Effects of peppermint and cinnamon odor administration on simulated driving alertness, mood and workload.

Past research indicates that the presence of peppermint and cinnamon odors during human performance assessment can dramatically influence motivation, task performance, and alertness. In a series of studies, Warm and colleagues investigated the efficacy of certain odors to enhance performance accuracy on a tedious vigilance or sustained attention task. The bulk of these studies (Dember, Warm & Parasuraman, 1996; Jones, Ruhl, Warm & Dember, 1999; Warm, Dember & Parasuraman, 1991) indicate that participants were able to detect more critical signals during the vigil when presented with either muguet or peppermint, than they were with unscented air. More recently, Raudenbush and colleagues (Raudenbush, Corley, & Eppich, 2001; Raudenbush, Meyer, & Eppich, 2002) examined the effects of odorants on athletic performance. In a series of studies, they administered various odors (e.g., peppermint, jasmine, dimethyl sulfide) to athletes performing a modified treadmill stress test. Peppermint odor significantly reduced perceived physical workload, temporal workload, effort, and frustration, as assessed by the Profile of Mood States (POMS; McNair, Lorr & Droppleman, 1971) and the NASA-Task Load Index (NASA-TLX; Hart & Staveland, 1988). Self-evaluated performance was also greater in the peppermint condition, and participants rated their level of vigor higher and their level of fatigue lower. In addition, when assessing performance on specific athletic tasks, those athletes exposed to peppermint odor were found to complete a quarter mile run more quickly, perform more push-ups, and exhibit increased hand dynamometer grip strength. Zoladz and Raudenbush (2005) have examined the effects of odorant administration on augmenting cognitive performance. Their study was divided into two phases: Phase I investigated the effects of retronasal (ie., through the mouth) odorants, while Phase II investigated the effects of orthonasal (ie., through the nose) odorants. During Phase I, participants completed computerized neuro-cognitive tasks under five chewing gum conditions (no gum, flavorless gum, peppermint gum, cinnamon gum, and cherry gum). Assessments included a wide range of cognitive abilities, such as word discrimination, attention, verbal recognition memory, visual recognition memory, visual processing speed, retention memory for novel symbols, reaction time, impulse control/response inhibition, working memory, and visual-motor response speed. During Phase II, participants completed the assessments under four odorant conditions (no odor, peppermint odor, jasmine odor, and cinnamon odor), delivered via low flow (1.3 L/min) oxygen through a nasal cannula. Both cinnamon and peppermint odor, administered either retronasally or orthonasally, improved participants' scores on tasks related to attentional processes, virtual recognition memory, working memory, and visualmotor response speed. In addition, participants rated their mood and level of vigor higher, and their level of fatigue lower, in the peppermint condition. Previous studies also indicate that odors have widespread effects on the human central nervous system (Kobal & Hummel, 1988; Lorig & Schwartz, 1988; Van Toller, 1988). These researchers noted substantial changes in EEG activity during the administration of various odors, particularly peppermint. One explanation for the changes noted in EEG activity relates to attentional differences; EEG pattens change predictably when individuals actively attend to stimulus presentations. However, further research suggests that differences occurred even if the individuals were unaware that an odor was being administered (Lorig, Huffman & DeMartino, 1991). Given the above results, it is reasonable to expect that the presentation of certain odors while driving may produce a more alert and conscientious driver, and minimize the fatigue associated with prolonged driving. Research by Baron and Kalsher (1998) had participants complete a compensatory tracking task where they were to use a joystick to keep a moving stimulus within two vertical lines. …