A Level Psychology OCR Practice Exam

The study conducted by Sperry et al. in 1968 utilized an opportunity sample, which means they selected participants who were readily available and accessible at the time of the study. This type of sampling method is often used in psychological research due to practicality and convenience, especially when researchers have limited resources or time constraints.

Sperry's study focused on individuals who had undergone a specific surgical procedure, known as commissurotomy, which involved severing the corpus callosum to alleviate epilepsy. Therefore, the participants were a unique group of people who were already available to the researchers because of their medical circumstances. This focused approach reflects an opportunity sample, as it capitalized on an existing pool of subjects without attempting to achieve a random selection of the general population.

Using an opportunity sample can allow for more immediate access to participants but may also introduce biases based on the particular context or characteristics of the available subjects, which Sperry’s study needed to account for, considering the specific medical condition of the participants.