There are a number of methods researchers use to study human behavior. The method chosen depends on many factors including cost, facilities, the researchers goals and preferences, the behavior to be studied and the purpose or goals of the study.

Some of the experimental methods are easier for the researcher to control and therefore produce more conclusive results than others. However, all experiments begin with an experimental hypothesis, typically derived from existing theory, - in other words what the experimenter expects to happen. This article will briefly describe what the methods are and the pros and cons for each.

A. The Controlled Experiment

The experimenter directly manipulates the presence or strength of a factor or variable and measures how behavior is affected by it. That is, the experimenter controls all factors and manipulates one (referred to as the Independent variable) and observes/measures the effects of this variable on some measure of behavior (the resulting behavioral measurement is referred to as the Dependent variable)

An Example:

Hypothesis: Stress has a detrimental effect on performance.

Independent Variable (designed to manipulate the level of stress)

(e.g. subjects given different feedback on their performance in an academic test

Levels:

1.) Subjects informed they performed poorly (experimental group)

2.) Subjects told nothing (control group)

Dependent Variable (the measurement of for example reaction time and error rate on a separate task - performed after the feedback/no feedback)

The performance of the experimental group (high stress condition) is then compared to that of the control group (no stress condition). If the performance of the experimental group is statistically poorer (slower reaction times and more errors) compared to the control group, then the experimental hypothesis is said to be supported.

Pros: the experimenter directly controls the variables to be studied and this type of experiment is typically performed in a laboratory where conditions can be controlled.

Cons: experimenter bias can play a part in the results in that the subjects can 'pick up on' what the experimenter wants to happen and perform according to expectations. Also, it can be difficult to generalize results obtained in the lab to behavior in the real world.

B. The Observational Method

This involves simply observing and describing behavior in specific settings. These observations can lead to 'tighter' hypotheses, which can be tested more rigorously using the experimental method (see above)

Pros: can give the investigator greater insight into a behavior and lead to more accurate hypotheses

Cons: it can be difficult using this method to separate cause and effect.

C. The Correlational Method

This method is used when psychologists want to study relationships between variables, which they cannot control or experimentally manipulate due to either practical or ethical reasons (e.g. the effect of natural disasters on future coping strategies, or if a person is abused as a child what is the likelihood that they will abuse their own children?)

Both A and C are designed to study relationships between variables but in C no attempt is made to manipulate the variables. Instead, naturally occurring variations in both the independent and dependent variable are simply measured to see how they relate to each other.

This relationship is measured via a statistical test referred to as a correlation coefficient (r). If r is +1.00 there is a perfect positive relationship, if it is -1.00 there is a perfect negative relationship and if r is 0 there is no relationship between the 2 variables being measured.

Pros: can study behavior in natural environments and can help to structure future predictions.

Cons: it is difficult if not impossible to say with any real certainty if the variables are related - thus cause and effect is difficult to determine.

D. Case Studies

The study of individuals, which include detailed biographical reconstruction, information derived from observation, interview with the person, their spouse and/or other acquaintances that know the person to be studied etc. Most often used by clinical and personality psychologists. Can also be used with specific groups (e.g. patients with Obsessive Compulsive Disorder).

Pros: can lead to complete theory changes or can direct further, more controlled experimental studies.

Cons: typically there is a lack of a control population, the observations are based on individuals and therefore tend to be difficult to generalize to the wider population.

E. Surveys and Tests

These can be used to study important topics (e.g. attitudes to racism) that are difficult to study via direct observation.

Pros: can test a large number of people via questionnaires and interviews. Is cost-effective.

Cons: predictions are only as good as the questions on the survey/test, people can be biased to respond in order to make themselves appear more 'favorable' - therefore can be open to lying and/or misinterpretation of the questions by the respondents.

Conclusions

The experimental method is the most popular and the strongest method used by psychologists in their attempts to study behavior. It is the only research method that shows a cause and effect relationship. The other methods can be useful however in that they can direct testing of specific hypotheses and ultimately test existing theories.