Research usually begins with a prediction drawn from a theory, called a hypothesis. Common methods of gathering information systematic observation. The great strength of naturalistic observation is that investigators can see directly the everyday behaviours they hope to explain. Structured observations the investigator sets up a laboratory situation that evokes the behaviour of interest so that every participant has an equal opportunity to display the response. Structured observation permits greater control over the research situation than does naturalistic observation; the method is especially useful for studying behaviours that investigators rarely have an opportunity to see in everyday life. The great disadvantage of structured observations is that most of the time, we cannot be certain that participants behave in the laboratory as they do in their natural environments. Although systematic observation provides invaluable information on how children and adults behave, it conveys little about the reasoning that underlies their behaviour; for this kind of information, researchers must turn to self-report techniques.