CASE STUDIES

A case study is an observational method that provides a description of an individual. This individual is usually a person, but it may also be a setting such as a business, school, or neighborhood. A naturalistic observation study is sometimes called a case study, and in fact the naturalistic observation and case study approaches sometimes overlap. We have included case studies as a separate category in this chapter because case studies do not necessarily involve naturalistic observation. Instead, the case study may be a description of a patient by a clinical psychologist or a historical account of an event such as a model school that failed. A psychobiography is a type of case study in which a researcher applies psychological theory to explain the life of an individual, usually an important historical figure (Schultz, 2005). Thus, case studies may use such techniques as library research and telephone interviews with persons familiar with the case but no direct observation at all (Yin, 2014).

Depending on the purpose of the investigation, the case study may present the individual’s history, symptoms, characteristic behaviors, reactions to situations, or responses to treatment. Typically, a case study is done when an individual possesses a particularly rare, unusual, or noteworthy condition. One famous case study involved a man with an amazing ability to recall information (Luria, 1968). The man, called “S.,” could remember long lists and passages Page 126with ease, apparently using mental imagery for his memory abilities. Luria also described some of the drawbacks of S.’s ability. For example, he frequently had difficulty concentrating because mental images would spontaneously appear and interfere with his thinking.

Another case study example concerns language development; it was provided by “Genie,” a child who was kept isolated in her room, tied to a chair, and never spoken to until she was discovered at the age of 13½ (Curtiss, 1977). Genie, of course, lacked any language skills. Her case provided psychologists and linguists with the opportunity to attempt to teach her language skills and discover which skills could be learned. Apparently, Genie was able to acquire some rudimentary language skills, such as forming childlike sentences, but she never developed full language abilities.

Individuals with particular types of brain damage can allow researchers to test hypotheses (Stone, Cosmides, Tooby, Kroll, & Knight, 2002). The individual in their study, R.M., had extensive limbic system damage. The researchers were interested in studying the ability to detect cheaters in social exchange relationships. Social exchange is at the core of our relationships: One person provides goods or services for another person in exchange for some other resource. Stone et al. were seeking evidence that social exchange can evolve in a species only when there is a biological mechanism for detecting cheaters; that is, those who do not reciprocate by fulfilling their end of the bargain. R.M. completed two types of reasoning problems. One type involved detecting violations of social exchange rules (e.g., you must fulfill a requirement if you receive a particular benefit); the other type focused on nonsocial precautionary action rules (e.g., you must take this precaution if you engage in a particular hazardous behavior). Individuals with no brain injury do equally well on both types of measures. However, R.M. performed very poorly on the social exchange problems but did well on the precautionary problems, as well as other general measures of cognitive ability. This finding supports the hypothesis that our ability to engage in social exchange relationships is grounded in the development of a biological mechanism that differs from general cognitive abilities.

Case studies are valuable in informing us of conditions that are rare or unusual and thus providing unique data about some psychological phenomenon, such as memory, language, or social exchange. Insights gained through a case study may also lead to the development of hypotheses that can be tested using other methods.