Inclusion Criteria:  non-smokers with a score of 0-2 out of 10 maximum on the Fagerström index of smoking dependency  Exclusion Criteria:  deafness or excessive hearing loss smokers with a score between 3 and 10 on the Fagerström index of smoking dependency history of psychiatric illness, neurological disorders, diabetes mellitus, renal failure, or cardiovascular disease regular use of prescription medications (excluding oral contraceptives) drug dependency