As technological advances lead to more understanding of the brain, or the “hardware” of human thought, the importance of understanding the “software” that is, cognitive functions, has become even more important. There has been progress in the cognitive sciences in understanding the basic processes of cognition and how these processes relate to the operations and behaviors of the organism in the environment. Among the most intensely studied processes are those relating to attention and working memory (e.g., inhibition, updating, and coordination) and higher level cognitive abilities such as planning, reasoning, comprehension, and problem solving, which are attributed to circuits associated with the brain's frontal lobe. One reason for this accelerating interest is the rapid progress in those areas of cognitive psychology and cognitive neuroscience that focus on working memory and neuroimaging research (Andrade, 2001; Cabeza & Nyberg, 2000; Davidson, Pizzagalli, Nitschke, & Putnam, 2002; Gazzaniga, Ivry, & Mangum, 1998; Logie & Gilhooly, 1999; Miyake & Shah, 1999; Richardson et al., 1996). Another reason for this surge of interest is that many populations, such as older adults (Craik & Salthouse, 2000; Perfect & Maylor, 2000; Rabbitt, 1997), persons with emotional disorders (Hertel, 1997; von Hecker & Sedek, 1999; Williams, Watts, MacLeod, & Mathews, 1997), and individuals with brain injuries (Waltz et al., 1999), have demonstrated cognitive limitations with respect to attention, working memory, and other so-called executive functions.