Task analysis complements neuroimaging: an example from working memory research

When functional neuroimaging researchers draw conclusions about the sensory, cognitive, or motor processes that are associated with changes in brain activity, they are making assumptions about the component processes involved in performing a complex behavioral task. We demonstrate the danger in making such assumptions using, as an example, the n-back task, which has been widely used in neuroimaging studies of working memory. Neuroimaging researchers have assumed that the letter n-back task only engages processes involved in the short-term maintenance and manipulation of verbal information. We report three behavioral experiments demonstrating that the letter n-back task additionally recruits spatial processes. A fourth experiment suggested that the location n-back task may recruit verbal processes in addition to spatial processes. These results call into question conclusions that have been drawn about the neural basis of working memory. More broadly, our results demonstrate that task analysis is a vital partner of neuroimaging in the cognitive neuroscience enterprise.