods and the random allocation of participants into controlled and experimental groups. An experiment is an investigation in which a hypothesis is scientifically tested.

Characteristics of a Well-Designed Experiment

• Control. Control refers to steps taken to reduce the effects of extraneous variables (i.e., variables other than the independent variable and the dependent variable).
• Randomization.
• Replication.

Key Terminology

• Experimental Group. The group being treated, or otherwise manipulated for the sake of the experiment.
• Control Group.
• Ecological validity.
• Experimenter effects.
• Demand characteristics.
• Independent variable (IV)
• Dependent variable (DV)
• Extraneous variables (EV)

A good experiment needs a few things including a hypothesis (that’s testable) and a sizeable enough group of testers. It also needs a definition of success. In order to know if an experiment has failed or succeeded, you have to have a measurement for success (anything else is failure).

The three basic principles of statistical design of experiments are Control, Randomization and Repetition. When we say the design of an experiment (or experimental design), we refer to the manner in which these three principles are carried out.