Lastly, individuals may respond differently to caffeine and carbonation, thus affecting EEG recordings to some degree To control for the varying effects of caffeine, a non-caffeinated beverage could be included; however, it has been found that
caffeine typically increases alertness levels (Hartley, Lovallo, & Whitsett, 2004; Lane & Williams, 2007) and amplifies EEGs (Liu et al., 2004; Guger et al., 2009) indiscriminately across the brain. Finally, tests should include more than one stimulus
and include products that participants currently use in order to gauge their willingness to switch